clear_a from_o the_o bensil_n of_o the_o air_n g_o f_o which_o in_o effect_n counterpoise_v the_o weight_n of_o the_o whole_a atmosphere_n rest_v upon_o the_o surface_n of_o water_n a_o b._n we_o see_v second_o that_o when_o the_o pondus_fw-la and_o the_o potentia_fw-la of_o two_o fluid_n be_v in_o equilibrio_n or_o of_o equal_a strength_n a_o very_a small_a addition_n to_o either_o of_o they_o will_v cast_v the_o balance_n for_o if_o a_o man_n shall_v but_o breathe_v soft_o upon_o the_o side_n of_o the_o glass_n between_o g_z and_o f_o or_o lay_v his_o warm_a hand_n to_o it_o the_o say_a air_n will_v present_o dilate_v itself_o and_o by_o become_v thus_o strong_a thrust_v down_o the_o water_n and_o so_o overcome_v the_o potentia_fw-la of_o the_o surface_n we_o see_v three_o a_o confirmation_n of_o the_o six_o theorem_n namely_o that_o the_o pressure_n of_o fluids_n be_v on_o every_o side_n as_o be_v clear_a from_o the_o enclose_a air_n g_o f_o that_o not_o only_o press_v down_o the_o water_n f_o d_o but_z with_o as_o great_a force_n press_v up_o the_o top_n of_o the_o glass_n within_o and_o press_v upon_o all_o the_o side_n of_o it_o within_o with_o the_o same_o force_n this_o experiment_n also_o lead_v we_o to_o the_o knowledge_n of_o two_o thing_n first_o of_o the_o reason_n why_o with_o cold_a the_o water_n ascend_v in_o the_o common_a weather-glass_n and_o why_o in_o hot_a weather_n the_o water_n descend_v second_o from_o this_o experiment_n we_o may_v learn_v to_o know_v when_o the_o air_n be_v under_o a_o great_a pressure_n and_o when_o under_o a_o lesser_a because_o when_o the_o air_n become_v heavy_a as_o in_o fair_a weather_n the_o water_n creep_v up_o in_o some_o measure_n it_o may_v be_v two_o or_o three_o inch_n when_o there_o be_v no_o alteration_n as_o to_o heat_n and_o cold_a and_o in_o foul_a weather_n or_o in_o great_a wind_n when_o the_o air_n be_v real_o light_a the_o say_a water_n creep_v down_o as_o much_o if_o it_o be_v ask_v how_o shall_v i_o know_v whether_o it_o be_v the_o cold_a of_o the_o air_n or_o heaviness_n of_o the_o air_n that_o cause_v the_o water_n to_o ascend_v and_o whether_o it_o be_v the_o heat_n of_o the_o air_n or_o the_o lightness_n of_o the_o air_n that_o cause_v the_o water_n to_o descend_v i_o have_v propose_v this_o question_n of_o purpose_n to_o let_v you_o see_v a_o mistake_n many_o believe_v that_o the_o ascent_n and_o descent_n of_o water_n in_o common_a weather-glass_n be_v allanerly_a from_o the_o heat_n and_o coldness_n of_o the_o air_n and_o therefore_o they_o conclude_v a_o cold_a day_n to_o be_v because_o the_o water_n be_v far_o up_o whereas_o the_o water_n have_v ascend_v since_o the_o last_o night_n by_o reason_n of_o a_o great_a weight_n in_o the_o air_n which_o always_o be_v when_o the_o weather_n be_v dry_a and_o calm_a though_o there_o have_v be_v no_o alteration_n of_o heat_n to_o cold_a if_o it_o be_v ask_v how_o come_v we_o to_o the_o knowledge_n of_o this_o that_o the_o pressure_n and_o weight_n of_o the_o element_n of_o air_n be_v sometime_o less_o and_o sometime_o more_o i_o answer_v this_o secret_a o_o nature_n be_v never_o discover_v till_o the_o invention_n of_o the_o torricellian_a experiment_n otherwise_o call_v the_o baroscope_n for_o after_o the_o fall_v down_o of_o the_o quicksilver_n to_o 29_o inch_n if_o you_o suffer_v it_o to_o stand_v thus_o in_o your_o parlour_n or_o chamber_n according_a as_o the_o pressure_n and_o weight_n of_o the_o element_n of_o air_n become_v more_o or_o less_o so_o will_v the_o altitude_n of_o the_o mercury_n become_v less_o or_o more_o and_o vary_v sometime_o above_o 29_o inch_n and_o sometime_o below_o this_o alteration_n be_v very_o sensible_a which_o be_v sometime_o the_o ten_o part_n of_o a_o inch_n sometime_o the_o six_o and_o sometime_o the_o three_o according_a as_o the_o weight_n of_o the_o air_n be_v less_o or_o more_o from_o december_n to_o february_n i_o find_v the_o alteration_n become_v less_o and_o more_o from_o 30_o inch_n to_o 28_o which_o will_v be_v three_o finger_n breadth_n the_o common_a weather-glass_n than_o be_v fallacious_a and_o deceitful_a unless_o they_o be_v so_o contrive_v that_o the_o pressure_n of_o the_o air_n can_v affect_v they_o which_o be_v easy_o do_v by_o seal_v they_o hermetical_o and_o in_o stead_n of_o common_a water_n to_o put_v in_o spiritus_fw-la vini_n rectificatissimus_fw-la or_o the_o most_o excellent_a spirit_n of_o wine_n and_o strong_a that_o can_v be_v make_v it_o may_v be_v here_o inquire_v whether_o or_o not_o mercury_n will_v ascend_v in_o this_o glass_n as_o the_o water_n do_v i_o answer_v it_o will_v because_o the_o ascent_n depend_v only_o upon_o the_o pressure_n of_o the_o air_n incumb_a upon_o the_o stagnant_a liquor_n in_o the_o vessel_n that_o be_v able_a to_o drive_v up_o mercury_n as_o well_o as_o water_n it_o may_v be_v inquire_v second_o how_o far_o mercury_n will_v ascend_v and_o how_o far_o water_n will_v creep_v up_o i_o answer_v mercury_n can_v ascend_v no_o high_o in_o a_o tub_n than_o 29_o inch_n and_o water_n no_o high_o than_o 34_o foot_n and_o this_o only_o happen_v when_o there_o be_v no_o air_n above_o the_o top_n of_o the_o cylinder_n to_o hinder_v their_o ascent_n but_o when_o there_o be_v air_n as_o g_o f_o above_o the_o liquor_n it_o can_v go_v no_o high_o than_o the_o point_n to_o which_o the_o cold_a be_v able_a to_o contract_v the_o enclose_a air_n which_o be_v in_o this_o glass_n the_o point_n f._n it_o may_v be_v inquire_v three_o which_o be_v the_o great_a difficulty_n whether_o or_o not_o mercury_n will_v rise_v as_o easy_o in_o a_o tub_n as_o water_n for_o see_v it_o be_v 14_o time_n heavy_a it_o seem_v the_o air_n shall_v have_v great_a difficulty_n to_o press_v it_o up_o than_o to_o press_v up_o water_n i_o answer_v it_o be_v great_a difficulty_n for_o the_o air_n to_o press_v up_o 20_o inch_n of_o mercury_n than_o to_o press_v up_o 20_o inch_n of_o water_n yet_o it_o be_v no_o great_a difficulty_n for_o the_o air_n to_o press_v up_o 20_o inch_n of_o mercury_n than_o to_o press_v up_o 23_o foot_n of_o water_n because_o the_o burden_n and_o weight_n be_v the_o same_o it_o may_v be_v inquire_v four_a whether_o or_o not_o it_o be_v as_o easy_a for_o the_o air_n to_o press_v up_o a_o thick_a and_o gross_a cylinder_n of_o water_n as_o to_o press_v up_o a_o thin_a and_o slender_a one_o for_o example_n whether_o be_v it_o as_o easy_a for_o the_o air_n to_o press_v up_o a_o cylinder_n of_o water_n 10_o inch_n in_o diameter_n and_o 10_o foot_n high_a as_o it_o be_v to_o press_v up_o one_o two_o inch_n in_o diameter_n and_o 10_o foot_n high_a i_o answer_v there_o be_v no_o more_o difficulty_n in_o the_o one_o than_o in_o the_o other_o and_o the_o reason_n be_v because_o fluid_a body_n do_v not_o counterpoise_v one_o another_o according_a to_o their_o thickness_n but_o only_o according_a to_o their_o altitude_n according_a to_o the_o four_o theorem_fw-la therefore_o see_v the_o slender_a cylinder_n be_v as_o high_a as_o the_o grosser_n it_o must_v be_v no_o more_o difficult_a to_o the_o air_n to_o press_v up_o the_o one_o than_o the_o other_o there_o be_v one_o difficulty_n yet_o remain_v which_o be_v true_o the_o great_a of_o all_o namely_o what_o be_v the_o reason_n why_o its_o more_o difficult_a to_o the_o air_n to_o press_v up_o 20_o inch_n of_o mercury_n than_o to_o press_v up_o 20_o inch_n of_o water_n or_o more_o difficult_a to_o the_o air_n to_o press_v up_o 20_o inch_n of_o mercury_n than_o to_o press_v up_o 10_o i_o answer_v this_o come_v to_o pass_v because_o the_o air_n be_v more_o burden_a with_o 20_o inch_n of_o mercury_n than_o with_o 10._o now_o if_o this_o be_v then_o sure_o it_o must_v be_v more_o hard_a to_o the_o air_n to_o do_v the_o one_o than_o to_o do_v the_o other_o even_o as_o it_o be_v more_o hard_a for_o a_o man_n to_o lift_v up_o from_o the_o ground_n 20_o pound_n of_o iron_n than_o to_o lift_v up_o 10_o or_o 15._o the_o case_n may_v be_v better_o illustrate_v after_o this_o manner_n suppose_v a_o man_n stand_v on_o the_o ground_n with_o a_o rope_n in_o his_o hand_n come_v down_o from_o a_o pulley_n above_o draw_v up_o a_o weight_n to_o the_o top_n of_o the_o house_n put_v the_o case_n likewise_o the_o weight_n be_v a_o stone_n of_o 20_o pound_n and_o the_o weight_n of_o it_o to_o increase_v successive_o as_o it_o be_v pull_v up_o now_o its_o easy_a for_o the_o man_n to_o pull_v up_o the_o stone_n the_o first_o fathom_n because_o it_o be_v but_o 20_o pound_n weight_n but_o the_o stone_n become_v 40_o pound_n in_o the_o second_o fathom_n and_o 60_o in_o the_o three_o and_o
a_o open_a trade_n w._n c._n hydrostatical_a theorem_n contain_v some_o useful_a principle_n in_o order_n to_o that_o excellent_a doctrine_n anent_o the_o wonderful_a weight_n force_n and_o pressure_n of_o the_o water_n in_o its_o own_o element_n theorem_fw-la i._n in_o all_o fluid_n beside_o the_o first_o and_o visible_a horizontal_n surface_n there_o be_v many_o more_o imaginary_a yet_o real_a figure_n 1._o for_o the_o better_a understanding_n the_o follow_a experiment_n it_o be_v needful_a to_o premit_fw-la the_o subsequent_a theorem_n the_o first_o whereof_o be_v that_o in_o all_o fluid_a body_n such_o as_o air_n water_n and_o mercury_n or_o any_o other_o liquid_a there_o be_v beside_o the_o first_o and_o visible_a surface_n innumerable_a more_o imaginary_a under_o that_o first_o yet_o real_a as_o may_v be_v see_v from_o the_o follow_a schematism_n which_o represent_v a_o vessel_n full_a of_o water_n where_o beside_o the_o first_o surface_n a_o b_o c_o d_o the_fw-mi be_v a_o second_v e_o f_o g_o h_n and_o a_o three_o i_o k_o l_o m_o and_o so_o downward_o till_o you_o come_v to_o the_o bottom_n this_o hold_v true_a not_o only_o in_o water_n but_o in_o air_n also_o or_o in_o any_o other_o fluid_a body_n whatsoever_o i_o call_v the_o under-surfaces_a imaginary_a not_o because_o they_o be_v not_o real_a for_o true_a and_o real_a effect_n be_v perform_v by_o they_o but_o because_o they_o be_v not_o actual_o distinguish_v among_o themselves_o but_o only_o by_o the_o intellect_n theorem_fw-la ii_o in_o all_o fluid_n as_o it_o be_v needful_a to_o conceive_v horizontal_n plain_n so_o it_o be_v needful_a to_o conceive_v perpendicular_a pillar_n cut_v these_o plain_n at_o right_a angle_n figure_n 1._o this_o proposition_n be_v likewise_o needful_a for_o understand_v the_o follow_a doctrine_n anent_o the_o pressure_n of_o the_o water_n for_o in_o it_o as_o in_o all_o fluid_n though_o there_o be_v not_o colume_n or_o pillar_n actual_o divide_v reach_v from_o the_o top_n to_o the_o bottom_n yet_o there_o be_v innumerable_a imaginary_a which_o do_v as_o real_o produce_v effect_n by_o their_o pressure_n as_o if_o they_o be_v actual_o distinguish_v these_o imaginary_a pillar_n be_v represent_v in_o the_o first_o schematism_n one_o whereof_o be_v a_o e_o i_o n_o o_o p_o q_o the_o other_o b_o f_o k_o r_o t_o and_o so_o forth_o theorem_fw-la iii_o there_o be_v a_o twofold_a balance_n one_o natural_a another_o artificial_a by_o the_o artificial_a balance_n i_o understand_v that_o which_o the_o mechanic_n call_v libra_n which_o merchant_n common_o use_v by_o the_o natural_a balance_n which_o for_o distinction_n cause_v i_o so_o nominat_fw-la i_o mean_v v_o g._n a_o siphoâ—_n or_o crooked_a pipe_n wherein_o water_n natural_o ascend_v or_o descend_v as_o high_a or_o low_o in_o the_o one_o leg_n as_o in_o the_o other_o still_o keep_v a_o evenness_n or_o likeness_n of_o weight_n theorem_fw-la iu._n fluid_fw-la body_n counterpoise_v one_o another_o in_o the_o balance_n of_o nature_n according_a to_o their_o altitude_n only_o this_o theorem_fw-la will_v appear_v afterward_o most_o evident_a while_o we_o pass_v through_o the_o several_a experiment_n and_o it_o be_v of_o special_a use_n for_o explicate_v sundry_a difficulty_n that_o common_o occur_v in_o the_o hydrostaticks_n the_o meaning_n of_o it_o be_v short_o this_o while_o two_o cylinder_n of_o water_n be_v in_o the_o opposite_a scale_n of_o the_o natural_a balance_n they_o do_v not_o counterpoise_v one_o another_o according_a to_o their_o thickness_n for_o though_o the_o one_o pillar_n of_o water_n be_v ten_o time_n thick_a than_o the_o other_o and_o consequent_o heavy_a yet_o be_v it_o not_o able_a to_o press_v up_o the_o other_o that_o be_v more_o slender_a and_o so_o light_a beyond_o its_o own_o height_n and_o therefore_o they_o weigh_v only_o according_a to_o their_o altitude_n theorem_fw-la v._n in_o all_o fluid_n there_o be_v a_o pressure_n figure_n 1._o this_o be_v true_a not_o only_o of_o the_o element_n of_o air_n and_o water_n while_o they_o be_v out_o of_o their_o own_o place_n as_o they_o speak_v but_o while_o they_o be_v in_o it_o for_o air_n and_o water_n be_v natural_o endue_v with_o weight_n the_o second_o foot_n can_v be_v under_o the_o first_o unless_o it_o sustain_v it_o if_o this_o be_v it_o must_v necessary_o be_v press_v with_o its_o burden_n so_o this_o water_n be_v natural_o a_o heavy_a body_n the_o foot_n i_o can_v be_v under_o e_o unless_o it_o sustain_v it_o and_o be_v press_v with_o the_o burden_n of_o it_o the_o foot_n n_o be_v burden_v with_o they_o both_o from_o this_o pressure_n which_o be_v in_o air_n arise_v a_o certain_a sort_n of_o force_n and_o power_n which_o may_v be_v call_v bensil_n by_o virtue_n whereof_o a_o little_a quantity_n of_o air_n can_v expand_v and_o spread_v out_o itself_o to_o a_o very_a large_a quantity_n and_o may_v be_v extrinsic_a force_n be_v reduce_v to_o that_o small_a quantity_n again_o though_o this_o expansive_a faculty_n be_v evident_a in_o air_n yet_o it_o be_v scarce_o discernible_a in_o water_n unless_o it_o be_v in_o very_o deep_a part_n near_o the_o bottom_n where_o the_o pressure_n be_v great_a this_o pressure_n be_v not_o of_o the_o same_o degree_n in_o all_o the_o part_n but_o be_v increase_v and_o augment_v according_a to_o the_o deepness_n of_o the_o air_n and_o water_n for_o the_o air_n upon_o the_o top_n of_o mountain_n and_o high_a place_n be_v think_v to_o be_v of_o a_o less_o pressure_n then_o in_o valley_n and_o water_n be_v of_o a_o less_o pressure_n ten_o or_o twelve_o foot_n from_o the_o top_n than_o twenty_o or_o thirty_o so_o be_v the_o water_n n_o under_o a_o far_o less_o pressure_n than_o the_o water_n p_o or_o q._n theorem_fw-la vi._n the_o pressure_n of_o fluids_n be_v on_o every_o side_n figure_n 1._o the_o meaning_n be_v that_o air_n and_o water_n press_v not_o only_o downward_o but_o upward_o not_o to_o the_o right_a hand_n only_o but_o to_o the_o leave_v also_o and_o every_o way_n so_o the_o foot_n of_o water_n k_o not_o only_o press_v down_o the_o foot_n r_o but_o press_v up_o the_o foot_n f_o yea_o press_v the_o foot_n i_o and_o the_o foot_n l_o with_o the_o same_o weight_n and_o the_o first_o imaginary_a surface_n be_v as_o much_o press_v up_o by_o the_o water_n i_o k_n l_o m_o as_o it_o be_v press_v down_o by_o the_o water_n e_o f_o g_o h._n upon_o this_o account_n it_o be_v that_o when_o a_o sphere_n or_o glob_v be_v suspend_v in_o the_o middle_n of_o water_n or_o air_n all_o the_o point_n of_o their_o surface_n be_v uniform_o press_v after_o this_o manner_n be_v our_o body_n press_v with_o the_o environ_v air_n and_o the_o man_n that_o dive_v with_o the_o ambient_fw-la and_o environ_v water_n theorem_fw-la vii_o all_o the_o part_n of_o a_o fluid_a in_o the_o same_o horizontal_n line_n be_v equal_o press_v figure_n 1._o the_o meaning_n be_v that_o the_o foot_n i_o be_v no_o more_o press_v than_o the_o foot_n k_o neither_o be_v the_o foot_n l_o more_o burden_v than_o the_o foot_n m._n the_o reason_n be_v because_o each_o of_o these_o foot_n sustain_v the_o same_o weight_n for_o e_z f_o g_o h_n be_v all_o of_o they_o of_o the_o same_o burden_n therefore_o all_o the_o part_n of_o a_o fluid_a in_o the_o same_o horizontal_n surface_n be_v press_v most_o equal_o this_o hold_v true_a in_o air_n and_o mercury_n or_o in_o any_o othâ—â—_n liquid_a also_o theorem_fw-la viii_o the_o pressure_n of_o fluids_n seem_v to_o be_v according_a to_o arithmetical_a progression_n figure_n 1._o the_o meaning_n be_v that_o if_o the_o first_o foot_n of_o water_n have_v one_o degree_n of_o pressure_n in_o it_o the_o second_o must_v have_v only_o two_o and_o the_o three_o must_v have_v only_o three_o and_o so_o forth_o which_o appear_v from_o the_o schematism_n for_o the_o first_o foot_n e_o have_v one_o degree_n of_o weight_n and_o the_o second_o foot_n i_o have_v of_o its_o self_n as_o much_o and_o sustain_v e_z it_o must_v have_v two_o degree_n and_o no_o more_o so_o the_o foot_n n_o sustain_v two_o degree_n of_o pressure_n from_o i_o and_o e_o must_v have_v the_o weight_n only_o of_o three_o degree_n o_o of_o four_o p_o of_o five_o it_o be_v evident_a also_o from_o experience_n for_o while_n by_o the_o pressure_n of_o water_n mercury_n be_v suspend_v in_o a_o glass_n tub_n we_o find_v that_o as_o the_o first_o fourteen_o inch_n of_o water_n sustain_v one_o inch_n of_o mercury_n so_o the_o second_o fourteen_o inch_n sustain_v but_o two_o and_o the_o three_o but_o three_o but_o if_o the_o pressure_n be_v according_a to_o geometrical_a progression_n the_o three_o foot_n of_o water_n ought_v to_o sustain_v four_o inch_n of_o mercury_n the_o four_o eight_o the_o five_o sixteen_o etc._n etc._n which_o be_v contrary_a to_o experience_n
theorem_fw-la ix_o in_o all_o fluid_n there_o be_v a_o twofold_a weight_n one_o sensible_a the_o other_o insensible_a the_o first_o be_v common_a to_o all_o heavy_a body_n which_o we_o find_v in_o water_n while_o we_o lift_v a_o vessel_n full_a of_o it_o from_o the_o ground_n the_o insensible_a weight_n of_o water_n and_o air_n or_o of_o any_o other_o fluid_a can_v scarce_o be_v discern_v by_o the_o sense_n though_o it_o be_v as_o real_a as_o the_o former_a because_o the_o pressure_n be_v uniform_a by_o virtue_n of_o the_o second_o bodies_z natural_o light_a than_o water_n be_v drive_v from_o the_o bottom_n to_o the_o top_n as_o cork_n so_o a_o man_n fall_v into_o a_o deep_a water_n go_v present_o to_o the_o bottom_n and_o instant_o come_v up_o again_o here_o be_v a_o natural_a effect_n which_o can_v want_v a_o natural_a cause_n and_o this_o can_v be_v nothing_o else_o but_o the_o pressure_n of_o the_o water_n by_o virtue_n whereof_o he_o come_v up_o and_o yet_o he_o find_v nothing_o drive_v he_o up_o or_o pull_v he_o up_o therefore_o there_o be_v in_o all_o fluid_a body_n a_o insensible_a weight_n as_o there_o be_v one_o sensible_a see_v the_o man_n that_o perhaps_o weigh_v seventeen_o stone_n be_v drive_v up_o fifteen_o or_o sixteen_o fathom_n by_o it_o and_o it_o must_v be_v very_o considerable_a and_o exceed_v the_o weight_n of_o the_o man_n see_v it_o be_v able_a to_o overcome_v such_o a_o weight_n so_o be_v vapour_n and_o smoke_n drive_v upward_o by_o the_o insensible_a weight_n of_o the_o air_n and_o by_o that_o same_o weight_n do_v the_o cloud_n swim_v above_o we_o theorem_fw-la x._o the_o insensible_a weight_n of_o fluids_n be_v only_o find_v by_o sense_n when_o the_o pressure_n be_v not_o uniform_a for_o understanding_n of_o this_o proposition_n i_o must_v suppose_v something_n that_o be_v possible_a but_o not_o practicable_a put_v the_o case_n then_o while_o a_o man_n open_v his_o hand_n the_o air_n below_o be_v remove_v he_o will_v scarce_o be_v able_a to_o sustain_v the_o weight_n of_o the_o air_n that_o rest_v upon_o the_o palm_n above_o or_o if_o the_o air_n above_o be_v annihilate_v he_o will_v not_o be_v able_a to_o bear_v down_o the_o weight_n that_o press_v upward_o or_o while_o a_o diver_n be_v in_o the_o bottom_n of_o the_o sea_n if_o it_o be_v possible_a to_o free_v any_o one_o part_n of_o his_o body_n from_o the_o pressure_n of_o the_o water_n suppose_v his_o right_a arm_n i_o doubt_v not_o but_o the_o blood_n will_v spring_v out_o in_o abundance_n from_o his_o finger-end_n for_o the_o arm_n be_v free_a and_o the_o other_o part_n extreme_o press_v the_o blood_n of_o necessity_n must_v be_v drive_v from_o the_o shoulder_n downward_o with_o force_n which_o can_v be_v without_o considerable_a pain_n it_o be_v evident_a also_o from_o the_o application_n of_o the_o cuppin-glass_n which_o be_v due_o apply_v to_o a_o man_n skin_n cause_v the_o air_n to_o press_v unequal_o the_o part_n without_o be_v more_o press_v than_o the_o part_n within_o in_o which_o case_n the_o unequal_a pressure_n cause_v the_o pain_n and_o so_o be_v find_v by_o sense_n theorem_fw-la xi_o a_o cylinder_n of_o water_n or_o of_o any_o other_o fluid_a body_n lose_v of_o its_o weight_n according_a to_o its_o reclination_n from_o a_o perpendicular_a position_n towards_o a_o horizontal_n or_o level_v situation_n for_o understanding_n of_o this_o consider_v that_o while_n a_o pipe_n full_a of_o water_n stand_v perpendicular_a the_o low_a foot_n sustain_v the_o whole_a weight_n of_o the_o water_n above_o it_o but_o no_o soon_o you_o begin_v to_o recline_v the_o pipe_n from_o that_o position_n but_o assoon_o the_o pressure_n upon_o the_o low_a foot_n grow_v less_o so_o that_o if_o the_o low_a foot_n in_o a_o perpendicular_a position_n sustain_v the_o burden_n of_o ten_o foot_n it_o can_v sustain_v above_o five_o or_o six_o when_o it_o be_v half_o recline_v a_o certain_a evidence_n whereof_o be_v this_o the_o more_o a_o cyilnder_n of_o water_n be_v recline_v towards_o the_o horizon_n or_o level_v it_o take_v the_o short_a cylinder_n of_o water_n to_o counterpoise_v it_o as_o be_v evident_a in_o siphons_n for_o though_o the_o one_o leg_n be_v sixteen_o inch_n long_o and_o the_o other_o but_o six_o yet_o a_o cylinder_n of_o water_n six_o inch_n long_o will_v counterpoise_v a_o cylinder_n of_o sixteen_o but_o this_o can_v be_v unless_o a_o alteration_n be_v make_v in_o the_o pressure_n for_o how_o be_v it_o possible_a that_o a_o cylinder_n of_o water_n can_v sometime_o be_v in_o aequilibrio_fw-la with_o a_o lesser_a and_o sometime_o with_o a_o great_a weight_n unless_o the_o weight_n and_o pressure_n of_o it_o be_v sometime_o more_o and_o sometime_o less_o when_o i_o say_v a_o cylinder_n of_o water_n lose_v of_o its_o weight_n by_o reclination_n it_o be_v to_o be_v understand_v only_o of_o the_o insensible_a weight_n for_o the_o sensible_a weight_n be_v unchangeable_a see_v it_o be_v always_o a_o pillar_n of_o so_o many_o inch_n or_o foot_n now_o the_o true_a reason_n why_o the_o pressure_n upon_o the_o low_a foot_n grow_v less_o be_v this_o the_o more_o the_o pipe_n be_v recline_v the_o more_o weight_n of_o the_o cylinder_n rest_n upon_o the_o side_n of_o the_o pipe_n within_o by_o which_o mean_n the_o low_a foot_n be_v ease_v of_o the_o burden_n and_o be_v altogether_o ease_v when_o once_o the_o pipe_n lie_v horizontal_n theorem_fw-la xii_o all_o motion_n in_o fluids_n be_v from_o the_o unequal_a pressure_n of_o the_o horizontal_n surface_n figure_n 1._o for_o understand_v this_o i_o must_v distinguish_v a_o twofold_a motion_n in_o fluids_n one_o common_a another_o proper_a by_o virtue_n of_o the_o first_o they_o incline_v as_o all_o other_o heavy_a body_n to_o be_v at_o the_o centre_n of_o the_o earth_n it_o be_v evident_a in_o the_o motion_n of_o river_n which_o descend_v from_o the_o high_a place_n to_o the_o valley_n even_o by_o virtue_n of_o that_o tendency_n they_o have_v to_o be_v at_o the_o centre_n by_o virtue_n of_o the_o second_o they_o incline_v to_o move_v every_o way_n not_o only_o downward_o but_o upward_o hither_o and_o thither_o this_o sort_n of_o motion_n be_v peculiar_a and_o proper_a only_a to_o fluids_n and_o it_o be_v that_o which_o be_v speak_v of_o in_o this_o theorem_fw-la i_o say_v then_o that_o all_o motion_n in_o fluids_n be_v from_o the_o unequal_a pressure_n of_o the_o horizontal_n surface_n for_o put_v the_o case_n a_o be_v more_o press_v then_o b_o e._n g._n with_o a_o stone_n then_o sure_o as_o the_o part_n a_o descend_v the_o other_o part_n b_o will_v ascend_v and_o so_o will_n c_o and_o d_o rise_v high_o too_o suppose_v next_o the_o part_n a_o be_v fir_v of_o the_o pressure_n of_o the_o air_n then_o sure_o in_o the_o same_o instant_n of_o time_n will_v the_o part_v a_o ascend_v and_o the_o part_n b_o c_o d_o descend_n as_o this_o proposition_n be_v true_a in_o order_n to_o the_o first_o and_o visible_a surface_n a_o b_o c_o d_o so_fw-mi it_o be_v true_a in_o order_n to_o the_o imaginary_a surface_n i_o k_o l_o m_o for_o put_v the_o case_n the_o space_n i_o be_v fill_v with_o a_o body_n natural_o heavy_a than_o water_n as_o lead_v or_o stone_n than_o behove_v that_o part_n of_o the_o surface_n to_o yield_v it_o be_v more_o press_v than_o the_o part_n of_o the_o same_o surface_n k._n or_o if_o the_o space_n k_n be_v fill_v with_o a_o body_n natural_o light_a than_o water_n as_o cork_n then_o ought_v the_o water_n r_o to_o ascend_v it_o be_v less_o press_v than_o the_o water_n n_o or_o s._n theorem_fw-la xiii_o a_o body_n natural_o heavy_a than_o water_n descend_v and_o a_o body_n natural_o light_a ascend_v figure_n 1._o for_o understanding_n of_o this_o let_v we_o suppose_v the_o quadrat_fw-la space_n e_z to_o be_v fill_v with_o a_o piece_n of_o lead_n or_o iron_n i_o say_v then_o it_o must_v go_v down_o to_o i_o and_o the_o reason_n be_v because_o the_o quadrat_fw-la foot_n of_o water_n i_o be_v more_o press_v than_o the_o quadrat_fw-la foot_n of_o water_n k._n to_o illustrat_fw-la this_o let_v we_o suppose_v that_o each_o quadrat_fw-la foot_n of_o this_o water_n weigh_v a_o pound_n and_o that_o the_o heavy_a body_n exist_v in_o e_o weigh_v two_o pound_n if_o this_o be_v the_o foot_n of_o water_n i_o must_v yield_v see_v it_o be_v more_o press_v than_o k_o upon_o the_o same_o account_n must_v the_o water_n n_o yield_v and_o give_v way_n to_o the_o stone_n see_v it_o be_v more_o press_v then_o r._n for_o according_a to_o the_o twelve_o theorem_n there_o can_v be_v unequal_a pressure_n upon_o a_o surface_n unless_o motion_n follow_v for_o understand_v the_o second_o part_n let_v we_o suppose_v the_o space_n r_o to_o be_v fill_v with_o a_o piece_n of_o cork_n
for_o example_n if_o instead_o of_o the_o stone_n there_o be_v place_v a_o bladder_n full_a of_o wind_n within_o the_o water_n and_o tie_v to_o the_o bottom_n with_o a_o string_n that_o the_o surface_n may_v swell_v from_o h_n i_o to_o a_o b_o the_o water_n of_o the_o vessel_n will_v become_v as_o much_o heavy_a than_o before_o as_o be_v the_o bulk_n of_o water_n equal_a to_o the_o quantity_n of_o the_o bladder_n therefore_o the_o water_n become_v heavy_a not_o because_o it_o support_v any_o part_n of_o the_o stone_n but_o because_o the_o stone_n occupy_v as_o much_o room_n and_o space_n as_o will_v contain_v 10_o pound_n of_o water_n for_o by_o this_o mean_v the_o drown_a stone_n raise_v the_o water_n from_o h_n i_o to_o a_o b_o and_o so_o the_o cylinder_v a_o c_o and_o b_o d_o be_v high_a press_v with_o great_a weight_n upon_o the_o bottom_n c_o d_o even_o with_o as_o much_o more_o weight_n as_o if_o the_o space_n that_o the_o stone_n occupy_v be_v fill_v with_o water_n for_o answer_v to_o this_o we_o shall_v make_v this_o follow_a experiment_n take_v the_o vessel_n m_o p_o v_o x_o and_o fill_v it_o with_o water_n to_o q_o r._n next_o take_v a_o large_a bladder_n w_n y_fw-fr full_a of_o wind_n and_o tie_v the_o neck_n with_o a_o thread_n thrust_v it_o below_o the_o water_n and_o fasten_v it_o to_o the_o bottom_n with_o a_o string_n to_o the_o ring_n z._n this_o do_v the_o water_n swell_v and_o rise_v from_o q_o r_o to_z m_o p._n now_o if_o it_o be_v true_a that_o the_o water_n in_o the_o vessel_n become_v heavy_a not_o because_o it_o support_v 10_o pound_n weight_n of_o the_o stone_n but_o because_o the_o stone_n occupy_v the_o room_n of_o 10_o pound_n of_o water_n than_o it_o ought_v to_o follow_v that_o after_o the_o bladder_n be_v tie_v below_o the_o water_n the_o say_a water_n shall_v become_v heavy_a than_o before_o even_o by_o three_o pound_n for_o i_o suppose_v a_o bulk_n of_o water_n equal_a to_o the_o bulk_n of_o the_o bladder_n to_o weigh_v as_o much_o and_o the_o reason_n be_v because_o as_o you_o say_v the_o quantity_n of_o the_o bladder_n w_n y_fw-fr make_v the_o water_n swell_v from_o q_o r_o to_o m_o p_o by_o which_o mean_v the_o pillar_n of_o water_n m_o v_n and_o p_o x_o become_v high_a and_o so_o press_v with_o great_a weight_n upon_o the_o bottom_n five_o x._o for_o clear_v this_o difficulty_n i_o say_v when_o a_o bladder_n be_v thus_o below_o the_o water_n tie_v to_o the_o bottom_n the_o water_n become_v not_o three_o pound_n heavy_a for_o when_o you_o place_v the_o vessel_n with_o the_o water_n and_o bladder_n in_o the_o scale_n of_o a_o balance_n the_o say_a water_n weigh_v no_o more_o than_o if_o it_o want_v the_o bladder_n therefore_o the_o water_n become_v not_o heavy_a because_o the_o stone_n possess_v the_o room_n of_o 10_o pound_n of_o water_n but_o because_o the_o water_n sustain_v 10_o pound_n of_o the_o stone_n now_o the_o reason_n why_o the_o bladder_n make_v not_o the_o water_n heavy_a though_o it_o raise_v it_o from_o q_o r_o to_o m_o p_o be_v this_o because_o though_o very_o there_o be_v a_o great_a pressure_n than_o before_o even_o upon_o the_o bottom_n of_o the_o vessel_n yet_o because_o more_o part_n be_v not_o add_v the_o natural_a weight_n can_v be_v augment_v which_o essential_o depend_v upon_o the_o addition_n of_o these_o part_n if_o it_o be_v reply_v the_o experiment_n of_o the_o bladder_n be_v to_o no_o purpose_n because_o it_o be_v knit_v to_o the_o bottom_n pull_v up_o the_o vessel_n with_o as_o great_a force_n as_o the_o growth_n of_o the_o pressure_n bear_v it_o down_o and_o so_o the_o bladder_n can_v make_v the_o water_n heavy_a but_o if_o so_o be_v it_o be_v possible_a that_o the_o bladder_n can_v remain_v within_o the_o middle_n of_o the_o water_n without_o be_v knit_v to_o the_o bottom_n and_o consequent_o without_o pull_v up_o the_o vessel_n then_o sure_o the_o pillar_n of_o water_n m_o v_n and_o p_o x_o be_v high_a will_v press_v with_o great_a weight_n upon_o the_o bottom_n and_o so_o make_v the_o vessel_n and_o the_o water_n weigh_v more_o in_o the_o balance_n for_o it_o be_v to_o be_v suppose_v that_o during_o all_o this_o time_n this_o vessel_n with_o the_o water_n be_v in_o one_o scale_n and_o a_o great_a weight_n of_o stone_n or_o lead_v in_o the_o other_o so_o will_v the_o water_n a_o b_o c_o d_o become_v heavy_a likewise_o provide_v the_o space_n and_o room_n that_o the_o stone_n fill_v among_o the_o water_n remain_v entire_a after_o the_o stone_n be_v take_v away_o because_o that_o room_n and_o empty_a space_n remain_v will_v keep_v the_o surface_n as_o high_a as_o a_o b_o by_o which_o mean_n the_o pillar_n a_o c_o and_o b_o d_o be_v high_a will_v press_v with_o great_a weight_n upon_o the_o bottom_n and_o cause_v the_o water_n weigh_v more_o in_o the_o balance_n i_o answer_v though_o by_o some_o extraordinary_a power_n the_o bladder_n can_v remain_v below_o the_o water_n of_o its_o own_o accord_n as_o it_o be_v and_o though_o the_o space_n and_o room_n by_o that_o same_o power_n which_o be_v leave_v by_o the_o stone_n be_v keep_v empty_a yet_o shall_v they_o never_o be_v able_a to_o make_v the_o water_n heavy_a as_o to_o the_o reason_n that_o be_v bring_v i_o answer_v the_o rising_z and_o swell_v of_o the_o pillar_n will_v make_v indeed_o a_o great_a pressure_n upon_o the_o bottom_n of_o the_o vessel_n but_o because_o this_o pressure_n may_v be_v produce_v and_o generate_v without_o the_o addition_n of_o new_a part_n therefore_o it_o can_v never_o make_v the_o water_n heavy_a for_o if_o this_o be_v true_a than_o it_o will_v follow_v that_o the_o more_o a_o body_n be_v compress_v it_o shall_v be_v the_o heavy_a which_o be_v contrary_a to_o sense_n and_o experience_n this_o pressure_n be_v like_a unto_o bensil_n that_o can_v weigh_v in_o a_o balance_n though_o the_o thing_n bend_v do_v weigh_v as_o a_o bow_n that_o weigh_v so_o many_o pound_n but_o the_o bensil_n of_o it_o weigh_v nothing_o next_o will_v any_o man_n think_v that_o a_o cub_n of_o water_n six_o foot_n high_a and_o six_o foot_n thick_a will_v weigh_v more_o in_o a_o balance_n than_o it_o do_v after_o it_o be_v turn_v into_o a_o long_a square_a pillar_n 216_o inch_n high_a i_o grant_v there_o be_v near_o 60_o time_n a_o great_a pressure_n upon_o the_o bottom_n of_o the_o vessel_n yet_o because_o this_o pressure_n be_v generate_v without_o the_o addition_n of_o new_a part_n it_o can_v make_v the_o water_n heavy_a moreover_o it_o be_v mechanical_o possible_a to_o keep_v the_o water_n s_o t_o five_o x_o under_o that_o same_o degree_n of_o pressure_n it_o have_v though_o the_o rest_n above_o be_v take_v away_o if_o this_o be_v than_o it_o ought_v to_o be_v as_o heavy_a as_o the_o whole_a see_v it_o still_o press_v the_o bottom_n with_o that_o same_o degree_n of_o pressure_n it_o have_v from_o the_o whole_a but_o what_o be_v more_o absurd_a than_o to_o say_v one_o part_n of_o water_n be_v as_o heavy_a as_o the_o whole_a e._n g._n a_o pint_n as_o heavy_a as_o a_o gallon_n if_o it_o be_v say_v the_o pressure_n and_o the_o weight_n be_v but_o one_o thing_n at_o least_o effective_o which_o be_v sufficient_a to_o the_o purpose_n in_o hand_n as_o be_v clear_a from_o the_o theorem_fw-la 23._o i_o answer_v they_o be_v but_o one_o thing_n indeed_o in_o order_n to_o the_o balance_n of_o nature_n but_o they_o be_v neither_o formal_o nor_o effective_o the_o same_o thing_n in_o order_n to_o the_o libra_n or_o artificial_a balance_n whereof_o we_o be_v now_o treat_v i_o shall_v conclude_v with_o this_o while_o the_o vessel_n with_o the_o water_n be_v thus_o place_v in_o the_o scale_n of_o the_o balance_n and_o in_o equilibrio_n with_o the_o opposite_a scale_n cut_v the_o string_n that_o tie_v the_o bladder_n to_o the_o bottom_n and_o when_o it_o come_v above_o you_o will_v find_v the_o water_n just_a of_o the_o same_o weight_n it_o be_v of_o for_o though_o the_o surface_n m_o p_o by_o take_v out_o the_o bladder_n settle_v down_o to_o q_o r_o yet_o there_o be_v no_o alteration_n make_v in_o the_o weight_n from_o this_o i_o gather_v that_o if_o the_o swell_a of_o the_o water_n shall_v make_v it_o heavy_a than_o the_o subside_v and_o fall_v down_o of_o it_o aught_o to_o make_v it_o light_a from_o these_o experiment_n we_o gather_v first_o that_o in_o water_n there_o be_v a_o pressure_n because_o it_o sustain_v 10_o pound_n of_o the_o stone_n f_o g._n second_o that_o whatever_o heavy_a body_n be_v weigh_v in_o water_n it_o lose_v just_a as_o much_o of_o its_o weight_n as_o the_o bulk_n of_o water_n weigh_v it_o put_v out_o of_o its_o
fasten_v it_o to_o the_o bottom_n of_o the_o other_o glass_n at_o l._n next_o for_o sink_v the_o two_o glass_n take_v two_o weight_n of_o lead_n and_o fasten_v the_o one_o to_o the_o bottom_n at_o m_n and_o the_o other_o to_o the_o open_a part_n of_o the_o glass_n at_o saint_n and_o t._n the_o two_o weight_n then_o be_v p_o and_o q_o each_o one_o of_o they_o about_o 10_o or_o 12_o pound_n weight_n these_o thing_n be_v do_v let_v first_o down_o the_o glass_n g_o m_o till_o the_o weight_n q_o sink_v it_o five_o fathom_n namely_o from_o a_o to_o b_o and_o if_o you_o pull_v it_o up_o you_o will_v find_v the_o bottom_n cover_v with_o water_n from_o m_n to_o i_o about_o four_o or_o five_o inch_n let_v it_o down_o next_o from_o a_o to_o c_o ten_o fathom_n and_o you_o will_v find_v more_o water_n in_o it_o even_o as_o much_o as_o fill_v it_o from_o m_n to_o 2_o about_o seven_o or_o eight_o inch_n in_o pass_v from_o c_o d_o the_o water_n rise_v from_o 2_o to_o 3._o if_o you_o sink_v it_o from_o d_o to_z e_z the_o water_n rise_v from_o 3_o to_o 4._o the_o water_n rise_v from_o 4_o to_z 5_o when_o the_o glass_n be_v come_v the_o length_n of_o f._n and_o last_o when_o the_o glass_n be_v at_o g_o the_o low_a fathom_n the_o water_n be_v as_o high_a as_o k._n let_v down_o next_o the_o other_o glass_n from_o a_o to_o b_o and_o you_o will_v find_v the_o water_n rise_v in_o it_o from_o h_n to_o i_o four_o or_o five_o inch_n as_o in_o the_o other_o glass_n in_o go_v down_o from_o b_o to_z c_z it_z rises_z from_o 1_o to_o 2._o from_o c_z to_z d_o it_z rises_z from_o 2_o to_o 3._o from_o d_o to_z e_z it_z rises_z from_o 3_o to_z 4_o and_o so_o forward_o till_o the_o glass_n come_v to_o the_o low_a fathom_n where_o the_o water_n rise_v as_o high_a as_o i._n there_o be_v here_o several_a phenomena_n to_o be_v consider_v first_o that_o the_o water_n creep_v in_o at_o the_o orifice_n g_o and_o fill_v the_o under_o part_n of_o the_o glass_n from_o m_n to_o k._n second_o that_o not_o one_o particle_n of_o air_n come_v out_o all_o the_o time_n the_o water_n be_v in_o go_v in_o three_o that_o this_o air_n be_v compress_v from_o m_n to_o k_o nine_o inch_n last_o that_o the_o ingress_n of_o the_o water_n be_v according_a to_o unequal_a proportion_n because_o while_o the_o glass_n pass_v from_o a_o to_o b_o more_z water_n creep_v in_o at_o g_o and_o fill_v the_o bottom_n then_o in_o pass_v from_o b_o to_z c._n and_o more_o in_o go_v down_o from_o b_o to_z g_z than_o in_o go_v down_o from_o c_o to_o d_o as_o be_v clear_a from_o the_o unequal_a division_n 1_o 2_o 3_o 4_o 5_o 6_o for_o understand_v the_o reason_n of_o the_o first_o remember_v that_o in_o this_o deep_a water_n there_o be_v a_o pressure_n and_o that_o this_o pressure_n grow_v as_o the_o water_n grow_v in_o deepness_n it_o be_v then_o by_o virtue_n of_o this_o that_o the_o water_n creep_v in_o and_o fill_v the_o bottom_n of_o the_o vessel_n for_o in_o effect_n every_o part_n be_v under_o a_o burden_n and_o be_v therefore_o desirous_a to_o liberat_fw-la themselves_z from_o it_o they_o take_v occasion_n to_o thrust_v in_o themselves_o find_v as_o it_o be_v more_o ease_n here_o than_o without_o the_o air_n within_o the_o glass_n be_v under_o less_o pressure_n than_o the_o water_n without_o the_o second_o phenomenon_n be_v cause_v by_o the_o straitness_n and_o narrowness_n of_o the_o hole_n g_o for_o this_o entry_n be_v no_o wide_o than_o the_o thickness_n of_o a_o sack-needle_n the_o air_n can_v go_v out_o while_o the_o water_n be_v come_v in_o that_o be_v the_o passage_n be_v so_o straight_o that_o the_o one_o can_v go_v by_o the_o other_o this_o lead_v we_o to_o the_o reason_n of_o the_o three_o for_o if_o not_o one_o particle_n of_o air_n go_v out_o all_o the_o while_n the_o glass_n be_v in_o go_v down_o then_o sure_o the_o water_n fill_v between_o m_n and_o k_o must_v compress_v the_o air_n and_o reduce_v it_o from_o twelve_o inch_n to_o three_o but_o the_o great_a difficulty_n be_v why_o the_o ingress_n of_o the_o water_n be_v according_a to_o unequal_a proportion_n for_o understand_v this_o consider_v that_o this_o inequality_n be_v not_o cause_v by_o any_o unequal_a pressure_n that_o be_v in_o the_o water_n for_o if_o this_o be_v true_a then_o there_o ought_v to_o be_v less_o pressure_n in_o the_o surface_n f_o than_o in_o the_o surface_n e_o and_o less_o in_o e_o than_z in_o d_o which_o be_v false_a and_o absurd_a this_o inequality_n then_o must_v flow_v from_o the_o nature_n of_o the_o air_n itself_o that_o natural_o suffer_v compression_n after_o such_o a_o manner_n it_o be_v evident_a from_o the_o compression_n of_o air_n in_o wind-gun_n for_o less_o force_n be_v require_v to_o compress_v the_o first_o span_n than_o to_o compress_v the_o second_o or_o contrariwise_o more_o strength_n be_v require_v to_o compress_v the_o three_o span_n than_o the_o second_o more_o to_o compress_v the_o four_o than_o the_o three_o and_o so_o forth_o it_o be_v evident_a in_o all_o body_n endow_v with_o bensil_n as_o in_o the_o spring_n of_o a_o watch_n that_o require_v more_o strength_n to_o bend_v it_o in_o the_o end_n than_o in_o the_o beginning_n for_o a_o second_o trial_n pull_v up_o from_o the_o bottom_n of_o the_o water_n the_o glass_n l_o i_o h_o and_o when_o it_o come_v above_o you_o will_v find_v nothing_o in_o it_o the_o reason_n be_v because_o the_o vessel_n be_v open_a between_o t_n and_o s_o the_o whole_a water_n i_o h_n falls_z down_z by_o degree_n but_o in_o effect_n be_v real_o thrust_v out_o by_o the_o strong_a bensil_n of_o the_o compress_a air_n i_o l_o that_o now_o expand_v itself_o when_o it_o find_v the_o glass_n go_v up_o through_o the_o water_n who_o pressure_n be_v less_o and_o less_o from_o the_o bottom_n to_o the_o top_n but_o the_o contrary_a effect_n follow_v when_o the_o other_o glass_n be_v pull_v up_o namely_o the_o water_n remain_v within_o the_o glass_n and_o the_o air_n above_o it_o be_v thrust_v out_o by_o degree_n as_o the_o glass_n come_v near_a to_o the_o top_n for_o understand_v the_o reason_n of_o this_o consider_v first_o that_o while_o the_o orifice_n g_o be_v level_a with_o the_o low_a surface_n where_o it_o now_o be_v that_o be_v suppose_v to_o be_v 30_o fathom_n deep_a there_o be_v a_o real_a counterpoise_n between_o the_o enclose_a air_n g_o k_n and_o the_o ambient_fw-la water_n without_o for_o with_o what_o force_n the_o one_o strive_v to_o be_v in_o with_o the_o same_o force_n the_o other_o endeavour_n to_o be_v out_o and_o because_o they_o be_v in_o equal_a term_n therefore_o the_o one_o can_v yield_v to_o the_o other_o if_o you_o please_v to_o give_v the_o victory_n to_o the_o water_n then_o let_v the_o glass_n go_v further_o down_o but_o if_o you_o desire_v the_o air_n to_o overcome_v then_o must_v the_o glass_n be_v pull_v up_o pull_v it_o then_o up_o from_o the_o place_n it_o be_v in_o till_o it_o come_v to_o f_o and_o you_o will_v find_v a_o considerable_a quantity_n of_o air_n come_v out_o at_o g_o and_o after_o 2_o or_o 3_o minute_n of_o time_n emerge_n and_o come_v to_o the_o top_n a_o in_o form_n of_o round_a bell_n or_o bubble_n the_o deepness_n and_o groseness_n of_o the_o water_n through_o which_o the_o bubble_n come_v make_v their_o motion_n so_o slow_a the_o reason_n of_o this_o eruption_n must_v be_v less_o pressure_n of_o water_n in_o the_o surface_n f_o than_o in_o the_o low_a g_z from_o whence_o the_o glass_n come_v suppose_v then_o the_o low_a to_o have_v six_o degree_n of_o pressure_n f_o to_o have_v five_o e_z to_z have_v four_o d_o three_z c_z two_o and_o b_o to_o have_v one_o and_o suppose_v the_o enclose_a air_n k_o g_o to_o be_v equal_a in_o force_n to_o the_o pressure_n of_o the_o low_a fathom_n it_o must_v then_o have_v six_o degree_n of_o bensil_n in_o it_o put_v the_o case_n then_o that_o with_o six_o degree_n of_o bensil_n it_o come_v to_o the_o surface_n f_o that_o have_v but_o five_o it_o must_v sure_o break_v forth_o and_o overcome_v the_o force_n and_o power_n of_o that_o surface_n for_o it_o be_v impossible_a that_o two_o fluid_n can_v be_v unequal_a in_o force_n and_o power_n but_o the_o strong_a must_v overcome_v and_o the_o weak_a yield_v therefore_o when_o the_o orifice_n come_v to_o f_o the_o air_n be_v strong_a than_o the_o water_n break_v forth_o and_o as_o long_o do_v this_o eruption_n continue_v as_o inequality_n of_o power_n continue_v between_o the_o one_o and_o the_o other_o in_o pull_v up_o the_o glass_n from_o f_o to_o e_z other_z five_z fathom_n more_o
not_o contract_v itself_o no_o difference_n will_v happen_v but_o this_o be_v impossible_a so_o long_o as_o the_o water_n be_v under_o a_o pressure_n the_o expedient_a then_o must_v be_v find_v out_o another_o way_n namely_o by_o knit_n a_o small_a rope_n to_o the_o iron_n ring_n n_o in_o length_n with_o the_o other_o to_o which_o at_o certain_a distance_n relate_v to_o the_o fathom_n the_o ark_n go_v down_o must_v be_v fasten_v empty_a little_a vessel_n of_o wood_n or_o bladder_n which_o by_o their_o lightness_n may_v compense_v the_o decrement_n and_o decrease_v of_o the_o air._n first_o then_o let_v down_o the_o ark_n three_o fathom_n and_o see_v how_o much_o it_o be_v heavy_a than_o before_o and_o as_o you_o find_v the_o difference_n so_o fasten_v to_o r_o one_o bladder_n or_o two_o till_o the_o ark_n be_v bring_v near_o to_o a_o counterpoise_n second_o let_v it_o go_v down_o other_o three_o fathom_n and_o observe_v that_o difference_n also_o and_o according_o fasten_v to_o t_o as_o many_o as_o will_v reduce_v the_o two_o to_o a_o counterpoise_n again_o do_v after_o this_o manner_n till_o it_o sink_v 15_o or_o 20_o fathom_n it_o be_v to_o be_v observe_v that_o the_o further_o down_o the_o ark_n go_v the_o difference_n be_v the_o less_o therefore_o less_o addition_n will_v serve_v and_o the_o reason_n be_v because_o there_o be_v less_o air_n contract_v in_o pass_v between_o the_o five_o and_o the_o ten_o fathom_n than_o in_o pass_v from_o the_o first_o to_o the_o five_o the_o proportion_n of_o contraction_n be_v represent_v by_o the_o unequal_a division_n within_o the_o mouth_n of_o the_o ark_n as_o 1._o 2._o 3._o 4._o in_o a_o word_n by_o what_o proportion_n the_o decrement_n of_o the_o air_n be_v by_o that_o same_o proportion_n must_v the_o addition_n be_v upon_o the_o rope_n s_o n._n suppose_v then_o the_o air_n to_o be_v diminish_v four_o inch_n in_o go_v down_o four_o fathom_n which_o will_v be_v 5184_o square_a inch_n or_o three_o square_a foot_n then_o sure_o as_o much_o air_n must_v be_v add_v to_o the_o rope_n s_o n_o by_o bladder_n in_o go_v down_o as_o far_o let_v we_o suppose_v three-inche_n to_o be_v contract_v then_o less_o will_v suffice_v though_o it_o can_v be_v determine_v without_o trial_n how_o much_o air_n be_v contract_v in_o three_o fathom_n and_o how_o much_o in_o six_o and_o how_o much_o in_o nine_o yet_o this_o be_v sure_a that_o the_o decrease_a be_v according_a to_o unequal_a division_n that_o be_v to_o say_v less_o in_o six_o than_o in_o four_o less_o in_o 8_o than_o in_o six_o and_o less_o in_o 10_o than_o in_o 8_o and_o so_o downward_o and_o that_o this_o be_v the_o rule_n namely_o according_a to_o what_o quantity_n the_o air_n within_o the_o ark_n be_v contract_v according_a to_o that_o same_o measure_n must_v the_o addition_n of_o air_n be_v to_o the_o rope_n if_o it_o be_v say_v that_o bladder_n full_a of_o wind_n can_v go_v down_o through_o the_o water_n without_o burst_v i_o answer_v it_o be_v a_o mistake_n because_o their_o side_n be_v pliable_a and_o not_o stiff_a like_o the_o side_n of_o a_o timber_n vessel_n they_o yield_v and_o therefore_o can_v burst_v it_o be_v observable_a that_o when_o a_o bladder_n go_v far_o down_o the_o side_n become_v flaccid_a and_o flag_a in_o this_o case_n the_o air_n that_o before_o have_v the_o form_n of_o the_o bladder_n and_o be_v somewhat_o oval_a must_v now_o become_v perfect_o globular_a and_o round_o for_o it_o be_v sure_a that_o the_o dimension_n of_o it_o be_v alter_v by_o the_o pressure_n of_o the_o water_n namely_o from_o more_o quantity_n to_o less_o if_o this_o be_v than_o the_o form_n must_v be_v round_o see_v the_o pressure_n of_o the_o water_n be_v most_o uniform_a even_o as_o drop_n of_o water_n or_o rain_n from_o a_o house_n side_n be_v round_o upon_o this_o account_n this_o second_o way_n may_v be_v think_v upon_o also_o make_v the_o leaden_a footstool_n that_o sink_v the_o ark_n not_o of_o one_o piece_n but_o of_o many_o that_o so_o when_o the_o air_n within_o it_o begin_v to_o be_v contract_v by_o degree_n in_o go_v down_o a_o proportionable_a weight_n may_v be_v subtract_v for_o keep_v a_o just_a counterpoise_n all_o the_o while_n of_o the_o descent_n or_o because_o the_o great_a trouble_n be_v in_o bring_v of_o it_o up_o let_v the_o diver_n when_o once_o he_o be_v at_o the_o bottom_n subtract_v so_o much_o weight_n from_o the_o footstool_n as_o he_o think_v will_v go_v near_o to_o make_v a_o counterpoise_n at_o that_o deepness_n for_o example_n if_o the_o weight_n of_o the_o footstool_n be_v 40_o pound_n heavy_a than_o the_o ark_n then_o let_v he_o subtract_v 30_o or_o 36_o which_o may_v lie_v and_o rest_n upon_o the_o ground_n till_o it_o be_v draw_v up_o at_o a_o convenient_a time_n by_o a_o chord_n by_o his_o mean_n it_o will_v be_v easy_a to_o move_v the_o ark_n from_o one_o place_n to_o another_o next_o there_o shall_v be_v little_a or_o no_o difficulty_n to_o pull_v it_o up_o nay_o upon_o supposition_n the_o rope_n be_v break_v by_o which_o it_o be_v let_v down_o yet_o if_o the_o diver_n please_v he_o may_v come_v up_o without_o any_o man_n help_n and_o this_o be_v most_o easy_o do_v namely_o by_o subtract_v as_o much_o weight_n as_o will_v make_v the_o ark_n the_o strong_a party_n it_o be_v to_o be_v observe_v that_o when_o you_o be_v at_o the_o bottom_n and_o if_o you_o make_v the_o lead_n but_o one_o pound_n light_a than_o the_o ark_n it_o will_v sure_o come_v up_o and_o can_v stop_v by_o the_o way_n the_o reason_n be_v because_o a_o very_a small_a weight_n will_v turn_v the_o scale_n between_o two_o body_n thus_o weigh_v in_o water_n next_o the_o further_a the_o ark_n come_v up_o it_o become_v the_o light_a because_o the_o air_n within_o it_o expand_v itself_o the_o more_o but_o leave_v this_o let_v we_o come_v to_o explicat_fw-la the_o reason_n why_o the_o contraction_n of_o the_o air_n be_v not_o uniform_a but_o rather_o difform_v for_o if_o in_o go_v down_o three_o fathom_n three_o inch_n be_v contract_v there_o will_v not_o be_v other_o three_o contract_v in_o go_v down_o the_o second_o three_o but_o less_o and_o yet_o less_o in_o go_v down_o the_o three_o three_o two_o thing_n then_o be_v to_o be_v explicate_v here_o first_o why_o there_o be_v a_o contraction_n next_o why_o it_o be_v after_o such_o a_o manner_n as_o for_o the_o first_o the_o contraction_n be_v cause_v by_o the_o pressure_n of_o the_o water_n which_o gradual_o increase_v from_o the_o top_n to_o the_o bottom_n as_o be_v clear_a from_o the_o last_o experiment_n therefore_o there_o be_v a_o great_a pressure_n in_o a_o surface_n six_o fathom_n deep_a than_o in_o a_o surface_n three_o fathom_n deep_a the_o air_n within_o the_o ark_n must_v be_v more_o contract_v in_o pass_v between_o the_o three_o and_o six_o than_o in_o pass_v between_o the_o first_o and_o three_o when_o i_o say_v more_o contract_v the_o meaning_n be_v that_o more_o quantity_n be_v contract_v to_o less_o whereby_o the_o bensil_n of_o it_o be_v more_o intend_a or_o that_o the_o air_n be_v more_o bend_a as_o for_o the_o second_o we_o must_v remember_v from_o the_o last_o experiment_n that_o the_o cause_n of_o this_o be_v not_o from_o the_o water_n as_o if_o forsooth_o the_o pressure_n of_o it_o be_v according_a to_o unequal_a proportion_n but_o from_o the_o air_n itself_o who_o kind_n and_o nature_n it_o be_v to_o suffer_v compression_n after_o such_o a_o way_n it_o be_v evident_a in_o wind-gun_n who_o second_o span_n of_o air_n be_v compress_v with_o great_a difficulty_n than_o the_o first_o and_o the_o three_o with_o great_a difficulty_n than_o the_o second_o it_o be_v so_o with_o all_o body_n endow_v with_o benfil_v for_o ay_o the_o long_o you_o bend_v you_o find_v the_o great_a difficulty_n as_o there_o be_v a_o great_a disadvantage_n to_o the_o man_n that_o dives_n from_o the_o contraction_n of_o the_o air_n so_o there_o be_v a_o great_a advantage_n to_o he_o from_o this_o manner_n and_o way_n of_o contraction_n for_o if_o it_o be_v uniform_a according_a to_o the_o pressure_n of_o the_o water_n then_o if_o three_o fathom_n compress_v three_o inch_n six_o fathom_n ought_v to_o compress_v six_o inch_n nine_o fathom_n nine_o inch_n and_o so_o forward_o till_o by_o go_v down_o either_o the_o whole_a air_n shall_v be_v compress_v to_o no_o inch_n or_o else_o very_o little_o shall_v remain_v for_o respiration_n the_o next_o thing_n to_o be_v take_v notice_n of_o be_v that_o all_o the_o while_n during_o the_o down_o go_v of_o the_o ark_n there_o be_v still_o equality_n of_o weight_n between_o the_o pondus_fw-la of_o the_o water_n and_o the_o potentia_fw-la of_o the_o air_n for_o with_o what_o
that_o most_o easy_o observation_n viii_o there_o have_v be_v much_o inquiry_n make_v by_o some_o anent_o the_o reason_n why_o the_o dead_a body_n of_o a_o man_n or_o beast_n rise_v from_o the_o ground_n of_o a_o water_n after_o it_o have_v be_v there_o three_o or_o four_o day_n but_o though_o many_o have_v endeavour_v to_o solve_v the_o question_n yet_o the_o difficulty_n remain_v and_o in_o effect_v it_o can_v be_v answer_v without_o the_o knowledge_n of_o the_o forego_n doctrine_n anent_o the_o nature_n of_o fluid_a body_n to_o find_v out_o the_o reason_n then_o of_o this_o phenomenon_n consider_v that_o all_o body_n be_v either_o natural_o heavy_a than_o water_n as_o stone_n and_o lead_n or_o natural_o light_a as_o wood_n and_o timber_n if_o they_o be_v heavy_a they_o sink_v if_o they_o be_v light_a they_o swim_v now_o i_o say_v a_o man_n body_n immediate_o after_o he_o be_v drown_v his_o belly_n be_v full_a of_o water_n must_v go_v to_o the_o ground_n because_o in_o this_o case_n it_o will_v be_v find_v specifical_o or_o natural_o heavy_a than_o water_n that_o be_v to_o say_v a_o man_n body_n will_v be_v heavy_a than_o as_o much_o water_n as_o be_v the_o bulk_n of_o a_o man_n body_n for_o please_v the_o fancy_n imagine_v a_o statue_n to_o be_v compose_v of_o water_n with_o all_o the_o true_a dimension_n of_o the_o person_n that_o be_v dead_a so_o that_o the_o one_o shall_v answer_v most_o exact_o to_o all_o the_o dimension_n of_o the_o other_o in_o this_o case_n if_o you_o counterpoise_v they_o in_o a_o balance_n the_o real_a body_n that_o be_v make_v up_o of_o flesh_n blood_n and_o bone_n shall_v weigh_v down_o the_o other_o but_o after_o this_o dead_a body_n have_v lie_v a_o short_a time_n among_o the_o water_n it_o present_o begin_v to_o swell_v which_o be_v cause_v by_o the_o fermentation_n of_o the_o humour_n of_o the_o blood_n which_o go_v before_o putrefaction_n and_o after_o three_o or_o four_o day_n swell_v so_o great_a that_o in_o effect_n it_o become_v natural_o light_a than_o water_n and_o therefore_o rise_v that_o be_v to_o say_v take_v that_o body_n that_o be_v now_o swell_v and_o as_o much_o bulk_n of_o water_n as_o will_v be_v the_o precise_a quantity_n of_o it_o and_o have_v counterpoise_v they_o in_o a_o balance_n you_o will_v find_v the_o water_n heavy_a than_o the_o body_n observation_n ix_o upon_o thursday_n the_o 25_o of_o august_n 1670_o the_o follow_a experiment_n be_v make_v in_o a_o new_a coal-sink_a on_o the_o west_n side_n of_o tranent_n when_o the_o coal-hewers_a have_v dig_v down_o about_o 6_o or_o 7_o fathom_n they_o be_v interrupt_v sometime_o with_o ill_a air_n therefore_o to_o know_v the_o power_n and_o force_v of_o the_o damp_n we_o let_v down_o within_o the_o bucket_n a_o dog_n when_o he_o have_v go_v down_o about_o 4_o fathom_n or_o middle_a sink_n we_o find_v little_a or_o no_o alteration_n in_o he_o save_v only_o that_o he_o open_v his_o mouth_n and_o have_v some_o difficulty_n in_o breathe_v which_o we_o perceive_v evident_o for_o no_o soon_o he_o be_v pull_v up_o to_o the_o top_n where_o the_o good_a air_n be_v but_o he_o leave_v off_o his_o gape_n we_o let_v he_o down_o next_o to_o the_o bottom_n where_o he_o tarry_v a_o pretty_a while_n but_o no_o more_o change_n we_o find_v in_o he_o than_o before_o after_o this_o we_o let_v down_o a_o great_a quantity_n of_o whin_n well_o kindle_v with_o a_o bold_a flame_n but_o they_o no_o soon_o come_v to_o the_o middle_n of_o the_o sink_n but_o the_o flame_n be_v in_o a_o instant_n extinguish_v and_o no_o soon_o be_v the_o bucket_n pull_v up_o but_o they_o take_v fire_n again_o this_o be_v 5_o or_o 6_o time_n try_v with_o the_o same_o success_n if_o we_o compare_v this_o observation_n with_o the_o first_o we_o will_v find_v that_o all_o damp_n be_v not_o of_o the_o same_o power_n and_o force_n but_o that_o some_o be_v strong_a and_o kill_v man_n and_o beast_n in_o a_o instant_n and_o that_o other_o be_v less_o efficacious_a and_o more_o feeble_a and_o do_v not_o so_o much_o hurt_v and_o that_o man_n may_v hazard_v to_o go_v down_o into_o a_o sink_v where_o ill_a air_n be_v even_o though_o fire_n be_v sometime_o extinguish_v we_o see_v next_o that_o these_o damp_n do_v not_o always_o infect_v the_o whole_a air_n of_o a_o coal-pit_n but_o only_o a_o certain_a quantity_n for_o sometime_o it_o be_v find_v in_o the_o bottom_n sometime_o in_o the_o middle_n and_o we_o see_v last_o that_o they_o be_v not_o always_o of_o long_a continuance_n for_o it_o be_v find_v that_o though_o the_o air_n be_v ill_a in_o the_o morning_n yet_o it_o may_v be_v good_a ere_o night_n and_o total_o evanish_v ere_o the_o next_o day_n we_o may_v add_v as_o be_v note_v in_o the_o first_o observation_n that_o these_o damp_n depend_v much_o upon_o the_o situation_n of_o the_o wind_n see_v in_o strong_a southerly_a wind_n they_o be_v frequent_o in_o these_o place_n observation_n x._o of_o these_o many_o excellent_a device_n that_o have_v be_v find_v out_o of_o late_a the_o air-pump_n be_v one_o first_o invent_v in_o germany_n and_o afterward_o much_o perfect_v in_o england_n by_o that_o honourable_a person_n mr_n boyl_n who_o for_o his_o pain_n and_o industry_n in_o make_v experiment_n therewith_o deserve_v the_o thanks_o of_o all_o learned_a person_n several_a trial_n have_v be_v make_v of_o late_a by_o it_o some_o whereof_o be_v as_o follow_v i_o take_v a_o slender_a glass-tub_n about_o 40_o inch_n long_o close_o above_o and_o open_v below_o and_o fill_v it_o with_o water_n i_o next_o invert_v it_o and_o set_v the_o orifice_n of_o it_o just_a upon_o the_o mouth_n of_o the_o brass-pipe_n that_o bend_v upward_o through_o the_o board_n whereon_o the_o receiver_n use_v to_o stand_v and_o cement_v they_o together_o at_o the_o first_o exsuction_n the_o whole_a water_n in_o the_o pipe_n fall_v down_o and_o run_v through_o the_o brass-conduit_n to_o the_o pump_n have_v for_o a_o short_a while_n stop_v the_o passage_n and_o thrust_v down_o the_o sucker_n i_o next_o open_v it_o again_o and_o the_o pump_n be_v full_a of_o water_n it_o be_v drive_v with_o a_o considerable_a force_n up_o through_o the_o pipe_n yet_o be_v it_o not_o complete_o fill_v as_o before_o by_o reason_n of_o some_o air_n that_o i_o see_v in_o the_o top_n after_o this_o be_v do_v with_o pleasure_n five_o or_o six_o time_n i_o open_v the_o stop-cock_n more_o quick_o than_o i_o have_v use_v but_o the_o water_n by_o this_o mean_n be_v so_o furious_o drive_v up_o through_o the_o tub_n that_o in_o effect_n it_o break_v the_o end_n of_o it_o that_o be_v hermetical_o seal_v and_o the_o piece_n that_o fly_v off_o do_v hit_v the_o seiling_n so_o smart_o that_o it_o rebound_v a_o very_a far_a way_n from_o this_o we_o see_v the_o reason_n why_o water_n fall_v not_o down_o from_o vessel_n that_o have_v narrow_a neck_n though_o they_o be_v invert_v because_o it_o be_v keep_v in_o by_o the_o force_n and_o power_n of_o the_o environ_v air._n it_o be_v observable_a that_o though_o this_o pipe_n have_v be_v 30_o foot_n high_a yet_o the_o whole_a water_n in_o it_o will_v have_v subside_v and_o fall_v down_o with_o one_o exsuction_n the_o next_o trial_n be_v with_o the_o help_n of_o a_o small_a receiver_n which_o in_o effect_n be_v a_o real_a cupping-glass_n this_o have_v a_o hole_n make_v in_o the_o bottom_n of_o it_o and_o be_v cement_v to_o the_o brass-plate_n and_o the_o mouth_n of_o it_o look_v upward_o have_v a_o lid_n for_o cover_v of_o it_o i_o take_v next_o the_o late_o mention_v glass-pipe_n and_o fill_v it_o with_o good_a brandy_n and_o have_v drown_v the_o end_n of_o it_o among_o stagnant_a brandy_n i_o set_v the_o vessel_n wherein_o it_o be_v within_o the_o receiver_n the_o pipe_n come_v up_o through_o the_o lid_n and_o have_v cement_v it_o close_o i_o make_v the_o first_o exsuction_n and_o find_v no_o descent_n of_o the_o liquor_n from_o the_o top_n of_o the_o tub._n at_o the_o second_o it_o fall_v down_o about_o a_o inch_n at_o the_o three_o it_o fall_v down_o four_o or_o five_o but_o here_o appear_v a_o great_a multitude_n of_o small_a bubble_n of_o air_n like_o break_a water_n near_o the_o top_n of_o the_o pipe_n within_o and_o beside_o this_o phenomenon_n there_o ascend_v from_o the_o stagnant_a liquor_n up_o through_o the_o pipe_n a_o infinite_a number_n of_o small_a bubble_n no_o big_a than_o pin-head_n for_o a_o very_a large_a time_n with_o a_o four_o exsuction_n it_o fall_v down_o within_o two_o or_o three_o inch_n of_o the_o stagnant_a brandy_n and_o think_v to_o make_v the_o one_o level_v with_o the_o other_o i_o make_v a_o five_o but_o here_o appear_v a_o strange_a effect_n namely_o
where_o four_o mill_n go_v with_o the_o water_n that_o come_v from_o under_o ground_n out_o of_o the_o coal_n which_o kind_n of_o level_n be_v only_o find_v where_o the_o coal_n lie_v in_o a_o field_n which_o have_v a_o considerable_a rise_n or_o ascent_n above_o ground_n there_o be_v a_o necessity_n to_o make_v use_n of_o the_o other_o two_o way_n speak_v of_o for_o dry_v the_o coal_n when_o the_o field_n in_o which_o it_o lie_v be_v a_o plain_n further_o of_o these_o coal_n which_o be_v dry_v by_o the_o free-level_n for_o so_o they_o term_v the_o level_n that_o run_v unforced_a there_o be_v some_o to_o which_o this_o kind_n of_o damp_n be_v more_o incident_a than_o to_o other_o the_o cause_n of_o which_o difference_n be_v find_v to_o be_v the_o solidity_n and_o clossness_n of_o the_o metal_n whether_o of_o coal_n or_o stone_n wherein_o some_o exceed_v another_o there_o be_v some_o that_o be_v full_a of_o rift_n or_o empty_a space_n i_o mean_v empty_a of_o any_o part_n of_o the_o same_o body_n where_o they_o be_v which_o will_v sometime_o serve_v to_o convey_v a_o considerable_a quantity_n of_o water_n in_o place_n of_o a_o aquaduct_a or_o level_a which_o space_n be_v term_v by_o the_o vulgar_a cutter_n which_o sometimes_o prove_v very_o profitable_a in_o the_o ground_n where_o they_o be_v find_v both_o in_o regard_n of_o the_o use_n they_o serve_v for_o in_o stead_n of_o level_n and_o for_o render_v the_o metal_n wherein_o they_o be_v find_v more_o easy_a to_o work_v in_o make_v they_o yield_v easy_o to_o the_o force_n of_o the_o wedge_n and_o leaver_n other_o metal_n there_o be_v wherein_o few_o of_o these_o cutter_n be_v to_o be_v find_v and_o if_o water_n be_v to_o be_v convey_v through_o they_o there_o be_v a_o necessity_n of_o cut_v a_o passage_n through_o they_o for_o that_o effect_n now_o this_o damp_n whereof_o we_o speak_v be_v find_v most_o frequent_o and_o most_o violent_a in_o the_o first_o sort_n of_o metal_n viz._n in_o these_o which_o be_v full_a of_o cutter_n or_o rift_n which_o give_v some_o ground_n to_o this_o conjecture_n of_o its_o cause_n these_o space_n which_o be_v find_v in_o coal_n or_o other_o metal_n as_o stone_n or_o till_n before_o the_o coal_n begin_v to_o be_v dry_v by_o a_o level_n be_v full_a of_o water_n which_o be_v still_o in_o motion_n as_o be_v all_o subterraneous_a spring_n whereof_o some_o be_v more_o violent_a some_o more_o slow_a conform_v to_o the_o passage_n they_o have_v to_o the_o fountain_n above_o ground_n where_o they_o discharge_v themselves_o now_o for_o dry_v these_o coal_n and_o render_v they_o workable_a there_o be_v a_o necessity_n to_o cut_v a_o passage_n through_o which_o that_o water_n discharge_v itself_o quick_o it_o be_v large_a and_o admit_v a_o great_a quantity_n at_o once_o by_o virtue_n whereof_o a_o great_a field_n be_v drain_v at_o once_o and_o the_o source_n not_o be_v able_a to_o furnish_v so_o much_o water_n as_o the_o conduit_n be_v able_a to_o convey_v these_o space_n in_o the_o body_n of_o the_o metal_n be_v empty_v of_o water_n must_v needs_o be_v fill_v with_o air_n which_o air_n have_v little_a contact_n and_o commerce_n with_o the_o great_a body_n of_o air_n above_o ground_n and_o so_o have_v little_a or_o â—o_o motion_n corrupt_v in_o these_o place_n and_o thereby_o become_v poisonable_a so_o that_o when_o any_o animal_n be_v necessitat_fw-la to_o draw_v it_o and_o respire_v by_o it_o it_o choke_v they_o on_o a_o sudden_a just_a as_o stand_a water_n which_o be_v without_o motion_n corrupt_v and_o become_v poisonable_a though_o haply_o not_o in_o so_o great_a a_o degree_n as_o the_o air_n the_o air_n be_v a_o body_n much_o â—iner_a and_o pure_a than_o water_n that_o hold_v good_a in_o it_o corruptio_fw-la optimi_fw-la pessima_fw-la this_o be_v much_o confirm_v by_o what_o be_v before_o assert_v that_o in_o the_o coal_n whence_o the_o water_n be_v draw_v and_o they_o drain_v but_o not_o by_o free-course_n but_o by_o force_n as_o pump_v and_o draw_v by_o bucket_n these_o damp_n be_v seldom_o or_o never_o find_v because_o the_o passage_n of_o the_o water_n be_v force_v it_o do_v not_o so_o sudden_o dry_v the_o metal_n as_o the_o other_o whereby_o there_o be_v always_o leave_v in_o these_o space_n some_o water_n which_o be_v itself_o in_o motion_n keep_v the_o air_n also_o in_o motion_n with_o it_o and_o thereby_o the_o air_n be_v keep_v from_o corruption_n at_o least_o in_o such_o a_o degree_n as_o it_o be_v in_o the_o other_o hence_o we_o find_v that_o in_o these_o kind_n of_o coal_n the_o room_n underground_o be_v always_o wet_a or_o for_o the_o most_o part_n they_o be_v so_o whereas_o in_o the_o other_o there_o will_v be_v no_o water_n find_v to_o wash_v a_o man_n hand_n and_o sometime_o the_o coal_n through_o want_n of_o water_n become_v so_o dry_a that_o it_o can_v be_v wrought_v in_o great_a piece_n as_o other_o but_o crush_v in_o the_o very_a work_n and_o when_o wrought_v be_v render_v useless_a and_o will_v not_o at_o all_o bourn_n this_o put_v i_o in_o mind_n of_o a_o very_a pleasant_a conception_n of_o a_o worthy_a and_o learned_a person_n doctor_n george_n hepburn_n of_o monk-ridge_n with_o who_o i_o have_v occasion_n one_o day_n to_o discourse_n on_o this_o subject_a he_o be_v of_o opinion_n that_o the_o water_n be_v the_o mother_n of_o the_o coal_n whereby_o it_o be_v preserve_v fresh_a and_o incorrupt_v and_o that_o when_o the_o water_n be_v draw_v off_o and_o this_o damp_n follow_v it_o be_v not_o the_o air_n which_o succeed_v in_o place_n of_o the_o water_n and_o be_v corrupt_v for_o want_n of_o motion_n that_o occasion_n it_o but_o as_o we_o see_v when_o the_o corruption_n of_o a_o liquor_n within_o a_o vessel_n when_o the_o mother_n be_v go_v corrupt_v the_o vessel_n itself_o and_o occasion_n a_o ill_a savour_n or_o taste_v in_o the_o vessel_n so_o that_o the_o coal_n be_v corrupt_v by_o the_o want_n of_o its_o mother_n the_o water_n corrupt_v the_o air_n in_o the_o subterraneous_a space_n as_o in_o coal-mine_n sink_n cave_n and_o other_o such_o like_a he_o have_v likewise_o another_o pleasant_a conception_n about_o the_o generation_n of_o coal_n judge_v it_o to_o be_v form_v gradual_o out_o of_o another_o metal_n as_o of_o till_n by_o the_o help_n of_o water_n of_o which_o he_o himself_o may_v perhaps_o give_v a_o account_n and_o though_o i_o be_v not_o of_o his_o opinion_n in_o that_o matter_n yet_o i_o must_v acknowledge_v i_o be_v take_v with_o it_o and_o shall_v be_v glad_a to_o see_v a_o more_o full_a account_n of_o it_o from_o he_o than_o he_o have_v access_n to_o do_v in_o the_o short_a conference_n we_o have_v the_o effect_n of_o this_o damp_n be_v first_o it_o hinder_v the_o burn_a of_o all_o combustible_a matter_n as_o candle_n coal_n pitch_n sulphur_n etc._n etc._n so_o that_o if_o you_o take_v a_o torch_n light_v and_o let_v it_o down_o to_o a_o sink_v where_o the_o ill_a air_n be_v prevalent_a in_o the_o time_n it_o shall_v straightway_o extinguish_v it_o or_o take_v a_o coal_n which_o be_v burn_v and_o let_v it_o down_o it_o shall_v not_o only_o extinguish_v the_o flame_n but_o shall_v make_v the_o coal_n in_o a_o instant_n dead_a and_o as_o cold_a as_o never_o heat_n have_v be_v in_o it_o but_o the_o most_o dangerous_a effect_n be_v its_o kill_v of_o live_a creature_n whereby_o many_o person_n have_v be_v sudden_o kill_v some_o in_o go_v down_o to_o a_o sink_v where_o it_o have_v be_v powerful_a have_v fall_v out_o of_o the_o rope_n and_o perish_v other_o have_v be_v choke_v and_o yet_o have_v get_v out_o by_o the_o help_n of_o other_o in_o a_o sudden_a and_o have_v remain_v a_o considerable_a time_n without_o the_o least_o appearance_n of_o life_n but_o yet_o have_v at_o last_o recover_v yet_o it_o have_v be_v observe_v that_o some_o of_o these_o person_n that_o have_v be_v so_o strike_v with_o the_o damp_n and_o recover_v have_v have_v always_o some_o lightness_n of_o brain_n thereafter_o and_o never_o so_o settle_v as_o former_o this_o i_o know_v to_o have_v happen_v to_o one_o who_o i_o have_v see_v so_o many_o time_n thereafter_o what_o have_v be_v its_o effect_n on_o some_o animal_n whereof_o you_o have_v make_v experiment_n i_o leave_v to_o the_o account_n you_o have_v give_v one_o thing_n i_o shall_v only_o mention_v which_o to_o i_o seem_v somewhat_o strange_a that_o notwithstanding_o these_o damp_n be_v so_o effectual_a and_o cause_v so_o sudden_o the_o death_n of_o animal_n yet_o the_o rat_n which_o be_v in_o some_o of_o these_o place_n where_o the_o damp_n be_v most_o violent_a be_v not_o reach_v by_o they_o for_o sometime_o when_o they_o be_v so_o powerful_a that_o nothing_o that_o life_n can_v enter_v under_o ground_n
crop_n of_o the_o metal_n the_o body_n whereof_o lie_v in_o it_o whether_o of_o coal_n or_o stone_n in_o that_o case_n there_o be_v no_o way_n to_o try_v but_o by_o sink_v or_o boar_v the_o way_n of_o range_v be_v conspicuous_a in_o the_o follow_a figure_n figure_n 11._o the_o piece_n of_o ground_n to_o be_v try_v be_v p_o n_o where_o there_o be_v several_a seam_n of_o metal_n that_o crop_n out_o at_o the_o point_n k_o l_o m_o n._n suppose_v the_o low_a to_o be_v the_o coal_n viz._n i_o n_o for_o which_o you_o be_v to_o make_v trial_n you_o dig_v first_o at_o k_o without_o the_o cropp_n of_o the_o seam_n f_o k_n and_o you_o dig_v till_o you_o find_v the_o other_o seam_n of_o stone_n g_o l_o at_o the_o point_n c._n follow_v the_o rule_n before_o give_v you_o advance_v before_o its_o crop_n and_o dig_v at_o l_o and_o find_v the_o other_o seam_n of_o stone_n h_n m_o at_o the_o point_n d_o from_o which_o you_o also_o advance_v and_o dig_v before_o its_o crop_n at_o the_o point_n m_o and_o find_v your_o coal_n at_o the_o point_n e._n but_o if_o by_o advance_v over_o the_o crop_n of_o these_o metal_n which_o come_v out_o from_o under_o one_o another_o you_o find_v no_o coal_n than_o you_o be_v to_o range_v backward_o for_o the_o crop_n of_o metal_n lie_v above_o these_o where_o haply_o the_o coal_n may_v be_v as_o at_z o_o and_o p._n this_o in_o my_o opinion_n be_v the_o most_o certain_a and_o exact_a way_n of_o try_v field_n for_o coal_n or_o any_o other_o metal_n of_o that_o nature_n and_o least_o chargeable_a of_o all_o other_o the_o second_o of_o this_o last_o part_n i_o promise_v to_o speak_v of_o be_v in_o order_n to_o level_n or_o coal-mine_n which_o be_v nothing_o else_o but_o conduit_n or_o gutter_n make_v under_o ground_n for_o convey_v of_o the_o water_n from_o the_o coal_n and_o so_o render_v it_o workable_a it_o seem_v that_o a_o very_a little_a time_n before_o this_o that_o way_n of_o mine_a under_o ground_n have_v not_o be_v fall_v upon_o for_o there_o be_v to_o be_v find_v coal_n waste_v in_o their_o crop_n only_o for_o convey_v the_o water_n whereof_o they_o have_v make_v a_o conduit_n or_o level_v which_o have_v be_v open_a to_o the_o surface_n like_o a_o great_a ditch_n some_o whereof_o have_v be_v ten_o or_o twelve_o fathom_n in_o their_o deepness_n the_o beginning_n of_o the_o level_n to_o keep_v the_o term_n use_v must_v always_o be_v at_o the_o low_a part_n of_o the_o field_n where_o the_o coal_n lie_v to_o be_v dry_v some_z whereof_o by_o the_o rise_n of_o the_o ground_n and_o the_o streek_a of_o the_o coal_n rise_v that_o way_n as_o we_o show_v before_o give_v the_o advantage_n of_o a_o free_a level_n that_o be_v when_o the_o water_n come_v above_o ground_n of_o its_o own_o accord_n without_o be_v force_v by_o draw_v in_o other_o there_o be_v a_o necessity_n of_o engine_n to_o draw_v the_o water_n from_o the_o low_a part_n of_o the_o level_n and_o bring_v it_o above_o ground_n which_o engine_n be_v of_o several_a sort_n as_o when_o man_n draw_v with_o ordinary_a bucket_n or_o when_o there_o be_v a_o horse-work_n or_o waterwork_n and_o that_o either_o by_o a_o chain_n with_o plate_n and_o a_o pump_n or_o with_o a_o chain_n and_o bucket_n all_o which_o be_v very_o common_a especial_o those_o we_o have_v in_o scotland_n they_o be_v capable_a to_o draw_v but_o a_o very_a small_a draught_n make_v only_a use_n of_o one_o sink_v for_o that_o effect_n but_o there_o be_v to_o be_v see_v in_o the_o north_n of_o england_n in_o bishopric_n water-work_n by_o which_o water_n be_v draw_v above_o 40_o fathom_n in_o perpendicular_a but_o not_o all_o in_o one_o sink_n the_o manner_n whereof_o be_v thus_o there_o be_v a_o sink_v from_o the_o end_n of_o their_o level_n to_o the_o surface_n of_o the_o earth_n where_o their_o work_n be_v go_v 40_o fathom_n deep_a which_o must_v dry_v the_o coal-sinks_n at_o 60_o or_o 70_o which_o lie_v above_o the_o bank_n of_o the_o river_n where_o the_o water-work_n be_v situate_v there_o be_v first_o one_o 40_o fathom_n deep_a from_o the_o grass_n another_o in_o a_o right_a line_n from_o that_o of_o 24._o another_o of_o 12_o upon_o all_o which_o there_o be_v water-work_n in_o the_o first_o sink_v the_o water_n be_v draw_v from_o the_o bottom_n 12_o fathom_n and_o thence_o convey_v into_o a_o level_n or_o i_o which_o carry_v it_o away_o to_o the_o second_o sink_v by_o the_o second_o â—ork_n the_o water_n be_v draw_v out_o of_o the_o second_o sink_v 14_o fathom_n from_o the_o bottom_n and_o set_v in_o by_o a_o level_n to_o the_o three_o sink_v which_o be_v only_o 12_o fathom_n deep_a the_o waterwork_n set_v it_o above_o ground_n the_o form_n of_o the_o engine_n be_v after_o this_o manner_n in_o the_o first_o sink_v there_o be_v a_o outter-wheel_n move_v as_o other_o milns_n be_v by_o the_o water_n of_o the_o river_n upon_o the_o end_n of_o the_o axletree_n of_o which_o wheel_n there_o be_v a_o ragg-wheel_n turn_v vertical_o as_o do_v the_o outer-wheel_n this_o ragg-wheel_n by_o a_o nutt_n or_o trinle_n turn_v another_o which_o move_v horizontal_o the_o axletree_n whereof_o go_v right_o down_o in_o the_o sink_v and_o may_v be_v be_v 8_o or_o 10_o fathom_n at_o the_o end_n whereof_o there_o be_v another_o rag_n which_o by_o a_o nutt_n turn_v another_o wheel_n which_o go_v vertical_o as_o the_o first_o rag_n and_o cause_v another_o wheel_n with_o a_o long_a axletree_n turn_v as_o the_o first_o and_o so_o down_o till_o it_o come_v to_o the_o wheel_n which_o turn_v the_o axletree_n by_o which_o the_o chain_n be_v draw_v the_o second_o sink_v have_v such_o another_o engine_n but_o not_o so_o many_o wheel_n in_o regard_n it_o be_v not_o so_o deep_a the_o three_o have_v only_o one_o single_a wheel_n whereby_o the_o water_n be_v draw_v above_o ground_n the_o most_o curious_a of_o these_o engine_n that_o be_v to_o be_v see_v be_v at_o ravensworth_n near_o to_o newcastle_n which_o belong_v to_o sir_n thomas_n liddel_n a_o most_o ingenious_a gentleman_n who_o for_o procure_v a_o fall_n of_o water_n which_o may_v serve_v the_o wheel_n of_o all_o the_o three_o sink_n have_v erect_v the_o first_o work_n upon_o pillar_n like_o a_o windmill_n pretty_a high_a above_o ground_n from_o which_o the_o water_n fall_v make_v the_o second_o go_v close_o above_o ground_n and_o to_o make_v the_o water_n fall_v to_o the_o three_o the_o whole_a wheel_n be_v make_v go_v within_o the_o surface_n of_o the_o ground_n which_o terminat_n at_o a_o river_n under_o the_o work_n which_o mine_n be_v of_o a_o considerable_a length_n where_o water_n can_v be_v have_v to_o make_v such_o work_v go_v they_o use_v horse-work_n but_o not_o wâ—th_o so_o good_a success_n be_v more_o chargeable_a and_o not_o have_v so_o much_o force_n and_o power_n as_o the_o water-work_n but_o i_o be_o of_o opinion_n that_o wind-work_n may_v serve_v well_o where_o water_n can_v be_v have_v and_o when_o no_o wind_n shall_v happen_v to_o blow_v the_o same_o work_n may_v be_v supply_v by_o horse_n and_o that_o the_o wind_n when_o it_o blow_v but_o ordinary_o have_v as_o much_o force_n as_o so_o much_o water_n which_o be_v make_v use_n of_o for_o turn_v such_o wheel_n be_v to_o i_o unquestionable_a for_o i_o have_v see_v in_o holland_n a_o windmill_n that_o by_o the_o motion_n of_o the_o outter-wheel_n cause_v seven_o pair_n of_o millstone_n to_o go_v at_o once_o beside_o another_o motion_n for_o bring_v the_o victual_n from_o the_o ground_n four_o or_o five_o story_n high_a to_o be_v grund_n and_o several_a saw-mill_n which_o beside_o six_o or_o seven_o great_a saw_n they_o cause_v go_v do_v by_o another_o motion_n bring_v up_o from_o the_o water_n great_a tree_n like_o ship-mast_n to_o be_v fawen_v and_o place_v they_o right_o against_o the_o saw_n all_o which_o can_v not_o be_v but_o of_o great_a weight_n than_o 10_o or_o 12_o fathom_n of_o chain_n with_o bucket_n or_o plate_n for_o draw_v of_o water_n but_o to_o return_v for_o the_o right_n make_v of_o a_o level_n the_o true_a height_n of_o the_o ground_n where_o the_o coal_n lie_v must_v be_v first_o take_v that_o it_o may_v be_v know_v how_o much_o of_o the_o field_n can_v be_v drain_v by_o it_o which_o must_v be_v do_v either_o with_o a_o quadrant_n or_o with_o a_o instrument_n make_v express_v then_o care_n must_v be_v take_v to_o take_v the_o low_a part_n for_o the_o mouth_n of_o the_o level_n that_o the_o field_n can_v afford_v and_o from_o that_o it_o must_v be_v carry_v in_o a_o straight_a line_n towards_o that_o part_n of_o the_o field_n where_o the_o coal_n be_v think_v to_o be_v encounter_v by_o the_o mine_n in_o work_v
that_o be_v specifical_o or_o natural_o light_a than_o water_n i_o say_v then_o it_o must_v ascend_v to_o the_o top_n b_o and_o the_o reason_n be_v because_o the_o quadrat_fw-la foot_n of_o water_n k_o be_v more_o press_v upward_o than_o the_o quadrat_fw-la foot_n of_o water_n i_o or_o l_o be_v but_o this_o can_v be_v iâ—_n fluid_a body_n unless_o motion_n follow_v thereupon_o i_o say_v it_o be_v more_o press_v up_o because_o r_o be_v light_a than_o n_o or_o saint_n it_o must_v press_v with_o great_a force_n upon_o k_o than_o saint_n can_v do_v upon_o l_o or_o n_o upon_o i._o it_o be_v still_o to_o be_v remember_v that_o fluids_n press_v with_o as_o much_o strength_n upward_o as_o downward_o according_a to_o the_o six_o theorem_n and_o that_o a_o horizontal_n surfaceâ—doth_a as_o real_o suffer_v unequal_a pressure_n from_o below_o as_o from_o above_z theorem_fw-la fourteen_o body_n natural_o light_a than_o water_n swim_v upon_o the_o surface_n and_o top_n figure_n 1._o the_o reason_n of_o this_o proposition_n must_v be_v take_v from_o the_o nature_n of_o a_o equipondium_fw-la or_o equal_a weight_n for_o without_o doubt_n there_o be_v a_o counterbalance_n between_o the_o pressure_n of_o the_o water_n and_o the_o weight_n of_o the_o body_n that_o swim_v to_o make_v this_o probable_a let_v we_o suppose_v there_o be_v a_o piece_n of_o timber_n in_o form_n of_o a_o cube_n six_o inch_n thick_a every_o way_n without_o weight_n in_o this_o case_n the_o undersurface_n of_o that_o foursquared_a body_n be_v apply_v to_o the_o surface_n of_o the_o water_n a_o will_v lie_v close_o upon_o it_o as_o one_o plain_a table_n lie_v upon_o the_o face_n of_o another_o without_o any_o pressure_n and_o it_o be_v void_a of_o weight_n the_o part_n of_o the_o surface_n a_o will_v be_v no_o more_o burden_v than_o the_o next_o part_n b_o adjacent_a whence_o no_o motion_n will_v follow_v here_o be_v no_o equipondium_fw-la or_o counterbalance_n second_o let_v we_o suppose_v the_o say_a body_n to_o acquire_v two_o ounce_n of_o weight_n than_o it_o follow_v that_o it_o must_v subside_o and_o sink_v two_o inch_n below_o the_o surface_n a_o b_o c_o d_o and_o that_o so_o far_o till_o it_o come_v by_o virtue_n of_o its_o new_a acquire_v weight_n to_o a_o counterbalance_n with_o the_o pressure_n of_o the_o water_n which_o pressure_n be_v nothing_o else_o but_o as_o much_o force_n or_o weight_n as_o be_v equivalent_a to_o the_o weight_n of_o water_n that_o be_v thrust_v out_o of_o its_o own_o place_n by_o the_o subside_v and_o sink_v of_o that_o body_n two_o inch_n three_o let_v we_o suppose_v the_o same_o body_n to_o acquire_v other_o two_o ounce_n of_o weight_n then_o must_v it_o subside_o other_o two_o inch_n last_o let_v we_o suppose_v that_o it_o acquire_v six_o ounce_n of_o weight_n than_o it_o follow_v that_o the_o whole_a body_n sink_v so_o far_o i_o mean_v till_o its_o upmost_a surface_n be_v in_o a_o horizontal_n line_n with_o the_o surface_n of_o the_o water_n a_o b_o c_o d._n here_o it_o swim_v also_o because_o the_o weight_n of_o it_o become_v just_a the_o weight_n of_o so_o much_o water_n as_o it_o have_v put_v out_o of_o its_o own_o place_n i_o say_v it_o must_v swim_v because_o if_o the_o water_n i_o be_v able_a to_o sustain_v the_o water_n e_o which_o be_v put_v from_o its_o own_o place_n sure_o it_o must_v be_v able_a to_o sustain_v that_o body_n also_o that_o do_v thrust_v it_o from_o its_o own_o place_n see_v both_o be_v of_o the_o same_o weight_n namely_o six_o ounce_n in_o this_o case_n the_o body_n immerge_v and_o the_o water_n wherein_o it_o be_v drown_v become_v of_o the_o same_o weight_n specifical_o see_v bulk_n for_o bulk_n be_v of_o the_o same_o weight_n to_o make_v this_o body_n specifical_o or_o natural_o heavy_a than_o water_n and_o consequent_o to_o sink_v to_o the_o bottom_n nothing_o be_v require_v but_o to_o suppose_v that_o it_o acquire_v one_o ounce_n more_o of_o weight_n which_o do_v it_o present_o go_v down_o i_o be_v more_o burden_v then_o k._n note_v by_o the_o way_n a_o twofold_a weight_n in_o heavy_a body_n one_o individual_a the_o other_o specific_a and_o that_o two_o body_n agree_v in_o individual_a weight_n may_v differ_v in_o specific_a weight_n so_o a_o pound_n of_o lead_n and_o a_o pound_n of_o cork_n agree_v individual_o because_o they_o be_v both_o 16._o ounce_n but_o they_o differ_v specifical_o because_o the_o one_o be_v natural_o heavy_a than_o the_o other_o theorem_fw-la xv._n no_o body_n that_o flot_v above_o water_n even_o though_o its_o upper_a surface_n be_v level_a with_o the_o surface_n of_o the_o water_n can_v ever_o be_v make_v to_o swim_v between_o the_o top_n and_o the_o bottom_n figure_n 1._o for_o clear_v this_o proposition_n let_v we_o suppose_v f_o to_o be_v a_o foursquare_a piece_n of_o timber_n of_o the_o same_o specific_a and_o natural_a weight_n with_o water_n and_o consequent_o its_o upper_a surface_n to_o be_v level_a with_o the_o surface_n of_o the_o water_n a_o b_o c_o d._n i_o say_v then_o if_o it_o be_v press_v down_o to_o r_o it_o shall_v arise_v thence_o and_o never_o rest_n till_o it_o be_v where_o it_o be_v namely_o in_o f._n the_o reason_n seem_v to_o be_v this_o because_o the_o foursquared_a body_n of_o water_n r_o be_v real_o heavy_a than_o the_o foursquared_a piece_n of_o timber_n f._n if_o this_o be_v true_a it_o follow_v of_o necessity_n that_o it_o must_v ascend_v for_o if_o the_o timber_n exist_v in_o r_o be_v light_a than_o the_o water_n r_o the_o water_n t_o must_v be_v less_o press_v than_o the_o water_n o_o or_o the_o water_n v_o whence_o according_a to_o the_o twelve_o theorem_n motion_n must_v follow_v again_o if_o the_o timber_n r_o exist_v in_o the_o water_n r_o be_v light_a than_o the_o same_o water_n be_v then_o must_v the_o water_n k_o be_v more_o press_v up_o then_o the_o water_n i_o or_o l_o whence_o yet_o according_a to_o the_o same_o theorem_fw-la motion_n must_v follow_v if_o it_o be_v say_v that_o the_o timber_n f_o be_v of_o the_o same_o weight_n with_o the_o water_n r_o because_o it_o be_v equal_a in_o weight_n with_o the_o water_n f_o which_o it_o have_v thrust_v out_o of_o its_o own_o place_n it_o must_v also_o be_v equal_a in_o weight_n to_o the_o water_n r_o see_v f_o and_o r_o be_v of_o the_o same_o dimension_n be_v of_o the_o same_o weight_n there_o be_v no_o way_n to_o answer_v this_o difficulty_n unless_o i_o say_v the_o foursquared_a body_n of_o water_n r_o be_v real_o and_o true_o heavy_a than_o the_o foursquared_a body_n of_o water_n f._n the_o reason_n seem_v to_o be_v because_o the_o water_n r_o be_v under_o a_o great_a pressure_n than_o the_o water_n f_o and_o by_o virtue_n of_o this_o great_a pressure_n there_o be_v real_o more_o part_n of_o water_n in_o it_o then_o in_o f_o therefore_o it_o must_v be_v heavy_a even_o as_o there_o be_v far_o more_o part_n of_o air_n in_o one_o cubick_a foot_n near_o the_o earth_n then_o in_o six_o or_o seven_o near_o the_o atmosphere_n hence_o it_o be_v that_o a_o pint_n of_o water_n take_v from_o the_o bottom_n of_o the_o sea_n forty_o fathom_n deep_a will_v be_v heavy_a i_o mean_v in_o a_o balance_n than_o a_o pint_n take_v from_o the_o surface_n take_v notice_n that_o when_o the_o vessel_n be_v once_o full_a at_o the_o bottom_n the_o orifice_n must_v be_v close_o stop_v till_o it_o come_v to_o the_o top_n otherwise_o the_o part_n that_o be_v compress_v at_o the_o bottom_n namely_o by_o the_o weight_n of_o the_o superior_a part_n relax_n themselves_o before_o they_o come_v to_o the_o top_n theorem_fw-la xvi_o it_o be_v not_o impossible_a for_o a_o body_n to_o be_v suspend_v between_o the_o surface_n and_o the_o bottom_n figure_n 1._o for_o understand_v this_o suppose_v f_o to_o be_v a_o foursquare_a piece_n of_o timber_n which_o though_o it_o will_v not_o rest_v but_o at_o the_o surface_n a_o b_o c_o d_o yet_o may_v be_v make_v to_o go_v down_o of_o its_o own_o accord_n and_o rest_n at_o t_o namely_o by_o make_v it_o so_o much_o heavy_a as_o the_o water_n t_n be_v heavy_a than_o the_o water_n f._n to_o know_v this_o difference_n which_o be_v not_o very_o practicable_a the_o cube_n of_o water_n t_o must_v be_v bring_v from_o its_o own_o place_n under_o the_o same_o degree_n of_o pressure_n it_o have_v and_o put_v into_o the_o scale_n of_o a_o balance_n and_o weigh_v with_o the_o cube_n of_o water_n f_o put_v into_o the_o other_o scale_n now_o if_o the_o water_n t_o be_v half_o a_o ounce_n heavy_a than_o the_o water_n f_o then_o to_o make_v the_o timber_n f_o hang_v in_o t_o it_o must_v be_v make_v half_o a_o ounce_n heavy_a there_o seem_v to_o be_v reason_n for_o it_o
also_o for_o if_o a_o cube_n of_o timber_n rest_v in_o the_o space_n t_o be_v just_o the_o weight_n of_o the_o water_n t_o the_o imaginary_a surface_n o_o t_o v_o be_v no_o more_o press_v then_o if_o t_n be_v water_n and_o so_o it_o can_v go_v downward_o neither_o can_v it_o go_v upward_o see_v the_o under_o part_n of_o the_o water_n r_o be_v no_o more_o press_v up_o by_o the_o timber_n t_o then_o if_o the_o space_n t_n be_v fill_v with_o water_n if_o it_o be_v say_v according_a to_o this_o reason_n a_o stone_n may_v be_v suspend_v in_o a_o deep_a water_n between_o the_o top_n and_o the_o bottom_n which_o be_v absurd_a i_o answer_v such_o a_o thing_n may_v happen_v in_o a_o very_a deep_a water_n for_o put_v the_o case_n a_o cube_n of_o lead_n twelve_o inch_n every_o way_n be_v to_o go_v down_o twelve_o thousand_o fathom_n it_o be_v probable_a it_o will_v be_v suspend_v before_o it_o come_v to_o the_o ground_n for_o come_v to_o a_o imaginary_a surface_n far_o down_o where_o the_o pressure_n be_v great_a a_o cube_n of_o water_n twelve_o inch_n thick_a there_o may_v be_v as_o heavy_a even_o specifical_o as_o the_o cube_n of_o lead_n be_v though_o the_o lead_v be_v ten_o time_n heavy_a specifical_o than_o any_o foot_n of_o water_n at_o the_o top_n if_o water_n suffer_v compression_n of_o part_n by_o the_o superior_a burden_n it_o be_v more_o than_o probable_a that_o the_o second_o foot_n of_o water_n burden_v with_o the_o first_o have_v more_o part_n in_o it_o then_o be_v in_o the_o first_o and_o the_o three_o more_o then_o in_o the_o second_o and_o so_o forth_o and_o consequent_o that_o the_o second_o be_v heavy_a than_o the_o first_o and_o the_o third_z heavy_a than_o the_o second_o now_o if_o this_o be_v why_o may_v not_o that_o foot_n of_o water_n that_o have_v sixty_o thousand_o foot_n above_o it_o by_o virtue_n of_o this_o burden_n be_v so_o compress_v that_o in_o it_o may_v be_v as_o many_o part_n as_o may_v counterbalance_n a_o cube_n of_o lead_n twelve_o inch_n every_o way_n if_o then_o that_o imaginary_a surface_n that_o be_v sixty_o thousand_o foot_n deep_a be_v able_a to_o sustain_v the_o say_a foot_n of_o water_n which_o perhaps_o weigh_v twenty_o pound_n why_o may_v it_o not_o likewise_o sustain_v the_o lead_n that_o be_v both_o of_o the_o same_o dimension_n with_o it_o and_o weight_n hence_o it_o be_v that_o the_o cloud_n do_v swim_v in_o the_o air_n by_o virtue_n of_o a_o counterbalance_n and_o we_o see_v which_o confirm_v this_o doctrine_n that_o the_o thin_a and_o light_a be_v always_o far_a up_o and_o the_o thick_a and_o black_a be_v always_o far_a down_n theorem_fw-la xvii_o the_o low_a the_o part_n of_o a_o fluid_a be_v they_o be_v the_o heavy_a though_o all_o of_o they_o be_v of_o equal_a quantity_n and_o dimension_n figure_n 1._o this_o follow_v from_o the_o former_a which_o may_v appear_v a_o paradox_n yet_o it_o seem_v to_o be_v true_a for_o though_o the_o water_n q_o at_o the_o bottom_n be_v of_o the_o same_o dimension_n with_o the_o water_n e_o at_o the_o top_n yet_o it_o be_v real_o heavy_a which_o happen_v as_o i_o say_v from_o the_o superior_a pressure_n it_o be_v clear_a also_o from_o this_o namely_o the_o cube_n of_o timber_n e_o which_o swim_v upon_o the_o surface_n be_v thrust_v down_o to_o q_o come_v up_o to_o the_o top_n again_o which_o can_v not_o be_v unless_o the_o water_n qui_fw-fr be_v heavy_a than_o the_o water_n e._n i_o suppose_v the_o water_n e_o and_o the_o timber_n e_o to_o be_v exact_o of_o the_o same_o specific_a weight_n and_o consequent_o the_o surface_n of_o the_o timber_n to_o lie_v horizontal_n with_o b_o c_o d._n now_o the_o reason_n why_o the_o timber_n ascend_v from_o q_o to_o e_o be_v no_o other_o than_o this_o namely_o that_o the_o one_o water_n be_v heavy_a than_o the_o other_o for_o the_o under_o part_n of_o the_o water_n p_o be_v more_o press_v up_o with_o the_o timber_n exist_v in_o q_o then_o with_o the_o water_n q_n itself_o it_o must_v yield_v and_o give_v way_n to_o the_o ascent_n for_o if_o the_o cube_n of_o timber_n exist_v in_o q_o be_v as_o heavy_a as_o the_o water_n q_n itself_o it_o will_v no_o more_o press_v upon_o p_o or_o endeavour_v to_o be_v up_o than_o the_o water_n q_n do_v theorem_fw-la xviii_o a_o heavy_a body_n weigh_v less_o in_o water_n then_o in_o air._n figure_n 1._o this_o be_v easy_o prove_v from_o experience_n for_o after_o you_o have_v weigh_v a_o stone_n in_o the_o air_n and_o find_v it_o two_o pound_n and_o a_o half_a take_v it_o and_o suspend_v it_o by_o a_o thread_n knit_v to_o the_o scale_n of_o a_o balance_n and_o let_v it_o down_o into_o the_o water_n and_o you_o shall_v find_v it_o half_o a_o pound_n light_a the_o question_n than_o be_v why_o do_v it_o lose_v half_a a_o pound_n of_o its_o weight_n i_o answer_v the_o stone_n become_v half_o a_o pound_n light_a because_o the_o surface_n of_o water_n on_o which_o it_o rest_v sustain_v half_o a_o pound_n of_o it_o for_o put_v the_o case_n a_o stone_n be_v rest_v in_o r_o that_o weigh_v two_o pound_n and_o a_o half_a in_o the_o air_n it_o behove_v to_o weigh_v but_o two_o pound_n in_o this_o water_n because_o the_o water_n t_n sustain_v half_o a_o pound_n of_o it_o for_o if_o this_o water_n t_o be_v able_a to_o sustain_v the_o water_n r_o that_o weigh_v half_o a_o pound_n it_o must_v be_v also_o able_a to_o sustain_v half_o a_o pound_n of_o the_o stone_n see_v half_o a_o pound_n of_o stone_n be_v no_o heavy_a then_o half_a a_o pound_n of_o water_n note_v that_o when_o a_o heavy_a body_n be_v weigh_v in_o water_n it_o become_v so_o much_o light_a exact_o as_o be_v the_o weight_n of_o the_o water_n it_o thrust_v out_o of_o its_o own_o place_n theorem_fw-la xix_o a_o heavy_a body_n weigh_v less_o nigh_o the_o bottom_n of_o the_o water_n then_o nigh_o the_o top_n thereof_o figure_n 1._o for_o clear_v this_o proposition_n i_o must_v suppose_v from_o the_o 17._o theorem_fw-la that_o the_o low_a the_o part_n of_o water_n be_v they_o be_v the_o heavy_a though_o all_o of_o they_o be_v of_o equal_a dimension_n if_o then_o the_o low_a foot_n q_o be_v heavy_a that_o be_v have_v more_o part_n in_o it_o than_o the_o foot_n n_o it_o of_o necessity_n follow_v that_o a_o stone_n suspend_v in_o q_o must_v be_v light_a than_o while_o it_o be_v suspend_v in_o n_o or_o i._o because_o if_o a_o stone_n be_v light_a in_o water_n then_o in_o air_n as_o be_v say_v even_o by_o as_o much_o as_o be_v the_o weight_n of_o the_o bulk_n of_o water_n that_o the_o bulk_n of_o the_o stone_n expel_v then_o sure_o it_o must_v be_v light_a in_o the_o one_o then_o in_o the_o other_o place_n because_o suspend_v in_o q_o it_o expel_v more_o part_n of_o water_n then_o while_o it_o be_v suspend_v in_o n_o or_o i._o for_o example_n let_v we_o suppose_v the_o water_n n_o to_o weigh_v eight_o ounce_n and_o the_o water_n q_o to_o weigh_v nine_o then_o must_v the_o stone_n suspend_v in_o q_o weigh_v less_o by_o a_o ounce_n then_o suspend_v in_o n_o see_v as_o much_o be_v deduce_v from_o the_o weight_n of_o the_o stone_n as_o be_v the_o weight_n of_o the_o water_n it_o expel_v but_o so_o it_o be_v that_o it_o thrust_v nine_o ounce_n of_o water_n out_o of_o its_o own_o place_n in_o q_o and_o but_o eight_o in_o n_o or_o i_o therefore_o it_o must_v be_v one_o ounce_n light_a in_o the_o one_o place_n then_o in_o the_o other_o this_o may_v be_v try_v with_o a_o nice_a and_o accurate_a balance_n which_o will_v bring_v we_o to_o the_o knowledge_n of_o this_o namely_o how_o much_o the_o foot_n of_o water_n q_n be_v heavy_a than_o the_o water_n n_o or_o o._n theorem_fw-la xx._n one_o part_n of_o a_o fluid_a can_v be_v under_o compression_n unless_o all_o the_o part_n next_o adjacent_a be_v under_o the_o same_o degree_n of_o pressure_n figure_n 1._o this_o proposition_n may_v be_v prove_v by_o many_o instance_n for_o when_o the_o air_n of_o a_o windgun_n be_v reduce_v to_o less_o quantity_n by_o the_o rammer_n all_o the_o part_n be_v most_o exact_o of_o the_o same_o bensil_n so_o be_v it_o in_o a_o bladder_n full_a of_o wind_n it_o be_v true_a not_o only_o in_o order_n to_o this_o artificial_a pressure_n but_o in_o order_n to_o the_o natural_a pressure_n and_o bensil_n of_o the_o air_n likewise_o for_o the_o air_n within_o a_o parlour_n have_v all_o its_o part_n under_o the_o same_o degree_n of_o natural_a compression_n so_o be_v it_o with_o the_o part_n of_o the_o air_n that_o be_v without_o and_o immediate_o under_o the_o weight_n of_o the_o atmosphere_n it_o be_v evident_a also_o in_o
the_o part_n of_o water_n for_o the_o foot_n of_o water_n r_o can_v be_v under_o pressure_n unless_o the_o water_n s_o and_o n_o be_v under_o the_o same_o degree_n of_o it_o though_o this_o be_v true_a of_o fluids_n while_o all_o the_o part_n lie_v in_o the_o same_o horizontal_n surface_n yet_o to_o speak_v strict_o it_o will_v not_o hold_v true_a of_o the_o part_n situate_v under_o divers_a surface_n for_o without_o question_n the_o foot_n of_o water_n t_o must_v be_v under_o four_o degree_n of_o pressure_n if_o the_o water_n r_o be_v under_o three_o and_o if_o the_o air_n in_o the_o low_a story_n of_o a_o building_n be_v under_o six_o degree_n of_o bensil_n the_o air_n in_o the_o high_a story_n must_v be_v under_o five_o if_o a_o man_n will_v distinguish_v metaphysical_o and_o subtle_o he_o will_v find_v a_o difference_n of_o this_o kind_n not_o only_o between_o the_o first_o and_o second_o fathom_n of_o air_n near_o to_o the_o earth_n but_o between_o the_o first_o and_o second_o foot_n yea_o between_o the_o first_o and_o second_o inch_n and_o less_o much_o more_o in_o water_n as_o to_o sense_n however_o it_o be_v yet_o the_o theorem_fw-la hold_v true_a for_o we_o find_v no_o difference_n sensible_a between_o the_o compression_n of_o air_n in_o this_o room_n and_o the_o compression_n of_o air_n in_o the_o next_o room_n above_o it_o no_o not_o with_o the_o baroscope_n or_o torricellian_a experiment_n that_o discern_v such_o difference_n accurate_o i_o judge_v it_o likewise_o to_o be_v true_a in_o order_n to_o the_o next_o adjacent_a part_n of_o fluid_n of_o different_a kind_n for_o while_o a_o surface_n of_o mercury_n be_v burden_v with_o a_o pillar_n of_o water_n or_o a_o surface_n of_o water_n with_o a_o pillar_n of_o air_n whatever_o degree_n of_o weight_n and_o pressure_n be_v in_o the_o low_a part_n of_o these_o pillar_n the_o same_o be_v communicate_v entire_o to_o the_o surface_n that_o sustain_v they_o so_o then_o there_o be_v as_o much_o force_n and_o power_n in_o the_o surface_n of_o any_o water_n as_o there_o be_v weight_n and_o pressure_n in_o the_o low_a foot_n of_o any_o pillar_n of_o air_n that_o rest_v upon_o it_o otherwise_o the_o surface_n of_o water_n will_v never_o be_v able_a to_o support_v the_o say_a pillar_n for_o a_o surface_n of_o six_o degree_n of_o force_n can_v never_o be_v able_a to_o sustain_v a_o a_o pillar_n of_o air_n of_o eight_o or_o ten_o degree_n of_o weight_n theorem_fw-la xxi_o the_o pressure_n of_o fluids_n may_v be_v as_o much_o in_o the_o least_o part_n as_o in_o the_o whole_a figure_n 1._o this_o theorem_fw-la may_v seem_v hard_a yet_o it_o can_v be_v make_v manifest_a by_o many_o instance_n for_o albeit_o the_o quantity_n of_o air_n that_o fill_v a_o parlour_n be_v little_a in_o respect_n of_o the_o whole_a element_n yet_o sure_o there_o be_v as_o much_o pressure_n in_o it_o as_o in_o the_o whole_a because_o experience_n show_v that_o the_o mercurial_a cylinder_n in_o the_o baroscope_n will_v be_v as_o well_o sustain_v in_o a_o chamber_n as_o without_o and_o under_o the_o whole_a atmosphere_n direct_o which_o can_v not_o be_v unless_o the_o small_a portion_n of_o air_n that_o be_v in_o this_o parlour_n have_v as_o much_o pressure_n in_o it_o as_o in_o the_o whole_a element_n beside_o this_o it_o will_v be_v find_v in_o a_o far_o less_o quantity_n for_o though_o the_o baroscope_n be_v enclose_v and_o imprison_v so_o close_o within_o a_o small_a vessel_n that_o the_o air_n within_o can_v have_v no_o communion_n with_o the_o air_n without_o yet_o the_o pressure_n of_o that_o very_a small_a quantity_n will_v sustain_v 29._o inch_n of_o mercury_n and_o this_o will_v come_v to_o pass_v even_o though_o the_o whole_a element_n of_o air_n be_v annihilate_v this_o proposition_n be_v likewise_o evident_a in_o order_n to_o the_o pressure_n of_o the_o water_n for_o put_v the_o case_n the_o baroscope_n who_o mercurial_a cylinder_n be_v 29._o inch_n by_o the_o pressure_n of_o the_o air_n be_v send_v down_o to_o the_o bottom_n of_o a_o sea_n 34._o foot_n deep_a within_o a_o vessel_n as_o a_o hogshead_n and_o there_o exact_o enclose_v that_o the_o water_n within_o can_v have_v no_o commerce_n with_o the_o water_n without_o yet_o as_o well_o after_o this_o shut_v up_o as_o before_o other_o 29._o inch_n will_v be_v sustain_v by_o the_o pressure_n of_o this_o imprison_a water_n which_o prove_v evident_o that_o there_o be_v as_o much_o pressure_n in_o one_o hogshead_n full_a of_o water_n at_o the_o bottom_n of_o the_o sea_n as_o in_o the_o whole_a element_n of_o water_n above_o or_o about_o for_o a_o element_n of_o water_n never_o so_o spacious_a if_o it_o exceed_v not_o 34._o foot_n in_o deepness_n can_v sustain_v no_o more_o mercury_n than_o 29._o inch_n by_o its_o pressure_n yea_o though_o the_o vessel_n with_o the_o baroscope_n and_o imprison_a water_n in_o it_o be_v bring_v above_o to_o the_o free_a air_n yet_o will_v the_o water_n retain_v the_o same_o pressure_n and_o 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a_o light_a fluid_n be_v able_a to_o press_v with_o as_o great_a burden_n as_o a_o heavy_a figure_n 2._o this_o proposition_n be_v true_a not_o only_o of_o water_n in_o respect_n of_o mercury_n but_o of_o air_n in_o respect_n of_o they_o both_o for_o albeit_o air_n be_v a_o thousand_o time_n light_a than_o water_n yet_o may_v it_o have_v as_o great_a a_o pressure_n with_o it_o as_o water_n as_o be_v evident_a from_o this_o second_o schematism_n where_o by_o the_o pressure_n of_o the_o outward_a air_n g_o h_o a_o b_o twenty_o nine_o inch_n of_o mercury_n o_o p_o be_v support_v as_o well_o as_o the_o twenty_o nine_o inch_n e_o o_fw-fr by_o the_o pressure_n of_o the_o water_n a_o b_o e_o f._n so_o do_v the_o same_o air_n sustain_v the_o thirty_o four_o foot_n of_o water_n n_o r_o which_o be_v real_o as_o heavy_a as_o the_o twenty_o nine_o inch_n of_o mercury_n o_o p._n now_o if_o the_o weight_n of_o the_o atmosphere_n be_v equivalent_a to_o the_o weight_n of_o thirty_o four_o foot_n of_o 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l_o be_v put_v into_o the_o scale_n of_o a_o balance_n it_o will_v exact_o counterpoise_v the_o thirty_o four_o foot_n of_o water_n n_o r_o pour_v into_o the_o other_o scale_n item_n that_o as_o much_o water_n as_o will_v fill_v the_o tub_n between_o e_z and_o a_o be_v just_a the_o weight_n of_o the_o mercury_n e_o o._n last_o that_o as_o much_o air_n as_o will_v fill_v the_o pipe_n between_o o_o and_o g_o be_v just_a the_o weight_n of_o the_o mercury_n o_o p._n theorem_fw-la xxviii_o the_o pressure_n of_o fluids_n do_v not_o diminish_v while_o you_o subtract_v from_o their_o thickness_n but_o only_o when_o you_o subtract_v from_o their_o altitude_n figure_n 1._o for_o understand_v this_o let_v we_o look_v upon_o the_o first_o schematism_n where_o there_o be_v four_o pillar_n of_o water_n now_o i_o say_v though_o you_o cut_v off_o the_o three_o colume_n of_o water_n upon_o the_o right_a side_n yet_o there_o shall_v remain_v as_o much_o pressure_n in_o the_o quadrat_fw-la foot_n of_o 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the_o water_n a_o b_o be_v not_o able_a to_o press_v up_o the_o water_n h_n i_o or_o the_o slender_a pillar_n of_o air_n i_o g_o within_o the_o pipe_n the_o one_o high_a than_o i_o the_o other_o high_a than_o g._n if_o it_o be_v say_v they_o be_v heavy_a because_o they_o be_v thick_a i_o answer_v they_o be_v true_o heavy_a for_o the_o pillar_n of_o air_n f_o b_o apart_z will_v be_v thrice_o as_o heavy_a as_o the_o slender_a pillar_n of_o air_n i_o g._n but_o if_o you_o reckon_v the_o pillar_n of_o air_n e_o a_o upon_o the_o left_a hand_n both_o together_o will_v be_v six_o time_n heavy_a than_o the_o air_n i_o g_o yet_o be_v they_o not_o able_a either_o several_o or_o conjunct_o to_o press_v up_o the_o water_n h_n i_o high_o than_o i_o or_o the_o air_n i_o g_o high_o than_o g._n for_o solve_v this_o difficulty_n i_o must_v say_v conform_a to_o the_o four_o theorem_n that_o fluid_a body_n counterpoise_v one_o another_o not_o according_a to_o their_o thickness_n and_o breadth_n but_o according_a to_o their_o altitude_n only_o therefore_o see_v the_o slender_a pillar_n of_o air_n i_o g_o be_v as_o high_a as_o either_o f_o b_o or_o e_z a_o it_o can_v be_v press_v up_o by_o they_o for_o by_o virtue_n of_o this_o equal_a height_n all_o the_o three_o press_v equal_o and_o uniform_o upon_o the_o surface_n of_o water_n a_o b_o and_o therefore_o according_a to_o the_o twelve_o theorem_n there_o can_v be_v no_o motion_n but_o if_o so_o be_v the_o pillar_n f_o b_o be_v high_o than_o the_o pillar_n i_o g_o then_o sure_o will_v the_o water_n h_n i_o be_v press_v up_o for_o in_o such_o a_o case_n there_o be_v a_o unequal_a pressure_n or_o if_o the_o pillar_n i_o g_o be_v high_a than_o the_o pillar_n f_o b_o then_o sure_o will_v the_o water_n i_o h_n be_v press_v down_o there_o be_v again_o a_o unequal_a pressure_n the_o water_n within_o the_o pipe_n be_v more_o burden_v than_o the_o water_n about_o the_o pipe_n in_o a_o word_n there_o be_v no_o more_o difficulty_n here_o then_o if_o the_o pipe_n be_v take_v away_o in_o which_o case_n there_o will_v be_v but_o one_o pillar_n of_o air_n rest_v upon_o the_o surface_n of_o water_n a_o b._n if_o it_o be_v say_v the_o pipe_n be_v thrust_v down_o make_v of_o one_o pillar_n three_o distinct_a one_o and_o consequent_o a_o formal_a counterbalance_n or_o mutual_a sustentation_n be_v it_o so_o yet_o because_o all_o these_o press_n uniform_o there_o can_v be_v no_o motion_n theorem_fw-la xxx_o fluids_n press_v not_o only_o according_a to_o perpendicular_a line_n but_o according_a to_o crooked_a line_n figure_n 4._o for_o prove_v this_o proposition_n let_v we_o suppose_v a_o b_o c_o d_o to_o be_v a_o large_a vessel_n full_a of_o water_n as_o high_a as_o a_o n_o b_o and_o a_o little_a vessel_n lie_v within_o it_o near_o to_o the_o bottom_n close_o above_o at_o m_o but_o with_o a_o open_a orifice_n downward_o as_o g_z and_o have_v other_o two_o passage_n go_v in_o to_o it_o upon_o the_o right_n and_o leave_v side_n as_o e_z o_o and_o f_o p._n now_o i_o say_v the_o pressure_n of_o this_o water_n be_v not_o only_o from_o n_o to_o m_n in_o a_o straight_a line_n downward_o but_o from_o e_o to_o o_o and_o from_o f_o to_o p_o by_o crooked_a line_n nay_o put_v the_o case_n this_o vessel_n have_v no_o passage_n in_o to_o it_o but_o by_o a_o labyrinth_n or_o entry_n full_a of_o intricate_a wind_n yet_o the_o pressure_n will_v be_v communicate_v through_o all_o these_o even_o to_o the_o middle_n of_o it_o and_o which_o be_v more_o the_o water_n h_n or_o i_o within_o the_o vessel_n will_v be_v under_o the_o same_o
quicksilver_n therefore_o the_o pillar_n of_o air_n that_o counterpoise_v the_o pillar_n of_o quicksilver_n in_o the_o torricellian_a experiment_n be_v 14000_o time_n high_o the_o one_o be_v 29_o inch_n and_o therefore_o the_o other_o be_v 406000_o inch_n which_o will_v amount_v to_o 33833_o foot_n or_o about_o 6766_o fathom_n count_v five_o foot_n to_o a_o fathom_n and_o because_o air_n be_v count_v 1000_o time_n light_a than_o water_n therefore_o the_o pillar_n of_o air_n that_o sustain_v the_o pillar_n of_o water_n be_v 1000_o time_n high_o the_o height_n of_o water_n by_o the_o pressure_n of_o the_o air_n be_v 34_o foot_n and_o therefore_o the_o height_n of_o the_o air_n be_v a_o thousand_o time_n 34_o foot_n and_o because_o water_n be_v reckon_v 14_o time_n light_a than_o mercury_n therefore_o you_o will_v find_v even_o by_o experience_n that_o the_o pillar_n of_o water_n that_o counterpoise_n the_o pillar_n of_o mercury_n be_v 14_o time_n high_o for_o if_o the_o mercury_n be_v ten_o inch_n the_o water_n will_v be_v exact_o 140._o if_o it_o be_v 29_o inch_n the_o water_n will_v be_v thirty_o four_o foot_n the_o reason_n be_v evident_a because_o if_o one_o inch_n of_o mercury_n be_v as_o heavy_a natural_o as_o 14_o inch_n of_o water_n it_o follow_v of_o necessity_n that_o for_o make_v of_o a_o counterpoise_n to_o every_o inch_n of_o mercury_n there_o must_v be_v 14_o of_o water_n and_o these_o in_o altitude_n each_o one_o above_o another_o hydrostatical_a experiment_n for_o demonstrate_v the_o wonderful_a weight_n force_n and_o pressure_n of_o the_o water_n in_o its_o own_o element_n experiment_n i._o figure_n 6._o in_o explicate_v the_o phenomena_n of_o the_o hydrostaticks_n and_o in_o collect_v speculative_a or_o practical_a conclusion_n from_o they_o i_o purpose_v to_o make_v choice_n of_o the_o plain_a and_o most_o easy_a experiment_n especial_o in_o the_o entry_n that_o this_o knowledge_n that_o be_v not_o very_o common_a and_o yet_o very_o useful_a may_v be_v communicate_v to_o the_o mean_a capacity_n for_o if_o at_o the_o first_o any_o mystical_a or_o abstruse_a experiment_n shall_v be_v propose_v with_o intricate_a description_n they_o will_v soon_o discourage_v and_o at_o last_o hinder_v the_o ingenuous_a reader_n from_o make_v progress_n for_o if_o a_o man_n do_v not_o take_v up_o distinct_o the_o experiment_n itself_o first_o he_o shall_v never_o be_v able_a to_o comprehend_v next_o the_o phenomena_n nor_o at_o last_o see_v the_o inference_n of_o the_o conclusion_n next_o though_o some_o of_o the_o trial_n may_v seem_v obvious_a yet_o they_o afford_v excellent_a phenomena_n by_o which_o many_o profound_a secret_n of_o nature_n be_v discover_v and_o if_o that_o be_v it_o be_v no_o matter_n what_o kind_n they_o be_v of_o then_o the_o grand_a design_n here_o be_v not_o to_o multiply_v bare_a and_o naked_a experiment_n for_o that_o be_v a_o work_n to_o no_o purpose_n for_o it_o be_v like_o a_o foundation_n without_o a_o superstructure_n but_o the_o intention_n be_v not_o only_o to_o describe_v such_o and_o such_o thing_n but_o to_o build_v such_o and_o such_o theorem_n upon_o they_o and_o to_o infer_v such_o and_o such_o conclusion_n as_o shall_v make_v a_o stately_a building_n and_o give_v a_o man_n in_o a_o short_a time_n a_o full_a view_n of_o this_o excellent_a doctrine_n for_o the_o first_o experiment_n then_o prepare_v a_o vessel_n of_o any_o quantity_n as_o a_o b_o c_o d_o near_o half_a full_a of_o water_n who_o surface_n be_v m_o h._n prepare_v also_o two_o glass-pipe_n the_o one_o wide_a the_o other_o narrow_a open_a at_o both_o end_n which_o must_v be_v thrust_v down_o below_o the_o water_n first_o stop_v the_o two_o upper_a orifice_n e_z and_o f._n this_o do_v open_v the_o say_v orifice_n and_o you_o shall_v see_v the_o water_n ascend_v in_o the_o wide_a to_o g_z and_o in_o the_o narrow_a to_o h._n now_o the_o question_n be_v what_o be_v the_o reason_n why_o the_o water_n do_v not_o 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within_o the_o pipe_n press_v the_o surface_n l_o k_n with_o as_o great_a a_o burden_n as_o the_o outward_a water_n press_v it_o for_o understand_v this_o you_o must_v know_v that_o when_o the_o orifice_n i_o be_v thrust_v down_o below_o the_o water_n there_o arise_v a_o sort_n of_o debate_n between_o the_o low_a part_n of_o the_o water_n and_o the_o air_n within_o the_o pipe_n the_o water_n strive_v to_o be_v in_o at_o ay_o and_o the_o air_n strive_v to_o keep_v it_o out_o but_o because_o the_o water_n be_v the_o strong_a party_n it_o enter_v the_o orifice_n i_o and_o cause_v the_o air_n retire_v a_o little_a up_o one_o four_o part_n or_o six_o part_n of_o a_o inch_n above_o i_o and_o no_o more_o which_o be_v a_o real_a compression_n it_o suffer_v for_o the_o orifice_n e_o being_z stop_v hinder_v any_o more_o compression_n than_o what_o be_v say_v in_o which_o instant_a of_o time_n the_o debate_n end_v the_o air_n no_o more_o yield_v and_o the_o water_n no_o more_o urge_v by_o which_o mean_v the_o air_n have_v obtain_v a_o degree_n of_o bensil_n more_o than_o ordinary_a by_o the_o pressure_n of_o that_o little_a quantity_n of_o water_n that_o come_v in_o at_o ay_o press_v the_o part_n of_o the_o imaginary_a surface_n it_o rest_v upon_o with_o as_o great_a weight_n as_o the_o outward_a water_n press_v the_o part_n it_o rest_v upon_o but_o when_o the_o orifice_n e_o be_v open_v the_o outward_a water_n m_o l_o and_o h_n k_o press_v the_o imaginary_a surface_n l_o k_n more_o than_o the_o air_n within_o the_o pipe_n can_v do_v and_o the_o reason_n be_v because_o by_o open_v the_o orifice_n above_o the_o internal_a air_n that_o suffer_v a_o degree_n of_o bensil_n more_o than_o ordinary_a present_o be_v free_v and_o consequent_o become_v of_o less_o force_n and_o weight_n which_o the_o water_n find_v that_o have_v a_o little_a enter_v the_o orifice_n i_o instant_o ascend_v to_o g_z it_o be_v less_o press_v than_o the_o water_n without_o the_o pipe_n now_o the_o reason_n why_o it_o ascend_v no_o high_a than_o g_z be_v take_v from_o the_o equal_a pressure_n of_o the_o body_n that_o rest_v upon_o the_o surface_n m_o g_o h_o for_o assoon_o as_o it_o come_v that_o length_n all_o the_o part_n of_o the_o horizontal_a plain_n of_o water_n be_v uniform_o press_v with_o the_o incumb_a air_n both_o within_o the_o pipe_n and_o without_o the_o pipe_n the_o water_n in_o go_v up_o can_v halt_v midway_n between_o i_o and_o g_o for_o then_o there_o shall_v be_v a_o unequal_a pressure_n in_o fluid_n without_o motion_n which_o be_v impossible_a for_o the_o water_n be_v still_o strong_a than_o the_o air_n till_o once_o it_o climb_v up_o to_o g._n from_o this_o experiment_n we_o see_v first_o that_o in_o water_n there_o be_v a_o pressure_n and_o force_n because_o have_v open_v the_o orifice_n e_o which_o be_v only_o causa_fw-la per_fw-la accidens_fw-la of_o this_o motion_n the_o water_n be_v press_v up_o from_o i_o to_o g._n we_o see_v second_o that_o fluid_a body_n can_v never_o cease_v from_o motion_n till_o there_o be_v a_o equal_a pressure_n among_o the_o part_n which_o be_v evident_a from_o the_o ascent_n of_o the_o water_n from_o i_o to_o g_o which_o can_v halt_v in_o any_o part_n between_o ay_o and_o g_o because_o of_o a_o unequal_a pressure_n till_o it_o once_o climb_v up_o to_o g._n we_o see_v three_o that_o fluid_a body_n do_v not_o sustain_v or_o counterpoise_v one_o another_o according_a to_o their_o thickness_n and_o breadth_n but_o only_o according_a to_o their_o altitude_n because_o there_o be_v not_o here_o any_o proportion_n between_o the_o slender_a pillar_n of_o water_n h_n k_o within_o the_o pipe_n and_o the_o outward_a water_n that_o sustain_v it_o i_o mean_v as_o to_o the_o thickness_n therefore_o it_o be_v no_o
m_o g_o h._n the_o same_o phenomenon_n happen_v in_o take_v the_o air_n out_o of_o the_o narrow_a pipe_n f_o k._n the_o reason_n be_v still_o unequal_a pressure_n for_o in_o remove_v the_o air_n that_o be_v within_o the_o pipe_n the_o part_n of_o the_o surface_n m_o and_o the_o part_n h_n remain_v burden_a while_o the_o part_n g_z be_v free_v of_o its_o burden_n therefore_o this_o part_n of_o the_o surface_n be_v liberate_v of_o its_o burden_n that_o come_v down_o through_o the_o pipe_n instant_o rise_v and_o climb_v up_o as_o far_o as_o the_o outward_a air_n rest_v upon_o m_n and_o h_n can_v raise_v it_o which_o be_v to_o e_o 34_o foot_n for_o the_o pressure_n of_o the_o air_n upon_o the_o surface_v of_o all_o water_n according_a to_o the_o 25_o theorem_fw-la be_v equivalent_a to_o the_o weight_n of_o 34_o foot_n of_o water_n must_v raise_v the_o say_a water_n in_o the_o pipe_n 34_o foot_n you_o do_v not_o wonder_v why_o it_o rise_v from_o i_o to_o g_o as_o in_o the_o first_o experiment_n no_o more_o ought_v you_o to_o wonder_n why_o it_o rise_v from_o g_z to_z e_z see_v the_o weight_n of_o the_o air_n do_v the_o same_o thing_n that_o 34_o foot_n of_o water_n rest_v upon_o the_o surface_n m_o h_n will_v do_v from_o this_o experiment_n we_o see_v first_o that_o the_o pressure_n of_o the_o air_n be_v the_o proper_a cause_n of_o the_o motion_n of_o water_n up_o through_o pump_n and_o siphons_n or_o any_o other_o instrument_n that_o be_v use_v in_o water-work_n of_o that_o kind_n for_o if_o the_o weight_n of_o the_o air_n rest_v upon_o the_o surface_n m_o h_n be_v the_o cause_n why_o the_o water_n climb_v up_o from_o g_z to_z e_z the_o same_o must_v be_v the_o cause_n why_o the_o stagnant_a water_n follow_v the_o sucker_n of_o the_o pump_n while_o it_o be_v pull_v up_o and_o the_o same_o be_v the_o cause_n why_o water_n ascend_v the_o leg_n of_o a_o siphon_n and_o be_v the_o cause_n why_o motion_n continue_v after_o suction_n be_v end_v we_o see_v second_o that_o every_o press_v fluid_a have_v a_o sphere_n of_o activity_n to_o which_o it_o be_v able_a to_o raise_v the_o fluid_a that_o be_v press_v this_o be_v evident_a in_o this_o experiment_n because_o the_o pressure_n of_o the_o air_n rest_v upon_o m_n h_n be_v able_a to_o raise_v the_o water_n the_o height_n of_o e_o in_o the_o wide_a pipe_n and_o the_o height_n of_o f_o in_o the_o narrow_a and_o no_o further_o even_o though_o the_o say_v pipe_n be_v far_o long_o and_o this_o altitude_n and_o high_a point_n be_v precise_o 34_o foot_n between_o air_n and_o water_n we_o see_v three_o that_o it_o be_v all_o one_o matter_n whether_o pump_n and_o siphons_n be_v wide_a or_o narrow_a whether_o the_o tub_n of_o the_o baroscope_n be_v wherein_o the_o mercury_n be_v suspend_v of_o a_o large_a diameter_n or_o of_o a_o lesser_a diameter_n this_o be_v also_o evident_a from_o the_o same_o experiment_n see_v there_o be_v no_o more_o difficulty_n in_o cause_v the_o water_n ascend_v the_o wide_a pipe_n than_o in_o cause_v it_o ascend_v the_o narrow_a one_o and_o the_o reason_n be_v because_o the_o press_a fluid_n repect_v not_o the_o press_v fluid_a according_a to_o its_o thickness_n and_o breadth_n but_o only_o according_a to_o its_o altitude_n therefore_o '_o be_v as_o easy_a for_o the_o air_n to_o press_v up_o water_n through_o a_o pump_n four_o foot_n in_o diameter_n as_o to_o press_v it_o up_o through_o a_o pump_n but_o one_o foot_n in_o diameter_n experiment_n iv._o figure_n 7._o this_o schematism_n represent_v a_o large_a vessel_n full_a of_o water_n who_o first_o and_o visible_a surface_n be_v d_o e_o h_o k._n the_o second_o that_o be_v imaginary_a be_v l_o i_o six_o foot_n below_o it_o the_o three_o of_o the_o same_o kind_n be_v m_n g_o six_o foot_n low_o the_o four_o be_v n_o f_o o_o six_o foot_n yet_o low_o the_o last_o and_o low_a be_v a_o b_o c._n there_o be_v here_o also_o four_o tub_n or_o rather_o one_o tub_n under_o four_o divers_a position_n with_o both_o end_n open_a after_o this_o tub_n d_o a_o be_v thrust_v below_o the_o water_n till_o it_o ascend_v as_o high_a as_o d_o in_o it_o lift_v it_o up_o between_o your_o finger_n till_o it_o have_v the_o position_n of_o the_o second_o pipe_n e_o f_o and_o then_o you_o shall_v see_v as_o the_o orifice_n of_o the_o pipe_n ascend_v the_o cylinder_n of_o water_n fall_v out_o by_o little_a and_o little_a until_o it_o be_v no_o long_o than_o e_o f._n again_o lift_v it_o further_o up_o till_o it_o have_v the_o position_n of_o the_o pipe_n h_o g_o then_o shall_v you_o find_v the_o cylinder_n of_o water_n become_v yet_o short_a last_o if_o it_o be_v situate_v as_o the_o pipe_n k_o i_o the_o internal_a water_n become_v no_o long_a than_o k_o i._o the_o reason_n of_o these_o phenomena_n be_v the_o same_o namely_o unequal_a pressure_n for_o the_o orifice_n a_o be_v lift_v up_o as_o high_a as_o f_o it_o come_v to_o the_o imaginary_a surface_n n_o o_o which_o be_v not_o under_o so_o much_o pressure_n as_o the_o other_o be_v therefore_o one_o part_n of_o it_o be_v more_o burden_v than_o another_o namely_o the_o part_n upon_o which_o the_o cylinder_n of_o water_n rest_v it_o present_o yield_v and_o suffer_v the_o cylinder_n to_o become_v short_a and_o light_a till_o it_o become_v no_o heavy_a than_o be_v proportionable_a to_o its_o own_o strength_n to_o make_v this_o reason_n more_o evident_a it_o be_v to_o be_v note_v that_o no_o surface_n of_o water_n be_v able_a to_o support_v a_o cylinder_n high_a than_o its_o own_o deepness_n that_o be_v to_o say_v if_o a_o surface_n be_v 40_o foot_n deep_a it_o be_v able_a to_o sustain_v a_o cylinder_n 40_o foot_n high_a and_o no_o more_o therefore_o the_o surface_n n_o o_o be_v but_o 18_o foot_n deep_a it_o can_v sustain_v a_o cylinder_n 24_o foot_n long_o for_o if_o that_o be_v than_o the_o potentia_n shall_v be_v inferior_a to_o the_o pondus_fw-la which_o be_v impossible_a in_o the_o hydrostaticks_n in_o effect_n it_o be_v no_o less_o absurdity_n then_o to_o say_v 18_o ounce_n be_v able_a to_o counterbalance_v 24._o for_o a_o second_o trial_n lift_v up_o the_o same_o pipe_n high_o till_o it_o acquire_v the_o position_n of_o the_o tub_n g_o h_n in_o this_o case_n the_o cylinder_n of_o water_n within_o it_o become_v yet_o short_a even_o no_o long_o than_z g_z h._n the_o reason_n be_v the_o same_o namely_o unequal_a pressure_n for_o when_o a_o cylinder_n of_o water_n 18_o foot_n high_a come_v to_o rest_v upon_o this_o surface_n that_o be_v but_o 12_o foot_n deep_a it_o make_v one_o part_n of_o it_o more_o burden_v than_o another_o therefore_o the_o part_n that_o be_v more_o press_v present_o yield_v and_o suffer_v the_o cylinder_n to_o fall_v down_o till_o the_o pondus_fw-la of_o it_o become_v equal_a to_o its_o own_o potentia_fw-la for_o the_o last_o trial_n lift_v up_o the_o tub_n till_o it_o acquire_v the_o position_n of_o the_o pipe_n k_o i_o in_o this_o case_n the_o water_n within_o it_o become_v no_o long_o than_o k_o i_o the_o surface_n l_o i_o that_o be_v but_o six_o foot_n deep_a not_o be_v able_a to_o sustain_v a_o cylinder_n 12_o foot_n high_a from_o this_o experiment_n we_o see_v first_o that_o in_o all_o fluid_a body_n there_o be_v a_o pressure_n which_o be_v more_o or_o less_o according_a to_o the_o deepness_n of_o that_o fluid_a this_o be_v evident_a from_o the_o four_o several_a surface_n there_o be_v more_o pressure_n and_o force_n in_o the_o low_a a_o b_o c_o then_z in_o the_o next_z n_o o_o and_o more_o in_o this_o then_o in_o the_o surface_n m_o g_o and_o more_o in_o this_o then_o in_o l_o 1_n we_o see_v second_o that_o in_o all_o fluid_n there_o be_v a_o pondus_fw-la and_o a_o potentia_n which_o two_o be_v always_o of_o equal_a force_n and_o strength_n the_o potentia_n be_v clear_a and_o evident_a in_o the_o surface_n by_o support_v the_o pillar_n which_o pillar_n be_v nothing_o else_o but_o the_o pondus_fw-la support_v and_o that_o they_o be_v always_o of_o equal_a strength_n be_v most_o evident_a also_o for_o when_o you_o endeavour_v to_o make_v the_o pondus_fw-la unequal_a to_o the_o potentia_n in_o make_v a_o surface_n 18_o foot_n deep_a to_o support_v a_o pillar_n 24_o foot_n high_a they_o of_o their_o own_o accord_n become_v equal_a the_o pillar_n become_v short_a and_o suitable_a to_o the_o strength_n of_o the_o surface_n that_o sustain_v it_o we_o see_v three_o that_o it_o be_v impossible_a for_o one_o part_n of_o the_o same_o horizontal_n surface_n to_o be_v more_o burden_v than_o another_o for_o when_o you_o endeavour_v to_o do_v it_o by_o set_v a_o long_a pillar_n upon_o it_o the_o part_n burden_v
80_o in_o the_o four_o and_o so_o forth_o until_o it_o become_v 1000_o he_o will_v find_v the_o great_a difficulty_n the_o long_o he_o pull_v it_o be_v just_a so_o with_o air_n or_o water_n raise_v mercury_n in_o a_o tub_n for_o as_o the_o cylinder_n of_o the_o mercury_n grow_v high_a by_o rise_v so_o it_o become_v heavy_a and_o consequent_o the_o imaginary_a surface_n upon_o which_o the_o base_a of_o the_o pillar_n rest_v be_v more_o and_o more_o burden_a and_o so_o become_v less_o and_o less_o able_a to_o press_v it_o up_o this_o lead_v we_o to_o a_o clear_a discovery_n of_o the_o reason_n why_o it_o be_v more_o difficult_a by_o suction_n to_o pull_v up_o mercury_n in_o a_o pipe_n than_o to_o pull_v up_o water_n and_o more_o hard_a to_o suck_v up_o ten_o foot_n of_o water_n then_o to_o suck_v up_o five_o for_o trial_n of_o this_o which_o be_v soon_o do_v take_v a_o slender_a glass-pipe_n 30_o or_o 40_o inch_n long_o open_a at_o both_o end_n and_o drown_v the_o one_o end_n among_o quicksilver_n and_o put_v your_o mouth_n to_o the_o other_o and_o have_v suck_v you_o will_v find_v great_a difficulty_n to_o pull_v up_o through_o the_o pipe_n 15_o inch_n of_o mercury_n than_o to_o pull_v up_o 10_o or_o 8_o and_o far_o great_a difficulty_n to_o suck_v up_o 20_o than_o to_o pull_v up_o 15._o it_o may_v be_v object_v that_o if_o a_o man_n have_v strength_n sufficient_a in_o his_o lung_n to_o suck_v out_o the_o whole_a air_n of_o the_o pipe_n thirty_o inch_n of_o mercury_n will_v come_v as_o easy_o up_o as_o three_z which_o seem_v to_o prove_v that_o the_o difficulty_n of_o the_o mercurie_n up-coming_a depend_v not_o upon_o the_o weakness_n of_o the_o air_n but_o upon_o the_o weakness_n of_o the_o lung_n and_o want_v of_o strength_n to_o suck_v i_o answer_v though_o a_o man_n be_v able_a to_o suck_v out_o the_o whole_a air_n of_o the_o pipe_n yet_o 30_o inch_n will_v never_o ascend_v so_o easy_o as_o ten_o nor_o ten_o so_o easy_o as_o three_o and_o that_o for_o the_o reason_n already_o give_v but_o why_o be_v it_o then_o say_v you_o that_o the_o strong_a the_o suction_n be_v the_o high_a the_o mercury_n ascend_v in_o the_o pipe_n i_o answer_v the_o suction_n serve_v for_o no_o use_n but_o to_o remove_v the_o impediment_n that_o hinder_v the_o mercury_n from_o come_v up_o which_o be_v nothing_o else_o but_o the_o air_n within_o the_o pipe_n now_o the_o more_o of_o this_o air_n that_o be_v take_v away_o by_o suction_n the_o strong_a the_o suction_n be_v the_o more_o air_n be_v take_v away_o the_o â—arder_n up_o come_v the_o mercury_n but_o why_o ought_v there_o to_o be_v difficulty_n in_o the_o suction_n of_o mercury_n to_o the_o altitude_n of_o 15_o or_o 20_o inch_n more_o than_o in_o the_o suction_n of_o water_n to_o that_o altitude_n i_o answer_v when_o i_o suck_v water_n up_o through_o a_o pipe_n the_o suction_n of_o the_o air_n above_o it_o be_v easy_a because_o the_o ascend_a water_n help_v much_o to_o drive_v it_o up_o to_o the_o mouth_n the_o outward_a air_n drive_v up_o both_o but_o the_o suction_n be_v difficult_a in_o mercury_n because_o the_o ascend_a liquor_n do_v not_o help_v so_o much_o to_o drive_v up_o the_o air_n to_o the_o mouth_n as_o the_o water_n do_v and_o the_o reason_n be_v because_o the_o air_n be_v more_o burden_v with_o 15_o inch_n of_o mercury_n than_o with_o 15_o inch_n of_o water_n can_v so_o easy_o drive_v up_o the_o one_o as_o the_o oâ—her_n and_o so_o mercury_n can_v so_o easy_o drive_v up_o the_o air_n of_o the_o pipe_n to_o the_o mouth_n as_o water_n do_v in_o a_o word_n according_a to_o the_o difference_n of_o specific_a weight_n between_o water_n and_o mercury_n so_o be_v the_o difficulty_n of_o suction_n therefore_o because_o mercury_n be_v 14_o time_n heavy_a than_o water_n there_o be_v 14_o time_n more_o difficulty_n to_o pull_v up_o the_o one_o than_o the_o other_o note_v that_o suction_n be_v not_o take_v here_o strict_o as_o contradistinguish_v from_o pulsion_n but_o in_o a_o large_a sense_n as_o it_o may_v comprehend_v it_o to_o proceed_v a_o little_a further_o let_v we_o suppose_v the_o pillar_n of_o mercury_n see_v the_o 11._o figure_n g_z h_n that_o be_v raise_v by_o the_o surface_n of_o air_n f_o g_o to_o be_v 29_o inch_n and_o every_o inch_n to_o weigh_v one_o ounce_n second_o that_o the_o say_a surface_n have_v 29_o degree_n of_o power_n or_o force_v in_o it_o for_o in_o all_o counterpoise_n the_o pondus_fw-la and_o the_o potentia_n be_v equal_a therefore_o if_o the_o mercury_n be_v 29_o inch_n the_o potentia_fw-la of_o the_o surface_n must_v have_v 29_o degree_n of_o strength_n or_o force_n in_o it_o to_o counterbalance_v the_o pondus_fw-la these_o thing_n be_v suppose_v which_o be_v evident_a let_v we_o imagine_v the_o surface_n of_o air_n to_o raise_v the_o mercury_n one_o inch_n above_o f_o g._n in_o this_o case_n the_o surface_n be_v weak_a than_o it_o be_v which_o i_o prove_v evident_o because_o it_o be_v now_o but_o able_a to_o raise_v 28_o of_o mercury_n imagine_v next_o the_o say_a surface_n to_o have_v raise_v the_o mercury_n two_o inch_n above_o f_o g_o than_o it_o follow_v that_o it_o must_v be_v yet_o weak_a because_o it_o be_v now_o but_o able_a to_o raise_v 27_o inch_n for_o by_o support_v two_o ounce_n of_o the_o pondus_fw-la it_o lose_v two_o degree_n of_o its_o own_o potentia_fw-la in_o raiâ—ing_v three_o inch_n of_o mercury_n it_o be_v three_o degree_n weak_a and_o in_o raise_v four_o it_o be_v four_o degree_n weak_a and_o so_o forth_o therefore_o have_v raise_v 28_o inch_n there_o be_v but_o one_o degree_n of_o force_n remain_v in_o the_o surface_n and_o when_o it_o have_v raise_v the_o whole_a namely_o 29_o it_o be_v no_o more_o able_a and_o can_v no_o more_o press_v for_o confirmation_n put_v the_o case_n that_o the_o surface_n of_o air_n f_o g_o be_v as_o able_a and_o have_v as_o much_o pressure_n in_o it_o after_o it_o have_v raise_v 29_o inch_n of_o mercury_n as_o it_o be_v after_o the_o raise_n of_o 10_o then_o it_o follow_v of_o necessity_n that_o after_o the_o raise_n of_o 20_o it_o shall_v raise_v 19_o more_o which_o be_v impossible_a see_v the_o great_a altitude_n be_v 29._o it_o follow_v of_o necessity_n i_o say_v because_o after_o the_o raise_n of_o 10_o it_o be_v able_a to_o raise_v 19_o more_o therefore_o if_o it_o be_v as_o able_a after_o 20_o as_o after_o 10_o it_o must_v raise_v 19_o after_o 20._o yea_o if_o it_o be_v as_o able_a after_o 20_o as_o 10_o it_o must_v be_v as_o able_a after_o 29_o as_o 10._o if_o this_o be_v than_o it_o may_v raise_v other_o 29_o and_o a_o three_o 29_o and_o so_o in_o infinitum_fw-la therefore_o i_o conclude_v that_o when_o two_o fluid_a body_n be_v in_o equilibrio_n one_o with_o another_o or_o when_o the_o pondus_fw-la be_v equal_a to_o the_o potentia_fw-la none_o of_o they_o do_v actual_o press_v upon_o another_o at_o least_o the_o surface_n have_v lose_v all_o its_o power_n and_o pressure_n which_o be_v also_o evident_a in_o the_o pillar_n for_o understand_v this_o let_v we_o suppose_v a_o c_o b_o figure_n 11._o to_o be_v a_o pipe_n 58_o inch_n long_o and_o full_a of_o mercury_n and_o every_o inch_n of_o it_o to_o weigh_v one_o ounce_n now_o when_o the_o orifice_n d_o be_v open_v there_o be_v here_o as_o great_a a_o inequality_n between_o the_o pondus_fw-la and_o the_o potentia_fw-la of_o the_o surface_n of_o air_n e_o b_o on_o which_o it_o rest_v as_o be_v between_o the_o surface_n f_o g_o and_o the_o pondus_fw-la of_o mercury_n h_n g._n for_o as_o f_o g_o have_v 29_o degree_n of_o power_n to_o raise_v g_o h_n so_o the_o pillar_n a_o b_o have_v 29_o ounce_n of_o weight_n to_o overcome_v the_o surface_n e_o b._n and_o as_o the_o surface_n f_o g_o become_v one_o degree_n weak_a by_o raise_v one_o inch_n of_o the_o mercury_n h_o g_o and_o two_o degree_n weak_a by_o raise_v two_o inch_n and_o so_o forward_o till_o it_o lose_v all_o its_o pressure_n so_o the_o pillar_n by_o fall_v down_o one_o inch_n lose_v one_o ounce_n of_o the_o weight_n by_o fall_v down_o two_o it_o lose_v two_o ounce_n and_o so_o forward_o till_o by_o fall_v down_o from_o a_o to_o c_o it_o lose_v all_o its_o weight_n and_o pressure_n but_o here_o occur_v a_o difficulty_n for_o if_o the_o surface_n f_o g_o have_v lose_v all_o its_o pressure_n by_o raise_v the_o mercury_n from_o g_o to_o h_n and_o if_o the_o pillar_n c_o b_o have_v lose_v all_o its_o pressure_n by_o fall_v down_o from_o a_o to_o c_o it_o follow_v that_o when_o a_o pillar_n of_o a_o fluid_a and_o a_o surface_n of_o a_o fluid_a be_v in_o equal_a term_n or_o bring_v to_o
a_o equipondium_fw-la there_o be_v no_o pressure_n in_o they_o at_o all_o for_o answer_v consider_v first_o that_o in_o all_o counterpoise_n there_o be_v necessary_o two_o thing_n the_o movens_fw-la and_o the_o motum_fw-la the_o thing_n that_o move_v and_o the_o thing_n that_o be_v move_v second_o you_o must_v consider_v the_o motum_fw-la to_o have_v a_o ponduâ—_fw-la or_o weight_n in_o it_o and_o the_o movens_fw-la to_o have_v a_o potentia_fw-la or_o power_n wherewith_o it_o move_v that_o weight_n three_o that_o as_o the_o thing_n that_o move_v have_v a_o power_n or_o force_v in_o itself_o whereby_o it_o move_v so_o the_o thing_n that_o be_v move_v have_v a_o power_n or_o force_v in_o itself_o whereby_o it_o resist_v the_o motion_n four_o that_o sometime_o the_o resistance_n of_o the_o thing_n move_v may_v exceed_v the_o power_n of_o the_o movent_fw-la as_o when_o a_o quarrier_n with_o a_o leaver_n endeavour_n to_o prize_v up_o a_o stone_n too_o heavy_a for_o he_o or_o the_o power_n of_o the_o movent_fw-la may_v exceed_v the_o resistance_n of_o the_o weight_n or_o both_o may_v be_v of_o equal_a power_n consider_v five_o that_o as_o the_o pondus_fw-la of_o the_o thing_n move_v begin_v to_o grow_v more_o and_o more_o so_o the_o power_n of_o the_o movent_fw-la decrease_v proportionable_o not_o absolute_o as_o heat_n be_v extinguish_v in_o water_n by_o the_o cold_a air_n when_o it_o be_v remove_v from_o the_o fire_n but_o respective_o for_o example_n when_o a_o man_n hold_v a_o balance_n in_o his_o hand_n with_o six_o pound_n in_o the_o one_o scale_n and_o but_o one_o pound_n in_o the_o other_o if_o you_o add_v another_o pound_n the_o weight_n grow_v more_o and_o the_o power_n and_o force_v of_o the_o opposite_a scale_n grow_v less_o proportionable_o not_o absolute_o for_o it_o still_o remain_v six_o pound_n but_o respective_o that_o be_v to_o say_v six_o pound_n be_v less_o in_o respect_n of_o four_o than_o in_o respect_n of_o five_o or_o the_o resistance_n of_o six_o pound_n be_v less_o two_o counterpoise_v it_o than_o be_v counterpoise_v by_o one_o when_o a_o three_o be_v add_v the_o weight_n grow_v yet_o more_o and_o consequent_o the_o resistance_n of_o the_o opposite_a scale_n become_v yet_o less_o till_o by_o add_v the_o six_o and_o last_o pound_n you_o augment_v and_o increase_v the_o pondus_fw-la to_o that_o same_o degree_n of_o strength_n that_o the_o resistance_n of_o the_o opposite_a scale_n be_v of_o from_o these_o consideration_n i_o say_v the_o surface_n of_o air_n f_o g_o have_v not_o lose_v all_o its_o pressure_n absolute_o by_o raise_v the_o mercury_n from_o g_o to_o h_n but_o only_o respective_o because_o it_o still_o retain_v 29_o degree_n of_o force_n in_o itself_o i_o say_v respective_o because_o when_o the_o mercury_n be_v raise_v ten_o inch_n the_o power_n of_o the_o air_n which_o be_v of_o 29_o degree_n of_o force_n be_v less_o in_o respect_n of_o ten_o ounce_n then_o in_o respect_n of_o five_o or_o the_o power_n of_o 29_o degree_n of_o force_n be_v less_o be_v counterpoise_v by_o ten_o ounce_n than_o be_v counterpoise_v only_o by_o five_o and_o when_o it_o be_v raise_v 20_o it_o be_v yet_o less_o in_o this_o respect_n than_o in_o respect_n of_o ten_o and_o when_o it_o have_v raise_v the_o mercury_n to_o the_o great_a altitude_n h_n it_o may_v be_v say_v to_o have_v lose_v all_o its_o pressure_n see_v it_o be_v not_o able_a by_o virtue_n of_o a_o counterpoise_n to_o do_v any_o more_o even_o as_o six_o pound_n in_o this_o scale_n may_v be_v say_v to_o have_v lose_v all_o its_o resistance_n and_o weight_n by_o put_v in_o the_o other_o scale_n first_o one_o pound_n next_o two_o pound_n and_o then_o three_o pound_n till_o the_o last_o be_v put_v in_o at_o which_o time_n it_o have_v no_o more_o resistance_n though_o this_o be_v yet_o it_o still_o remain_v six_o pound_n even_o so_o the_o air_n f_o g_z still_o remain_v of_o the_o same_o force_n and_o power_n while_o it_o suspend_v the_o mercury_n g_o h_n that_o it_o be_v of_o before_o likewise_o the_o pillar_n a_o b_o can_v be_v say_v to_o have_v lose_v all_o its_o pressure_n absolute_o by_o fall_v down_o from_o a_o to_o c_o but_o only_o respective_o because_o the_o say_a pillar_n c_o b_o be_v still_o 29_o ounce_n weight_n i_o say_v respective_o because_o in_o fall_v down_o ten_o inch_n or_o in_o lose_v ten_o ounce_n the_o weight_n that_o be_v now_o but_o 48_o be_v less_o in_o respect_n of_o 29_o than_o while_o it_o be_v 58._o it_o be_v yet_o less_o when_o it_o have_v fall_v down_o other_o ten_o because_o be_v now_o but_o 38_o it_o must_v be_v yet_o less_o in_o respect_n of_o 29_o than_o 48._o and_o when_o it_o have_v fall_v down_o to_o c_o 29_o it_o may_v be_v say_v to_o have_v lose_v all_o its_o weight_n because_o it_o can_v do_v no_o more_o have_v respective_o lose_v all_o its_o pressure_n from_o what_o be_v say_v we_o see_v a_o clear_a ground_n to_o distinguish_v in_o fluids_n a_o pondus_fw-la and_o a_o potentia_fw-la second_o that_o the_o potentia_fw-la may_v sometime_o exceed_v the_o pondus_fw-la and_o contrariwise_o the_o pondus_fw-la may_v exceed_v the_o potentia_fw-la three_o that_o inequality_n of_o weight_n between_o the_o pondus_fw-la and_o the_o potentia_fw-la be_v the_o cause_n of_o motion_n of_o fluids_n four_o that_o the_o motion_n never_o cease_v till_o the_o pondus_fw-la and_o the_o potentia_fw-la become_v of_o equal_a force_n this_o conclusion_n be_v not_o so_o universal_a as_o the_o rest_n because_o the_o motion_n may_v sometime_o cease_v before_o this_o be_v for_o example_n when_o the_o air_n be_v pâ—â—â—â—ing_v mercury_n up_o through_o a_o tub_n short_a than_o 29_o inch_n the_o motion_n end_v before_o there_o be_v a_o perfect_a counterpoise_n for_o 20_o or_o 15_o inch_n of_o mercury_n can_v never_o counterbalance_v the_o force_n and_o power_n of_o the_o air._n in_o such_o a_o case_n then_o there_o be_v a_o unequal_a pressure_n the_o air_n press_v the_o mercury_n more_o than_o the_o mercury_n do_v the_o air._n experiment_n viii_o figure_n 12._o take_v the_o vessel_n a_o b_o c_o d_o and_o fill_v it_o with_o water_n as_o high_a as_o h_n i._o take_v next_o a_o cylinder_n of_o stone_n f_o g_o and_o drown_v the_o half_a of_o it_o among_o the_o water_n suspend_v it_o with_o a_o chord_n to_o the_o beam_n n_o o_o with_o a_o ring_n at_o e._n now_o in_o this_o case_n though_o the_o stone_n do_v not_o touch_v the_o bottom_n of_o the_o vessel_n yet_o the_o water_n become_v heavy_a than_o before_o for_o discover_v the_o true_a reason_n of_o this_o i_o suppose_v first_o the_o weight_n of_o the_o water_n before_o the_o stone_n be_v drowâ—ed_v to_o be_v 40_o pound_n i_o suppose_v next_o that_o after_o the_o stone_n be_v drown_v the_o say_a water_n to_o weigh_v 50_o pound_n and_o last_o the_o stone_n to_o weigh_v 60_o pound_n i_o say_v then_o the_o water_n must_v be_v 10_o pound_n heavy_a than_o before_o because_o it_o support_v 10_o pound_n of_o the_o stone_n it_o be_v certain_a the_o beam_n be_v less_o burden_v by_o 10_o pound_n than_o before_o if_o this_o be_v then_o sure_o the_o water_n must_v sustain_v it_o it_o be_v great_a temerity_n and_o rashness_n to_o aver_v that_o neither_o the_o beam_n nor_o the_o water_n sustain_v it_o which_o be_v real_o to_o say_v it_o be_v sustain_v by_o nothing_o it_o can_v be_v say_v without_o ignorance_n that_o 10_o pound_n of_o the_o stone_n be_v evanished_a and_o turn_v into_o a_o chimaera_n if_o it_o be_v say_v how_o can_v such_o a_o fluid_a body_n as_o water_n be_v able_a to_o support_v any_o part_n of_o the_o weight_n of_o the_o stone_n that_o be_v such_o a_o heavy_a body_n i_o answer_v there_o be_v here_o no_o difficulty_n for_o if_o the_o imaginary_a surface_n k_o l_o upon_o which_o the_o 10_o pound_n of_o the_o stone_n rest_v be_v able_a to_o sustain_v 10_o pound_n of_o water_n i_o suppose_v the_o stone_n take_v away_o and_o the_o place_n of_o it_o fill_v with_o water_n then_o sure_o it_o must_v also_o be_v able_a to_o sustain_v 10_o pound_n of_o the_o heavy_a metal_n see_v ten_o pound_n of_o lead_n or_o gold_n or_o stone_n be_v no_o heavy_a than_o 10_o pound_n of_o water_n if_o some_o say_v this_o rather_o seem_v to_o be_v the_o reason_n why_o the_o water_n become_v heavy_a after_o the_o stone_n be_v drown_v because_o it_o possess_v the_o place_n of_o as_o much_o water_n as_o will_v weigh_v 10_o pound_n not_o as_o be_v say_v because_o the_o water_n support_v 10_o pound_n of_o it_o therefore_o it_o may_v be_v judge_v and_o thought_n that_o if_o the_o space_n that_o the_o stone_n occupy_v be_v fill_v with_o air_n or_o some_o light_a body_n without_o sensible_a weight_n the_o water_n will_v become_v heavy_a than_o before_o
place_n this_o be_v evident_a because_o the_o stone_n be_v 10_o pound_n light_a in_o water_n than_o in_o the_o air_n because_o the_o water_n that_o will_v fill_v the_o room_n of_o the_o stone_n be_v just_a of_o that_o weight_n we_o see_v three_o that_o the_o pressure_n of_o water_n and_o the_o natural_a weight_n of_o it_o be_v two_o thing_n real_o distinct_a because_o the_o pressure_n may_v be_v augment_v without_o any_o increment_n of_o the_o natural_a weight_n we_o see_v four_a that_o the_o pressure_n or_o bensil_n of_o a_o fluid_a can_v affect_v the_o scale_n of_o a_o balance_n but_o only_o the_o natural_a weight_n we_o see_v five_o that_o a_o body_n natural_o heavy_a than_o water_n weigh_v in_o water_n because_o the_o stone_n f_o g_o make_v the_o water_n about_o it_o 10_o pound_n heavy_a if_o it_o be_v inquire_v whether_o body_n that_o be_v natural_o light_a will_v weigh_v in_o water_n i_o answer_v if_o they_o be_v of_o any_o sensible_a weight_n they_o weigh_v as_o well_o as_o the_o other_o for_o this_o cause_n i_o except_v air._n for_o though_o they_o be_v never_o so_o light_a in_o respect_n of_o water_n yet_o if_o they_o have_v any_o considerable_a gravity_n with_o they_o they_o will_v make_v the_o water_n heavy_a they_o be_v among_o put_v the_o case_n the_o body_n be_v a_o cube_n of_o timber_n of_o six_o inch_n weigh_v sixteen_o ounce_n and_o that_o a_o cube_n of_o water_n of_o that_o quantity_n weigh_v 112_o ounce_n here_o be_v a_o great_a inequality_n between_o their_o natural_a weight_n yet_o if_o that_o piece_n of_o timber_n be_v make_v to_o exist_v in_o the_o middle_n of_o water_n as_o the_o bladder_n do_v it_o will_v make_v it_o 16_o ounce_n heavy_a the_o reason_n be_v this_o these_o 16_o ounce_n be_v either_o support_v by_o a_o surface_n of_o water_n or_o they_o support_v themselves_o this_o last_o be_v impossible_a if_o the_o water_n support_v they_o then_o must_v they_o make_v the_o say_a water_n 16_o ounce_n heavy_a note_v that_o though_o a_o 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in_o the_o air._n d_o e_z be_v a_o tub_n full_a of_o mercury_n 28_o inch_n long_o with_o a_o pillar_n of_o water_n above_o it_o e_o f_o 12_o foot_n and_o eight_o inch_n g_o h_n a_o tub_n 42_o inch_n long_o with_o a_o pillar_n of_o water_n above_o it_o h_n i_o 11_o foot_n and_o six_o inch_n high_a and_o last_o a_o d_o g_o s_o m_o a_o imaginary_a surface_n 15_o foot_n deep_a this_o experiment_n be_v bring_v hither_o to_o demonstrate_v that_o a_o heavy_a body_n weigh_v as_o much_o in_o water_n as_o in_o air_n which_o be_v pointblank_o to_o the_o common_a receive_v opinion_n and_o destructive_a of_o the_o 18_o theorem_fw-la to_o evince_v this_o i_o must_v suppose_v the_o 14_o inch_n of_o mercury_n in_o the_o tub_n a_o b_o to_o weigh_v 14_o ounce_n and_o the_o 28_o inch_n of_o mercury_n d_o e_o to_o weigh_v 28_o ounce_n the_o 42_o inch_n g_o h_n to_o weigh_v i_o mean_v in_o the_o air_n 42_o ounce_n now_o i_o say_v to_o make_v a_o just_a equipondium_fw-la between_o the_o two_o scale_n k_o and_o l_o the_fw-mi must_v be_v 14_o ounce_n put_v into_o the_o scale_n l._n if_o after_o this_o manner_n you_o weigh_v the_o tub_n and_o mercury_n d_o e_o 28_o ounce_n will_v be_v require_v in_o the_o scale_n l_o and_o 42_o if_o you_o weigh_v the_o tub_n and_o mercury_n g_o h._n for_o prove_v this_o doctrine_n i_o must_v appeal_v to_o experience_n which_o will_v not_o fail_v in_o this_o if_o you_o reply_v and_o say_v upon_o supposition_n the_o tub_n and_o mercury_n g_o h_n be_v a_o solid_a piece_n of_o brass_n or_o iron_n thus_o suspend_v in_o the_o water_n ought_v it_o not_o to_o weigh_v less_o here_o than_o in_o the_o air_n even_o as_o much_o less_o as_o be_v the_o weight_n of_o the_o quantity_n of_o water_n it_o put_v out_o of_o its_o place_n why_o then_o shall_v not_o the_o pipe_n h_o g_o with_o the_o mercury_n in_o it_o do_v the_o same_o see_v there_o be_v no_o apparent_a difference_n between_o they_o as_o to_o this_o but_o to_o leave_v this_o which_o will_v appear_v afterward_o and_o to_o let_v the_o reader_n see_v the_o truth_n of_o the_o 18_o theorem_fw-la i_o affirm_v it_o be_v not_o the_o weight_n of_o the_o 14_o ounce_n of_o mercury_n a_o b_o that_o burden_v the_o scale_n of_o the_o balance_n k_o and_o that_o make_v a_o counterpoise_n with_o the_o 14_o ounce_n of_o stone_n or_o lead_v that_o be_v in_o the_o scale_n l._n what_o then_o be_v it_o you_o say_v i_o answer_v it_o be_v 14_o ounce_n of_o the_o pillar_n of_o water_n b_o c_o that_o do_v
this_o neither_o do_v the_o weight_n of_o the_o 28_o ounce_n of_o mercury_n d_o e_o burden_n the_o balance_n but_o only_o 28_o ounce_n of_o the_o water_n e_o f._n neither_o do_v the_o balance_n support_v the_o weight_n of_o the_o 42_o ounce_n of_o mercury_n g_o h_n but_o it_o be_v only_o burden_v with_o 42_o ounce_n of_o the_o water_n h_o i._n the_o reason_n be_v most_o evident_a because_o according_a to_o the_o principle_n of_o the_o hydrostaticks_n already_o lay_v down_o the_o cylinder_n of_o mercury_n a_o b_o within_z the_o tub_n a_o b_o rest_v immediate_o upon_o the_o imaginary_a surface_n of_o the_o water_n a_o d_o g_o and_o therefore_o can_v burden_v the_o scale_n in_o any_o wise_a the_o same_o be_v true_a of_o the_o other_o two_o cylinder_n of_o mercury_n but_o in_o this_o i_o find_v small_a difficulty_n the_o great_a be_v how_o to_o make_v it_o out_o that_o the_o scale_n k_o support_v 14_o ounce_n of_o the_o water_n b_o c_o and_o 28_o of_o the_o water_n e_o f_o and_o 42_o of_o the_o water_n h_n i._o to_o make_v this_o seem_v probable_a consider_v first_o as_o be_v note_v that_o this_o water_n be_v 15_o foot_n deep_a and_o consequent_o the_o pillar_n of_o water_n b_o c_o 13_o foot_n 10_o inch_n the_o water_n e_o f_o 12_o foot_n eight_o inch_n and_o h_n i_o 11_o foot_n and_o a_o half_a consider_v second_o though_o this_o be_v true_a yet_o we_o must_v count_v the_o pillar_n of_o water_n z_o m_o 49_o foot_n high_a the_o reason_n be_v evident_a because_o the_o pressure_n of_o the_o air_n upon_o the_o surface_n of_o all_o water_n according_a to_o the_o 25_o theorem_fw-la be_v equivalent_a to_o 34_o foot_n of_o water_n this_o then_o be_v add_v to_o 15_o make_v 49_o and_o by_o this_o reckon_n the_o water_n b_o c_o be_v 47_o foot_n ten_o inch_n the_o water_n e_o f_o 46_o foot_n eight_o inch_n and_o last_o the_o water_n h_n i_o 45_o foot_n six_o inch_n three_o for_o easy_a count_a i_o must_v suppose_v the_o whole_a cylinder_n z_o m_o to_n weigh_v 42_o ounce_n every_o 14_o inch_n one_o ounce_n and_o consequent_o the_o water_n b_o c_o to_n weigh_v 41_o ounce_n the_o water_n e_o f_o to_o weigh_v 40_o ounce_n the_o water_n h_n i_o 39_o ounce_n note_v that_o in_o physical_a demonstration_n it_o be_v not_o needful_a to_o use_v mathematical_a strictness_n in_o count_v and_o so_o leave_v out_o fraction_n we_o shall_v only_o use_v round_a number_n consider_v four_a that_o in_o all_o fluid_n as_o have_v be_v frequent_o mark_v there_o be_v a_o pondus_fw-la and_o potentia_fw-la the_o water_n b_o c_o be_v the_o pondus_fw-la and_o the_o mercury_n a_o b_o the_fw-fr potentia_fw-la the_o one_o strive_v to_o press_v down_o the_o tub_n the_o other_o strive_v to_o press_v it_o up_o consider_v five_o that_o by_o how_o much_o the_o more_o a_o body_n suspend_v in_o a_o fluid_fw-la be_v press_v up_o by_o so_o much_o the_o less_o the_o weight_n that_o press_v it_o down_o be_v find_v and_o contrariwise_o by_o how_o much_o the_o less_o it_o be_v press_v up_o by_o so_o much_o the_o more_o the_o pressure_n above_o be_v find_v consider_v sixthly_a the_o less_o that_o a_o surface_n of_o water_n be_v burden_v the_o more_o able_a it_o be_v to_o counterbalance_v the_o opposite_a pressure_n and_o the_o more_o it_o be_v burden_v it_o be_v the_o less_o able_a consider_v seventhly_a that_o the_o mercury_n a_o b_o which_o be_v evident_a in_o all_o fluid_n not_o only_o press_v downward_o and_o burden_n the_o surface_n a_o d_o g_o but_o also_o press_v upward_o and_o therefore_o actual_o endeavour_v to_o thrust_v up_o the_o tub_n and_o so_o it_o be_v that_o the_o tub_n be_v press_v between_o two_o namely_o between_o the_o water_n c_o b_o and_o the_o mercury_n within_o it_o now_o from_o these_o consideration_n i_o say_v the_o scale_n k_o must_v support_v and_o bear_v up_o 14_o ounce_n of_o the_o water_n b_o c_o for_o see_v the_o mercury_n be_v support_v by_o the_o surface_n of_o water_n on_o which_o it_o rest_v it_o can_v by_o any_o mean_n burden_v the_o balance_n with_o its_o weight_n and_o see_v it_o actual_o press_v up_o the_o tub_n according_a to_o the_o seven_o consideration_n it_o must_v so_o much_o the_o more_o counterpoise_n according_a to_o the_o six_o the_o opposite_a pressure_n of_o the_o water_n b_o c_o and_o consequent_o diminish_v the_o weight_n of_o it_o so_o that_o the_o balance_n can_v support_v the_o whole_a but_o a_o part_n for_o according_a to_o what_o degree_n of_o force_n the_o mercury_n press_v up_o the_o tub_n with_o according_a to_o the_o same_o must_v the_o pressure_n upon_o the_o top_n of_o the_o tub_n be_v diminish_v and_o so_o if_o the_o mercury_n press_v up_o the_o tub_n with_o the_o force_n of_o 27_o ounce_n the_o water_n b_o c_o must_v press_v it_o down_o with_o 14_o ounce_n only_o and_o so_o the_o cylinder_n b_o c_o that_o weigh_v real_o 41_o ounce_n must_v press_v the_o top_n of_o this_o tub_n only_o with_o 14_o which_o 14_o ounce_n real_o counterpoise_v the_o 14_o ounce_n of_o stone_n in_o the_o scale_n l._n but_o how_o be_v it_o make_v out_o that_o the_o mercury_n a_o b_o press_v up_o with_o 27_o ounce_n for_o understand_v this_o remember_v that_o the_o water_n be_v 49_o foot_n high_a take_v in_o the_o pressure_n of_o the_o air_n and_o that_o a_o water_n of_o that_o deepness_n be_v able_a to_o support_v 41_o inch_n of_o mercury_n every_o inch_n weigh_v one_o ounce_n for_o if_o 14_o of_o water_n be_v able_a to_o support_v one_o of_o mercury_n 49_o foot_n or_o 567_o inch_n must_v support_v 41._o if_o then_o the_o part_n of_o the_o surface_n a_o be_v able_a to_o weigh_v 41_o it_o must_v have_v of_o upward_a pressure_n 27_o ounce_n see_v its_o counterpoise_a de_fw-la facto_fw-la only_o with_o 14._o take_v notice_n that_o in_o the_o hydrostaticks_n the_o word_n press_v or_o weigh_v as_o real_o and_o true_o signify_v a_o weigh_v up_o as_o a_o weigh_v down_o see_v it_o be_v no_o less_o essential_a to_o fluid_a body_n to_o move_v upward_o than_o downward_o and_o that_o with_o equal_a force_n and_o weight_n according_a to_o this_o reason_n the_o balance_n support_v 28_o ounce_n of_o the_o water_n e_o f_o imagine_v the_o second_o tub_n to_o be_v suspend_v as_o the_o first_o see_v the_o cylinder_n of_o mercury_n d_o e_o press_v up_o the_o tub_n only_o with_o the_o weight_n of_o 12_o ounce_n which_o 28_o ounce_n real_o counterpoise_v the_o 28_o ounce_n of_o stone_n in_o the_o scale_n l._n but_o why_o do_v the_o mercury_n a_o b_o press_v up_o with_o 27_o ounce_n and_o the_o mercury_n d_o e_z with_o 12_o for_o answer_v remember_v according_a to_o the_o six_o consideration_n the_o short_a a_o cylinder_n of_o mercury_n be_v the_o surface_n upon_o which_o it_o rest_v be_v the_o strong_a and_o more_o able_a to_o press_v it_o up_o and_o contrariwise_o the_o long_a it_o be_v the_o surface_n be_v the_o more_o unable_a and_o weak_a therefore_o a_o b_o being_z short_a and_o light_a than_o d_o e_z the_o surface_n of_o water_n must_v press_v it_o up_o with_o great_a force_n so_o that_o if_o the_o say_a surface_n a_o m_n be_v able_a to_o press_v up_o the_o mercury_n a_o b_o with_o 27_o ounce_n it_o must_v press_v up_o the_o mercury_n d_o e_o only_a with_o 12_o ounce_n according_a to_o this_o rule_n if_o the_o mercury_n a_o b_o be_v 15_o inch_n high_a it_o will_v press_v up_o only_o with_o 26_o ounce_n if_o it_o be_v 16_o with_o 25_o if_o 17_o with_o 24_o if_o 18_o with_o 23_o and_o so_o forward_o this_o lead_v we_o to_o a_o clear_a discovery_n of_o all_o the_o secret_n here_o for_o if_o the_o mercury_n a_o b_o thrust_v up_o the_o pipe_n with_o the_o weight_n of_o 27_o ounce_n then_o must_v the_o scale_n k_o be_v ease_v of_o so_o much_o weight_n and_o so_o much_o must_v be_v subtract_v from_o l._n now_o let_v we_o imagine_v the_o pipe_n a_o b_o to_o be_v empty_a both_o of_o air_n water_n and_o mercury_n in_o this_o case_n 41_o ounce_n must_v be_v in_o the_o scale_n l_o to_o counterpoise_v it_o see_v the_o whole_a cylinder_n b_o c_o that_o weigh_v so_o much_o do_v now_o real_o counterpoise_v it_o let_v we_o imagine_v next_o these_o 14_o inch_n of_o mercury_n to_o rise_v and_o fill_v the_o tub_n a_o b_o in_o this_o case_n there_o happen_v a_o great_a alteration_n because_o the_o rise_n of_o they_o be_v real_o equivalent_a to_o the_o subtract_v of_o 27_o ounce_n from_o the_o scale_n l_o and_o the_o reason_n be_v because_o by_o so_o rise_v and_o fill_v the_o tub_n they_o thrust_v up_o the_o say_a tub_n and_o by_o this_o mean_n ease_v the_o scale_n k_o of_o so_o much_o weight_n now_o this_o scale_n be_v ease_v you_o must_v of_o necessity_n
take_v out_o from_o l_o 27_o ounce_n for_o make_v a_o new_a counterpoise_n and_o last_o the_o scale_n k_o must_v support_v the_o whole_a weight_n of_o the_o water_n h_n i_o which_o be_v 39_o ounce_n nothing_o remain_v to_o counterbalance_v this_o downward_o pressure_n and_o consequent_o to_o ease_v the_o balance_n how_o then_o be_v it_o counterpoise_v for_o clear_v this_o you_o must_v remember_v that_o this_o water_n that_o be_v real_o 15_o foot_n deep_a must_v be_v reckon_v as_o i_o say_v 49_o because_o of_o the_o pressure_n of_o the_o air_n upon_o the_o top_n that_o be_v equivalent_a to_o 34._o if_o then_o it_o be_v so_o it_o can_v raise_v mercury_n high_o in_o a_o tub_n than_o 42_o inch_n the_o one_o be_v 14_o time_n heavy_a than_o the_o other_o so_o that_o if_o 14_o inch_n of_o water_n can_v raise_v mercury_n high_o than_o one_o inch_n 49_o foot_n can_v raise_v it_o high_o than_o 42_o inch_n for_o as_o 14_o inch_n be_v to_o one_o inch_n so_o be_v 49_o foot_n to_o three_o foot_n and_o a_o half_a which_o be_v 42_o inch_n now_o i_o say_v the_o whole_a weight_n of_o the_o water_n h_n i_o rest_v upon_o the_o top_n of_o the_o tub_n and_o so_o press_v down_o the_o scale_n k_o to_o which_o you_o must_v imagine_v this_o tub_n knit_v by_o a_o string_n as_o the_o former_a be_v nothing_o remain_v to_o counterpoise_v this_o downward_o pressure_n for_o the_o top_n of_o the_o mercurial_a cylinder_n being_n raise_v as_o high_a within_o the_o pipe_n as_o the_o surface_n of_o water_n d_o g_o s_o be_v able_a to_o raise_v it_o the_o say_a top_n can_v impress_v no_o force_n upon_o the_o tub_n within_o to_o thrust_v it_o up_o and_o so_o to_o ease_v the_o scale_n k._n for_o example_n when_o a_o man_n erect_v upon_o his_o hand_n a_o cylinder_n of_o timber_n or_o any_o such_o like_a thing_n which_o be_v the_o outmost_a he_o can_v support_v he_o will_v not_o be_v able_a to_o impress_v any_o impulse_n upon_o the_o seiling_n of_o a_o room_n above_o his_o head_n but_o if_o so_o be_v in_o stead_n of_o that_o take_v away_o there_o be_v one_o light_a erect_v which_o he_o be_v able_a to_o command_v he_o can_v easy_o thrust_v up_o the_o seiling_n at_o his_o pleasure_n just_o so_o it_o be_v here_o for_o the_o 42_o inch_n of_o mercury_n be_v the_o outmost_a that_o the_o surface_n of_o water_n d_o g_o s_o be_v able_a to_o bear_v it_o can_v impress_v any_o impulse_n therewith_o upon_o the_o top_n of_o the_o tub_n within_o but_o easy_o can_v the_o cylinder_n d_o e_o impress_v a_o impulse_n and_o more_o easy_o the_o cylinder_n a_o b_o see_v they_o be_v light_a and_o so_o more_o powerful_a to_o evidence_n this_o a_o little_a more_o let_v we_o imagine_v two_o thing_n first_o the_o tub_n g_o h_n to_o be_v empty_a as_o if_o vacuity_n be_v in_o it_o in_o this_o case_n the_o top_n of_o the_o tub_n ought_v to_o bear_v the_o whole_a burden_n of_o the_o water_n and_o consequent_o the_o balance_n to_o bear_v it_o also_o because_o there_o be_v not_o a_o potentia_fw-la within_o the_o tub_n to_o counterpoise_v this_o pondus_fw-la next_o let_v we_o imagine_v the_o tub_n to_o be_v only_o full_a of_o water_n according_a to_o this_o supposition_n the_o balance_n can_v be_v in_o the_o least_o part_n burden_v because_o the_o water_n within_o the_o pipe_n press_v it_o up_o with_o as_o much_o force_n as_o the_o water_n i_o h_n press_v it_o down_o and_o if_o any_o thing_n shall_v burden_v the_o balance_n it_o will_v be_v only_o the_o weight_n of_o the_o pipe_n that_o be_v not_o considerable_a from_o what_o be_v demonstrate_v we_o see_v first_o that_o though_o this_o experiment_n will_v seem_v to_o prove_v at_o the_o first_o that_o a_o heavy_a body_n weigh_v as_o much_o in_o the_o water_n as_o it_o do_v in_o the_o air_n because_o the_o whole_a weight_n of_o the_o mercury_n a_o b_o be_v find_v in_o the_o scale_n l_o yet_o it_o be_v not_o so_o because_o the_o 14_o ounce_n of_o stone_n l_o do_v not_o counterpoise_v any_o of_o the_o mercury_n a_o b_o but_o 14_o ounce_n of_o the_o pillar_n of_o water_n b_o c._n second_o there_o be_v here_o a_o clear_a ground_n for_o assert_v a_o pondus_fw-la and_o a_o potentia_fw-la in_o fluids_n because_o this_o tub_n a_o b_o be_v press_v down_o with_o the_o water_n b_o c_o and_o press_v up_o with_o the_o mercury_n within_o it_o three_o there_o be_v here_o a_o clear_a ground_n for_o assert_v the_o pressure_n of_o water_n even_o in_o its_o own_o place_n because_o the_o water_n b_o c_o counterpoise_n by_o its_o weight_n the_o 14_o ounce_n of_o stone_n l._n four_o we_o see_v a_o excellent_a way_n for_o find_v the_o weight_n of_o any_o cylinder_n of_o water_n for_o whatever_o be_v the_o weight_n of_o the_o mercury_n in_o the_o tub_n the_o cylinder_n of_o water_n that_o rest_v upon_o the_o top_n will_v be_v of_o the_o same_o weight_n exact_o this_o be_v evident_a in_o compare_v the_o weight_n of_o the_o mercury_n g_o h_n with_o the_o weight_n of_o the_o water_n h_o i._n five_o that_o whatever_o be_v the_o height_n and_o weight_n of_o a_o pillar_n of_o water_n yet_o the_o balance_n can_v sustain_v no_o more_o of_o it_o than_o the_o just_a weight_n of_o the_o mercury_n this_o be_v also_o evident_a because_o the_o scale_n of_o the_o balance_n support_v no_o more_o of_o the_o weight_n of_o the_o water_n b_o c_o than_o the_o just_a weight_n of_o the_o mercury_n a_o b._n we_o see_v sixthly_a the_o further_a down_o a_o pipe_n with_o mercury_n go_v through_o water_n the_o great_a be_v the_o pressure_n it_o make_v upon_o the_o top_n of_o the_o tub_n within_o for_o put_v the_o case_n this_o be_v 100_o foot_n deep_a the_o mercury_n g_o h_n that_o want_v all_o upward_a pressure_n now_o will_v press_v up_o the_o tub_n with_o 40_o ounce_n the_o mercury_n d_o e_z with_o 55_o and_o the_o mercury_n a_o b_o with_o 70._o we_o see_v seventhly_a the_o short_a a_o cylinder_n of_o mercury_n be_v it_o be_v the_o strong_a in_o press_v and_o long_o it_o be_v it_o be_v the_o weak_a for_o there_o be_v more_o strength_n in_o a_o b_o than_z in_o d_o e._n we_o see_v eighthly_a that_o the_o strength_n decay_v and_o grow_v according_a to_o arithmetical_a progression_n as_o 1_o 2_o 3_o 4_o because_o if_o you_o make_v the_o cylinder_n g_z h_n 41_o that_o be_v now_o 42_o it_o press_v up_o with_o one_o ounce_n make_v it_o 40_o inch_n it_o will_v press_v up_o with_o two_o ounce_n of_o weight_n make_v it_o 39_o it_o press_v up_o with_o three_o and_o contrariwise_o make_v the_o cylinder_n d_o e_o 29_o inch_n that_o be_v now_o but_o 28_o it_o will_v press_v up_o with_o 11_o ounce_n only_o with_o 28_o it_o press_v up_o with_o 12._o make_v it_o 30_o inch_n high_a it_o will_v press_v up_o with_o 10._o if_o it_o be_v 31_o inch_n it_o press_v up_o with_o nine_o and_o so_o forward_o last_o make_v the_o cylinder_n a_o b_o 15_o inch_n that_o be_v now_o but_o 14_o it_o press_v up_o with_o 26_o with_o 14_o it_o press_v up_o with_o 27_o make_v it_o 16_o it_o press_v up_o with_o 25_o make_v it_o 17_o it_o press_v up_o with_o 24._o we_o see_v ninthly_a that_o in_o fluids_n we_o may_v make_v a_o distinction_n between_o a_o sustentation_n and_o a_o equipondium_fw-la it_o be_v evident_a here_o because_o there_o be_v a_o perfect_a equipondium_fw-la between_o the_o 42_o inch_n of_o mercury_n g_o h_n and_o the_o outward_a water_n that_o be_v 49_o foot_n deep_a but_o it_o be_v not_o so_o between_o the_o say_a water_n and_o the_o mercury_n d_o e_o because_o the_o say_a water_n be_v able_a to_o raise_v the_o say_a mercury_n 14_o inch_n high_a therefore_o the_o water_n only_o sustain_v the_o mercury_n d_o e_o but_o counterballance_n the_o mercury_n g_o h._n we_o see_v tenthly_a that_o the_o pondus_fw-la of_o the_o pillar_n of_o water_n b_o c_o be_v counterpoise_v by_o two_o distinct_a power_n real_o the_o one_o be_v the_o 14_o ounce_n of_o stone_n in_o the_o scale_n l_o the_o other_o be_v the_o 14_o inch_n of_o mercury_n a_o b_o that_o as_o real_o thrust_v up_o the_o water_n as_o the_o scale_n k_o pull_v it_o up_o by_o virtue_n of_o the_o opposite_a weight_n eleven_o take_v away_o the_o stone_n l_o and_o you_o will_v find_v the_o pipe_n with_o the_o mercury_n a_o b_o sink_v down_o this_o happen_v not_o because_o the_o surface_n of_o water_n on_o which_o it_o rest_v be_v not_o able_a to_o sustain_v it_o but_o because_o the_o 14_o ounce_n of_o the_o water_n b_o c_o that_o be_v support_v by_o the_o stone_n do_v now_o press_v it_o down_o twelve_o the_o more_o a_o body_n be_v unequal_o press_v by_o a_o fluid_a the_o more_o of_o the_o weight_n of_o that_o fluid_n be_v
sensible_a and_o the_o more_o equal_o a_o body_n be_v press_v the_o less_o sensible_a be_v the_o weight_n of_o that_o fluid_a this_o be_v evident_a because_o there_o be_v a_o great_a weight_n of_o the_o water_n h_n i_o find_v in_o the_o balance_n it_o take_v 42_o ounce_n to_o counterpoise_v it_o than_o of_o the_o water_n e_o f_o which_o be_v counterpoise_v with_o 28_o ounce_n and_o the_o reason_n be_v because_o the_o top_n of_o the_o tub_n h_n support_v the_o whole_a 39_o ounce_n of_o water_n h_n i_o the_o mercury_n within_o the_o tub_n not_o be_v able_a in_o the_o least_o to_o counterpoise_v it_o or_o thrust_v it_o up_o but_o because_o the_o tub_n d_o e_o be_v more_o equal_o press_v the_o water_n e_o f_o press_v down_o with_o 40_o and_o the_o mercury_n d_o e_o press_v up_o with_o 12_o therefore_o less_o weight_n of_o the_o water_n e_o f_o burden_v the_o balance_n only_o 28_o ounce_n hence_o it_o be_v that_o because_o the_o tub_n a_o b_o be_v more_o equal_o press_v than_o either_o d_o e_z or_o g_o h_n there_o be_v less_o of_o the_o weight_n of_o the_o water_n b_o c_o find_v in_o the_o balance_n only_o 14_o ounce_n thirteen_o if_o in_o the_o instant_n of_o time_n while_o the_o tub_n be_v thus_o suspend_v in_o the_o water_n the_o pressure_n of_o the_o air_n above_o be_v take_v away_o and_o annihilate_v then_o first_o the_o 42_o inch_n of_o mercury_n g_o h_n will_v fall_v down_o to_o about_o 13_o inch_n second_o the_o 28_o inch_n of_o mercury_n d_o e_o will_v fall_v down_o to_o as_o many_o and_o last_o the_o 14_o a_o b_o will_v sink_v down_o to_o the_o same_o height_n the_o reason_n be_v because_o the_o pressure_n of_o the_o air_n be_v equivalent_a to_o 34_o foot_n of_o water_n no_o more_o will_v remain_v but_o 15_o foot_n which_o be_v the_o real_a height_n according_a to_o z_o m._n but_o 15_o foot_n of_o water_n can_v sustain_v more_o inch_n of_o mercury_n than_o about_o 13._o and_o consequent_o first_o 14_o ounce_n of_o stone_n in_o the_o balance_n will_v counterpoise_v the_o whole_a water_n b_o c._n the_o reason_n be_v because_o the_o water_n b_o c_o be_v but_o of_o 14_o ounce_n and_o the_o mercury_n a_o b_o be_v but_o 13_o inch_n high_a can_v impress_v no_o impulse_n upon_o the_o top_n of_o the_o tub_n within_o that_o be_v 14_o inch_n high_a second_o 13_o ounce_n of_o stone_n in_o the_o scale_n l_o will_v counterpoise_v the_o whole_a water_n e_o f_o see_v e_z f_o be_v but_o 13_o ounce_n three_o the_o same_o weight_n one_o ounce_n be_v deduce_v will_v counterpoise_v the_o water_n h_n i_o because_o in_o this_o case_n it_o weigh_v but_o 12_o ounce_n to_o proceed_v a_o little_a further_o imagine_v the_o pipe_n g_o h_n to_o be_v suspend_v by_o the_o balance_n as_o the_o pipe_n a_o b_o be_v and_o then_o a_o little_a hole_n open_v in_o the_o top_n h_n to_o suffer_v the_o water_n to_o come_v in_o till_o the_o mercury_n subside_o 14_o inch_n namely_o from_o q_o to_o o_o imagine_v this_o tub_n to_o be_v the_o other_o and_o then_o stop_v it_o the_o reason_n why_o the_o water_n rush_v in_o and_o press_v down_o the_o mercury_n be_v the_o force_n and_o pressure_n of_o it_o for_o the_o say_a water_n find_v the_o cylinder_n in_o equilibrio_n with_o the_o outward_a water_n present_o by_o its_o own_o weight_n cast_v the_o scale_n which_o be_v easy_o do_v see_v the_o surface_n g_o s_o m_o support_n as_o much_o burden_n as_o it_o can_v but_o that_o which_o be_v more_o considerable_a be_v this_o after_o the_o subside_v of_o the_o mercury_n from_o q_o to_o o_o the_o equilibrium_n that_o be_v between_o the_o scale_n of_o the_o balance_n and_o the_o water_n q_o r_o be_v destroy_v for_o whereas_o 42_o ounce_n be_v require_v before_o 29_o will_n now_o do_v it_o for_o understand_v the_o reason_n of_o this_o consider_v that_o between_o q_o and_o o_o be_v 14_o inch_n of_o water_n rush_v in_o which_o be_v equivalent_a to_o one_o inch_n of_o mercury_n next_o according_a to_o former_a reason_n the_o balance_n must_v support_v 29_o ounce_n of_o the_o water_n q_o r_o because_o in_o this_o case_n the_o top_n of_o the_o pipe_n within_o be_v press_v up_o with_o the_o weight_n of_o 13_o ounce_n which_o in_o effect_n diminish_v as_o much_o of_o the_o downward_o pressure_n of_o the_o water_n r_o q_n which_o before_o have_v the_o burden_n of_o 39_o ounce_n but_o why_o be_v the_o tub_n press_v up_o with_o 13_o ounce_n i_o answer_v because_o the_o mercury_n that_o before_o be_v 42_o inch_n be_v now_o but_o 28_o or_o have_v the_o 14_o inch_n of_o water_n q_n o_o above_o it_o it_o be_v 29_o therefore_o be_v short_a the_o surface_n g_o s_o m_o be_v the_o more_o able_a to_o press_v it_o up_o even_o with_o as_o much_o more_o force_n as_o it_o be_v in_o inch_n short_a in_o the_o second_o place_n let_v in_o as_o much_o water_n more_o as_o will_v depress_v the_o mercury_n other_o 14_o inch_n namely_o from_o o_o to_o p._n in_o this_o case_n 16_o ounce_n of_o stone_n will_v make_v a_o equipondium_fw-la because_o the_o 14_o inch_n of_o mercury_n p_o s_o and_o the_o 28_o inch_n of_o water_n p_o o_fw-fr qui_fw-fr be_v a_o far_o light_a burden_n by_o 26_o than_o the_o 42_o inch_n of_o mercury_n the_o surface_n g_o s_o m_o must_v be_v far_o able_a to_o press_v they_o up_o now_o than_o before_o and_o therefore_o must_v diminish_v as_o much_o of_o the_o downward_o pressure_n of_o the_o water_n q_o r_o that_o burden_v the_o balance_n as_o themselves_o want_v of_o weight_n see_v then_o the_o whole_a cylinder_n of_o mercury_n and_o water_n together_o be_v but_o equivalent_a for_o weight_n to_o 16_o inch_n of_o mercury_n the_o top_n of_o the_o tub_n within_o must_v be_v press_v up_o with_o 26_o ounce_n and_o therefore_o they_o by_o their_o upward_a pressure_n must_v diminish_v 26_o ounce_n of_o the_o weight_n of_o the_o water_n r_o q_n that_o weigh_v 39_o last_o let_v in_o so_o much_o water_n as_o will_v depress_v the_o last_o 14_o inch_n p_o saint_n and_o you_o will_v find_v no_o more_o weight_n require_v in_o the_o balance_n to_o make_v a_o equipondium_fw-la than_o counterpoise_v the_o simple_a weight_n of_o the_o tub_n which_o be_v not_o considerable_a the_o reason_n be_v because_o the_o part_n s_o of_o the_o surface_n g_o s_o m_o be_v liberate_v of_o the_o burden_n of_o mercury_n and_o sustain_v only_o the_o water_n within_o the_o tub_n in_o stead_n of_o it_o this_o surface_n press_v up_o the_o water_n within_o the_o tub_n and_o consequent_o the_o top_n of_o it_o with_o as_o great_a force_n and_o weight_n as_o the_o top_n of_o the_o tub_n without_o be_v depress_v with_o the_o outward_a water_n r_o q_n therefore_o 39_o ounce_n depress_v the_o tub_n and_o 39_o ounce_n press_v it_o up_o the_o balance_n must_v be_v free_v of_o the_o whole_a weight_n of_o water_n r_o q._n if_o it_o be_v object_v that_o the_o 42_o inch_n of_o water_n q_o s_o be_v equivalent_a in_o weight_n to_o three_o inch_n of_o mercury_n therefore_o the_o part_n of_o the_o surface_n s_o be_v burden_v with_o this_o can_v press_v up_o with_o as_o great_a force_n as_o the_o water_n r_o qui_fw-fr press_v down_o for_o answer_v consider_v that_o the_o part_n s_o be_v able_a to_o support_v 42_o ounce_n of_o water_n and_o next_o that_o the_o water_n r_o qui_fw-fr weigh_v but_o 39_o then_o i_o say_v see_v the_o 42_o inch_n of_o water_n within_o the_o tub_n weigh_v only_o three_o ounce_n the_o part_n s_o that_o be_v burden_v therewith_o be_v able_a to_o support_v 42_o it_o must_v press_v up_o with_o the_o weight_n of_o 39_o and_o so_o counterbalance_v the_o water_n r_o q._n if_o it_o be_v enquire_v whether_o or_o not_o will_v the_o 14_o inch_n of_o mercury_n a_o b_o fall_v down_o a_o small_a hole_n be_v make_v in_o the_o top_n of_o the_o tub_n at_o b_o i_o answer_v they_o will_v if_o it_o be_v object_v that_o these_o 14_o inch_n of_o mercury_n be_v not_o in_o equilibriâ—_fw-la with_o the_o pressure_n of_o the_o ambient_fw-la water_n as_o the_o mercury_n g_o h_n and_o therefore_o they_o can_v be_v so_o easy_o depress_v by_o the_o water_n that_o come_v in_o at_o the_o say_a hole_n i_o answer_v they_o must_v all_o fall_v down_o and_o as_o easy_o as_o the_o other_o and_o that_o because_o of_o inequality_n of_o weight_n between_o the_o potentia_fw-la of_o the_o surface_n of_o water_n and_o the_o pondus_fw-la it_o be_v certain_a the_o part_n a_o of_o the_o surface_n can_v support_v more_o weight_n of_o any_o kind_n than_o 42_o ounce_n but_o when_o a_o hole_n be_v open_v in_o b_o and_o the_o water_n coâ—es_n in_o it_o be_v then_o burden_v with_o the_o weight_n of_o 14_o ounce_n of_o
mercury_n and_o with_o the_o weight_n of_o 41_o ounce_n of_o water_n so_o much_o the_o water_n b_o c_o weigh_v which_o be_v 55_o ounce_n but_o a_o surface_n that_o have_v only_o the_o potentia_n of_o 42_o can_v never_o support_v a_o pondus_fw-la of_o 55_o no_o not_o of_o 43._o it_o may_v be_v object_v thus_o put_v the_o case_n a_o cylinder_n of_o gold_n or_o brass_n be_v suspend_v in_o this_o water_n as_o the_o pipe_n and_o mercury_n g_o h_n be_v suspend_v by_o the_o balance_n will_v not_o the_o balance_n support_v the_o whole_a weight_n of_o it_o without_o support_v any_o part_n of_o the_o weight_n of_o the_o water_n i_o h_n that_o rest_v upon_o the_o top_n of_o it_o i_o answer_v there_o be_v a_o great_a difference_n between_o the_o two_o because_o a_o cylinder_n of_o gold_n or_o brass_n suffer_v both_o the_o upward_a and_o downward_o pressure_n of_o the_o water_n but_o the_o mercury_n g_o h_n suffer_v only_o the_o upward_a pressure_n be_v free_v of_o the_o downward_o by_o the_o top_n of_o the_o tub._n from_o this_o experiment_n of_o let_v in_o the_o water_n upon_o the_o top_n of_o the_o mercury_n we_o see_v first_o that_o when_o two_o fluid_n be_v in_o equilibrio_n one_o with_o another_o a_o very_a small_a weight_n will_v cast_v and_o turn_v the_o scale_n because_o if_o the_o six_o part_n of_o a_o inch_n of_o water_n come_v in_o at_o q_o it_o present_o alter_v the_o height_n of_o the_o mercury_n from_o 42_o inch_n to_o less_o second_o it_o be_v impossible_a for_o a_o surface_n of_o water_n to_o support_v more_o weight_n than_o its_o own_o proper_a burden_n because_o the_o part_n s_o can_v support_v more_o no_o not_o a_o grain_n than_o 42_o ounce_n we_o see_v three_o that_o it_o be_v as_o impossible_a for_o a_o surface_n of_o water_n to_o support_v less_o than_o its_o own_o burden_n because_o whatever_o loss_n of_o weight_n the_o pillar_n of_o mercury_n s_o qui_fw-fr suffer_v by_o the_o ingress_n of_o the_o water_n q_o o_fw-fr it_o be_v make_v up_o again_o by_o the_o same_o water_n if_o it_o be_v object_v that_o the_o 14_o inch_n of_o water_n q_n o_o be_v not_o so_o heavy_a by_o far_o as_o the_o 14_o inch_n of_o mercury_n that_o fall_v down_o i_o answer_v its_o true_a yet_o the_o part_n s_o be_v as_o much_o burden_v as_o before_o because_o what_o be_v want_v in_o weight_n it_o be_v make_v up_o and_o compense_v by_o pressure_n we_o see_v four_a that_o the_o pressure_n of_o a_o fluid_a be_v a_o thing_n real_o distinct_a from_o the_o natural_a weight_n according_a to_o the_o 22_o theorem_fw-la because_o though_o the_o 14_o inch_n of_o water_n q_n o_o be_v not_o so_o heavy_a natural_o as_o the_o 14_o inch_n of_o mercury_n that_o fall_v down_o yet_o the_o pressure_n of_o they_o upon_o the_o surface_n s_o be_v as_o much_o we_o see_v five_o that_o 14_o inch_n of_o water_n that_o be_v â—_o body_n fourteen_o time_n light_a than_o mercury_n may_v have_v as_o much_o weight_n with_o they_o as_o 14_o ounce_n of_o mercury_n we_o see_v sixthly_a that_o a_o cylinder_n of_o mercury_n can_v be_v suspend_v in_o air_n or_o in_o water_n unless_o it_o be_v guard_v with_o a_o tub_n to_o preserve_v it_o from_o the_o downward_o pressure_n of_o that_o air_n or_o water_n for_o by_o open_v a_o hole_n in_o q_o the_o meâ—cury_n subside_v we_o see_v seventhly_a that_o it_o be_v impossible_a 〈…〉_z fluids_n to_o suspend_v one_o another_o mutual_o unless_o there_o be_v a_o sort_n of_o equipondium_fw-la between_o they_o because_o no_o soon_o you_o destroy_v the_o equipondium_fw-la between_o the_o 42_o inch_n of_o mercury_n q_o s_o and_o the_o part_n of_o the_o surface_n s_o by_o the_o ingress_n of_o the_o water_n q_o o_fw-fr but_o assoon_o there_o arise_v a_o new_a one_o we_o see_v eighthly_a as_o we_o note_v before_o the_o near_a a_o body_n come_v to_o be_v equal_o press_v with_o a_o fluid_a the_o less_o be_v the_o pressure_n of_o that_o fluid_a sensible_a because_o less_o weight_n be_v require_v in_o the_o balance_n to_o counterpoise_v the_o pressure_n and_o weight_n of_o the_o water_n r_o q_n after_o the_o ingress_n of_o the_o water_n q_o o_fw-fr p_o than_o after_o the_o ingress_n of_o the_o water_n q_o o._n we_o see_v ninthly_a that_o when_o a_o body_n be_v equal_o and_o uniform_o preâ—â—ed_v with_o a_o fluid_a the_o pressure_n be_v insensible_a because_o after_o the_o water_n have_v thrust_v down_o all_o the_o mercury_n from_o q_o to_o saint_n there_o be_v no_o more_o weight_n at_o all_o of_o the_o water_n r_o q_o find_v in_o the_o balance_n we_o see_v tenthly_a that_o not_o only_o in_o water_n the_o pressure_n of_o water_n may_v be_v find_v but_o out_o of_o it_o namely_o in_o the_o air_n as_o be_v clear_a from_o the_o balance_n that_o support_v the_o pressure_n of_o the_o water_n r_o q._n we_o see_v eleventhly_o a_o ground_n to_o distinguish_v between_o the_o natural_a balance_n and_o the_o artificial_a balance_n the_o artificial_a balance_n be_v the_o balance_n k_o l_o the_o natural_a be_v the_o pipe_n q_o s._n we_o see_v 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surface_n be_v i_o h_o k._n and_o l_o m_o be_v the_o ground_n of_o it_o c_o d_o be_v a_o piece_n of_o brass_n 30_o inch_n high_a and_o 12_o inch_n in_o diameter_n suspend_v upon_o the_o imaginary_a surface_n of_o water_n a_o n_o b_o which_o be_v distant_a from_o the_o top_n i_o h_n k_n 25_o foot_n this_o brass_n can_v go_v far_o down_o when_o demit_v from_o h_n because_o it_o be_v keep_v up_o by_o the_o force_n and_o pressure_n of_o the_o surface_n of_o water_n a_o n_o b_o which_o i_o prove_v thus_o the_o part_n b_o sustain_v the_o facto_fw-la a_o pillar_n of_o water_n k_o b_o 1400_o pound_n weight_n therefore_o the_o part_n n_o be_v able_a to_o sustain_v as_o much_o i_o suppose_v here_o the_o say_a piece_n of_o brass_n to_o weigh_v 1400_o pound_n the_o water_n k_o b_o be_v 1400_o pound_n because_o its_o a_o pillar_n 25_o foot_n high_a and_o 12_o inch_n thick_a for_o one_o cubical_a foot_n weigh_v 56_o pound_n trois_fw-fr the_o connexion_n of_o the_o argument_n be_v evident_a because_o 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at_o 25_o foot_n from_o the_o top_n i_o answer_v because_o the_o potentia_fw-la of_o the_o surface_n a_o n_o b_o be_v equal_a to_o the_o pondus_fw-la of_o the_o brass_n to_o evidence_n this_o consider_v that_o brass_n be_v a_o body_n natural_o heavy_a than_o water_n i_o shall_v suppose_v ten_o time_n that_o be_v to_o say_v one_o inch_n of_o brass_n will_v counterpoise_v ten_o inch_n of_o water_n if_o this_o inequality_n be_v then_o must_v this_o pillar_n of_o brass_n go_v so_o much_o far_o down_o than_o the_o first_o surface_n i_o h_n k_o as_o the_o one_o be_v heavy_a in_o specie_fw-la or_o natural_o than_o the_o other_o therefore_o it_o
must_v sink_v 25_o foot_n exact_o see_v a_o piece_n of_o brass_n 30_o inch_n high_a require_v 400_o inch_n of_o water_n or_o 25_o foot_n to_o counterpoise_v it_o for_o if_o one_o inch_n of_o brass_n require_v ten_o inch_n of_o water_n then_o sure_o 30_o inch_n must_v require_v 300._o yet_o it_o be_v no_o matter_n what_o the_o thickness_n be_v provide_v it_o be_v no_o high_o than_o 30_o inch_n to_o advance_v some_o far_a let_v we_o make_v a_o second_o supposition_n namely_o while_o the_o brass_n be_v thus_o suspend_v upon_o the_o surface_n a_o n_o b_o suppose_v the_o air_n to_o come_v down_o and_o fill_v up_o the_o imaginary_a space_n e_o f_o then_o must_v the_o brass_n be_v thrust_v down_o as_o far_o as_o the_o surface_n o_o p_o that_o be_v 34_o foot_n below_o the_o surface_n a_o n_o d_o and_o 59_o from_o the_o top_n the_o reason_n of_o it_o be_v this_o because_o the_o weight_n of_o the_o air_n superad_v be_v equivalent_a to_o the_o pressure_n of_o a_o pillar_n of_o mercury_n 29_o inch_n high_a and_o 12_o inch_n thick_a therefore_o the_o brass_n be_v burden_v with_o this_o it_o must_v go_v so_o far_o down_o till_o it_o meet_v with_o a_o surface_n who_o potentia_fw-la be_v equal_a in_o weight_n to_o the_o pondus_fw-la of_o both_o which_o be_v precise_o 59_o foot_n from_o the_o top_n for_o if_o one_o inch_n of_o mercury_n require_v 14_o of_o water_n than_o 29_o inch_n must_v require_v 405_o inch_n or_o 34_o foot_n in_o a_o word_n it_o must_v go_v as_o far_o down_o as_o that_o surface_n that_o sustain_v a_o pillar_n of_o water_n that_o will_v counterpoise_v in_o a_o balance_n the_o brass_n c_o d_o and_o a_o pillar_n of_o mercury_n 29_o inch_n high_a and_o 12_o inch_n thick_a both_o which_o weigh_v 3290_o pound_n from_o what_o be_v say_v we_o see_v first_o that_o of_o two_o heavy_a body_n differ_v in_o weight_n the_o light_a may_v go_v further_o down_o than_o the_o heavy_a this_o be_v clear_a because_o a_o slender_a cylinder_n of_o gold_n in_o form_n of_o a_o arrow_n half_o a_o inch_n thick_a and_o 28_o inch_n long_o weigh_v 28_o pound_n it_o be_v no_o matter_n though_o the_o just_a weight_n of_o it_o be_v not_o determine_v will_v go_v down_o 35_o foot_n in_o water_n before_o it_o meet_v with_o a_o surface_n who_o potentia_fw-la be_v equal_a in_o weight_n to_o its_o own_o pondus_fw-la for_o if_o gold_n be_v 15_o time_n heavy_a natural_o than_o water_n than_o the_o say_v cylinder_n must_v go_v down_o before_o it_o rest_v 420_o inch_n or_o 35_o foot_n but_o a_o piece_n of_o gold_n 12_o inch_n long_o and_o six_o inch_n thick_a that_o perhaps_o will_v weigh_v 208_o pound_n will_v sink_v no_o further_o than_o 15_o foot_n and_o the_o reason_n be_v because_o if_o one_o inch_n of_o gold_n require_v 15_o of_o water_n to_o counterpoise_v it_o then_z 12_o must_v only_o require_v 180_o or_o 15_o foot_n note_v that_o both_o the_o body_n must_v go_v down_o perpendicular_o and_o not_o as_o it_o be_v horizontal_o with_o their_o side_n downmost_a for_o if_o they_o go_v down_o after_o this_o manner_n they_o can_v sink_v so_o far_o the_o reason_n of_o this_o be_v also_o evident_a because_o a_o heavy_a body_n go_v so_o far_o down_o and_o no_o further_o till_o it_o have_v thrust_v â—s_v much_o water_n out_o of_o its_o place_n as_o will_v counterpoise_v itself_o in_o a_o balance_n that_o be_v to_o say_v if_o a_o heavy_a body_n weigh_v 100_o pound_n it_o must_v go_v no_o further_o down_o than_o after_o it_o have_v thrust_v out_o 100_o pound_n of_o water_n but_o so_o it_o be_v that_o a_o piece_n of_o gold_n in_o form_n of_o a_o arrow_n go_v down_o side-wise_a or_o with_o the_o two_o end_n parallel_v to_o the_o horizon_n will_v thrust_v as_o much_o water_n out_o of_o its_o place_n as_o will_v be_v the_o weight_n of_o itself_o before_o it_o can_v go_v down_o 15_o or_o 16_o inch_n from_o the_o top_n because_o for_o every_o inch_n it_o go_v down_o side-wise_a it_o expel_v 28_o inch_n of_o water_n in_o go_v down_o two_o inch_n it_o expel_v 56._o in_o go_v down_o three_o inch_n it_o expel_v 84_o and_o so_o forward_o till_o it_o go_v down_o 15_o inch_n where_o it_o expel_v 420_o inch_n but_o 420_o inch_n amount_v to_o 35_o foot_n now_o take_v a_o cylinder_n of_o water_n 35_o foot_n high_a and_o just_a the_o thickness_n of_o the_o cylinder_n of_o gold_n which_o i_o suppose_v to_o be_v of_o half_a a_o inch_n and_o put_v they_o in_o a_o balance_n and_o you_o will_v find_v the_o one_o just_a the_o weight_n of_o the_o other_o neither_o can_v the_o piece_n of_o gold_n go_v so_o far_o down_o as_o before_o if_o it_o go_v down_o side-wise_a because_o for_o every_o six_o inch_n it_o be_v drown_v it_o expel_v a_o bulk_n of_o water_n 12_o inch_n long_o and_o six_o inch_n thick_a therefore_o it_o must_v be_v suspend_v before_o it_o go_v beyond_o 90_o inch_n or_o seven_o foot_n and_o a_o half_a now_o if_o six_o inch_n give_v one_o foot_n 90_o inch_n will_v give_v 15_o foot_n but_o 15_o of_o water_n in_o height_n and_o six_o inch_n thick_a be_v the_o just_a weight_n of_o it_o in_o a_o balance_n viz._n 208_o pound_n we_o see_v second_o the_o broad_a and_o large_a the_o surface_n of_o a_o fluid_a be_v it_o be_v the_o more_o able_a and_o strong_a to_o support_v a_o heavy_a burden_n therefore_o the_o part_n of_o a_o surface_n of_o water_n six_o inch_n square_v every_o way_n will_v carry_v a_o far_o great_a weight_n than_o a_o part_n four_o inch_n square_a though_o a_o surface_n of_o water_n 34_o or_o 35_o foot_n deep_a be_v not_o able_a to_o sustain_v a_o cylinder_n of_o gold_n if_o it_o exceed_v 28_o or_o 29_o inch_n in_o height_n yet_o take_v a_o cylinder_n of_o gold_n 10_o foot_n high_a and_o reduce_v it_o by_o make_v it_o thick_a to_o the_o height_n of_o 20_o inch_n a_o surface_n of_o water_n little_o more_o than_o 24_o foot_n deep_o will_v sustain_v it_o or_o reduce_v a_o cylinder_n 10_o foot_n high_a which_o require_v a_o surface_n more_o than_o 100_o foot_n deep_a to_o a_o cylinder_n six_o inch_n high_a a_o surface_n little_o more_o than_o seven_o foot_n deep_o will_v support_v it_o we_o see_v three_o the_o reason_n why_o body_n that_o be_v broad_a and_o large_a move_v â—lowlier_o through_o air_n and_o water_n than_o body_n that_o be_v more_o thin_a and_o slender_a though_o both_o be_v of_o the_o same_o weight_n in_o a_o balance_n for_o example_n 20_o pound_n of_o lead_n long_o and_o slender_a like_o a_o arrow_n will_v go_v soon_o to_o the_o ground_n of_o a_o deep_a water_n than_o a_o piece_n of_o lead_n of_o the_o same_o weight_n in_o form_n of_o a_o platter_n or_o bason_n the_o reason_n be_v because_o as_o the_o body_n be_v broad_a so_o it_o take_v a_o broad_a part_n of_o a_o surface_n which_o broad_a part_n be_v strong_a and_o able_a than_o a_o narrow_a part_n and_o so_o make_v the_o great_a resistance_n the_o same_o be_v the_o reason_n why_o a_o bullet_n six_o inch_n in_o diameter_n move_v â—lowlier_a through_o the_o air_n shoot_v from_o a_o cannon_n than_o a_o bullet_n one_o inch_n in_o diameter_n for_o the_o same_o reason_n ship_n of_o seven_o or_o eight_o hundred_o tun_n move_v far_o slowly_o through_o the_o air_n and_o water_n than_o vessel_n of_o less_o burden_n item_n large_a and_o big_a fowl_n as_o eagle_n move_v slowly_o than_o small_a bird_n as_o swallow_n yea_o of_o fowl_n of_o the_o same_o quantity_n one_o may_v move_v quick_o than_o another_o as_o be_v evident_a in_o long-winged_a hawk_n as_o falcon_n that_o by_o the_o sharpness_n of_o their_o wing_n move_v far_o more_o space_n in_o half_a a_o hour_n than_o kite_n or_o gosehawk_n who_o wing_n be_v round_a we_o see_v four_a that_o there_o be_v no_o body_n how_o heavy_a soever_o but_o it_o may_v be_v support_v by_o the_o surface_n of_o a_o fluid_a either_o in_o air_n or_o in_o water_n i_o grant_v the_o strong_a surface_n of_o air_n that_o can_v be_v have_v be_v not_o able_a to_o support_v more_o weight_n than_o a_o cylinder_n of_o gold_n 28_o inch_n high_a yet_o though_o it_o be_v as_o large_a and_o broad_a as_o a_o millstone_n if_o it_o do_v not_o exceed_v the_o say_a height_n the_o air_n be_v able_a to_o sustain_v it_o for_o the_o same_o cause_n if_o it_o be_v possible_a to_o free_v a_o millstone_n of_o the_o air_n that_o rest_v upon_o it_o the_o air_n below_o will_v lift_v it_o from_o the_o ground_n and_o carry_v it_o up_o many_o fathom_n even_o till_o it_o come_v to_o a_o surface_n equal_a in_o power_n to_o the_o weight_n of_o the_o stone_n or_o if_o a_o large_a millstone_n be_v demit_v from_o the_o top_n of_o the_o atmosphere_n towards_o the_o earth_n it_o can_v hardly_o
six_o inch_n thick_a but_o this_o seem_v rather_o to_o flow_v from_o the_o disproportion_n of_o magnitude_n see_v a_o circular_a plain_a 4_o inch_n in_o diameter_n can_v receive_v a_o base_a of_o a_o pillar_n 6_o inch_n in_o diameter_n but_o this_o be_v certain_a from_o the_o very_a nature_n of_o fluids_n that_o in_o a_o deep_a water_n wherein_o may_v be_v distinguish_v 100_o or_o 1000_o different_a surface_n each_o one_o be_v able_a to_o support_v his_o own_o burden_n and_o no_o more_o experiment_n xiii_o figure_n 17_o 18_o 19_o for_o make_v this_o experiment_n take_v two_o plain_a body_n of_o brass_n or_o marble_n well_o polish_v make_v they_o of_o any_o quantity_n but_o for_o this_o present_a use_n let_v each_o of_o they_o be_v four_o inch_n broad_a square-wise_a upon_o the_o back_n part_n let_v each_o one_o have_v a_o handle_n about_o six_o inch_n long_o of_o the_o same_o metal_n form_v with_o the_o plain_n itself_o in_o the_o sound_n if_o they_o be_v of_o brass_n as_o be_v represent_v in_o this_o schematism_n when_o they_o be_v thus_o prepare_v anoint_v their_o inner-side_n with_o oil_n or_o water_n and_o have_v thrust_v the_o one_o face_n alongst_o upon_o the_o other_o with_o all_o the_o strength_n you_o have_v till_o all_o the_o four_o edge_n agree_v two_o whereof_o be_v represent_v by_o a_o b_o and_o c_o d_o you_o will_v find_v they_o cleave_v so_o close_o together_o as_o if_o they_o be_v but_o one_o body_n the_o effect_n be_v this_o that_o ordinary_a strength_n will_v not_o pull_v they_o asunder_o and_o that_o under_o a_o surface_n of_o water_n a_o strong_a pull_n be_v require_v than_o in_o the_o air._n that_o we_o may_v deduce_v some_o hydrostatical_a conclusion_n from_o this_o experiment_n let_v we_o suppose_v these_o two_o plain_a body_n to_o be_v unite_v in_o the_o middle_n of_o the_o water_n i_o k_n p_o qui_fw-fr that_o be_v 34_o foot_n deep_a and_o suspend_v by_o a_o beam_n or_o long_a tree_n t_o v_n exist_v in_o the_o air_n near_o the_o top_n of_o the_o water_n by_o a_o chord_n s_o e_z pass_v between_o the_o middle_n of_o the_o beam_n and_o the_o end_n of_o the_o handle_n at_o e._n suppose_v next_o a_o great_a weight_n of_o lead_n r_o 350_o pound_n to_o be_v append_v to_o the_o end_n of_o the_o handle_n at_o h_n of_o the_o under_o plain_a body_n c_o d_o n_o o._n this_o do_v i_o affirm_v that_o the_o beam_n t_o v_n neither_o sustain_v the_o under_o plain_a body_n c_o d_o n_o o_o g_o h_n not_o the_o 350_o pound_n weight_n of_o lead_n r_o that_o hang_v down_o from_o the_o handle_n g_o h._n if_o it_o be_v object_v that_o the_o beam_n support_v the_o upper_a plain_a body_n a_o b_o l_o m_o f_o e_o therefore_o it_o must_v bear_v the_o weight_n also_o of_o the_o under_o plain_a c_o d_o n_o o_o g_o h_n with_o the_o weight_n r_o see_v they_o be_v both_o unite_v together_o and_o cleave_v so_o close_o as_o if_o they_o be_v but_o one_o body_n i_o answer_v it_o support_v the_o one_o unquestionable_o but_o not_o the_o other_o to_o explicate_v this_o hydrostatical_a mystery_n i_o must_v aver_v three_o thing_n first_o that_o the_o inferior_a plain_n be_v support_v by_o the_o upward_a pressure_n 〈◊〉_d the_o low_a water_n p_o q_o n_o o._n second_o that_o the_o burden_n which_o the_o beam_n sustain_v be_v not_o the_o weight_n of_o the_o under_o plain_a but_o the_o weight_n of_o the_o 34_o foot_n of_o water_n i_o k_o l_o m._n three_o that_o this_o weight_n be_v exact_o the_o weight_n of_o the_o inferior_a plain_n and_o lead_v r._n but_o be_v it_o not_o more_o easy_a to_o say_v that_o the_o beam_n support_v both_o the_o plain_n i_o answer_v if_o i_o say_v so_o i_o can_v neither_o affirm_v truth_n nor_o speak_v consequential_o but_o may_v it_o not_o be_v say_v that_o the_o inferior_a plain_n be_v support_v both_o by_o the_o beam_n and_o the_o low_a water_n p_o q_o n_o o?_o i_o answer_v this_o be_v impossible_a because_o one_o and_o the_o same_o weight_n can_v be_v support_v total_o by_o two_o distinct_a supporter_n for_o make_v these_o assertion_n evident_a i_o must_v suppose_v the_o superior_a water_n i_o k_o l_o m_o to_n be_v 34_o foot_n deep_a and_o to_o weigh_v if_o it_o be_v put_v into_o a_o balance_n 400_o pound_n and_o which_o be_v unquestionable_a that_o the_o say_a water_n rest_v upon_o the_o back_n of_o the_o superior_a plain_n l_o m._n i_o suppose_v second_o that_o the_o low_a water_n p_o q_o n_o o_o weigh_v as_o much_o and_o thrust_v up_o the_o inferior_a plain_n with_o as_o great_a weight_n as_o the_o superior_a plain_n be_v press_v down_o with_o by_o the_o superior_a water_n this_o be_v evident_a from_o former_a experiment_n and_o last_o i_o suppose_v each_o plain_n to_o weigh_v two_o pound_n and_o the_o weight_n of_o lead_n r_o 350._o it_o be_v to_o be_v observe_v here_o that_o no_o mistake_n may_v arise_v in_o the_o calculation_n afterward_o that_o though_o it_o be_v say_v this_o 34_o foot_n of_o water_n weigh_v 400_o pound_n yet_o in_o itself_o it_o weigh_v but_o 200_o but_o consider_v the_o pressure_n of_o the_o air_n upon_o i_o k_o which_o be_v as_o much_o it_o may_v be_v true_o say_v to_o weigh_v 400._o these_o thing_n be_v premit_v i_o say_v the_o weight_n that_o the_o beam_n t_o v_n sustain_v be_v not_o the_o weight_n of_o the_o inferior_a plain_n and_o the_o lead_n r_o but_o 352_o pound_n of_o the_o superior_a water_n i_o k_o l_o m_o and_o consequent_o that_o the_o inferior_a plain_n be_v support_v by_o the_o low_a water_n p_o q_o n_o o._n the_o reason_n be_v because_o the_o low_a water_n press_v up_o â—â—th_o the_o weight_n of_o 48_o pound_n it_o be_v in_o itself_o 400_o pound_n but_o be_v burden_v with_o 352_o it_o can_v thrust_v up_o with_o more_o weight_n than_o 48._o now_o it_o press_v up_o with_o 48_o must_v ease_v the_o beam_n of_o 48_o and_o counterpoise_v so_o much_o of_o the_o superior_a water_n and_o consequent_o the_o beam_n must_v support_v only_o 352_o pound_n of_o it_o but_o put_v the_o case_n you_o say_v the_o weight_n r_o be_v 130_o pound_n 160_o pound_n or_o 180_o pound_n will_v the_o beam_n be_v less_o or_o more_o burden_a with_o the_o superior_a water_n i_o answer_v if_o r_o be_v 130_o pound_n than_o the_o beam_n support_v only_o 132_o pound_n of_o the_o superior_a water_n for_o if_o the_o inferior_a be_v only_o burden_v with_o 130_o the_o weight_n of_o r_o and_o with_o two_o the_o weight_n of_o the_o inferior_a plain_n then_o must_v it_o press_v up_o with_o 368_o and_o by_o this_o mean_n must_v ease_v the_o beam_n of_o so_o much_o it_o sustain_v 132_o pound_n only_o according_a to_o this_o count_a when_o the_o lead_n r_o weigh_v 160_o pound_n the_o beam_n support_v only_o 238_o pound_n of_o the_o superior_a water_n if_o it_o weigh_v 180_o pound_n it_o sustain_v 218._o and_o if_o the_o weight_n r_o be_v take_v away_o the_o beam_n support_v no_o more_o of_o the_o superior_a water_n than_o two_o pound_n to_o proceed_v a_o little_a further_o imagine_v the_o two_o plain_n to_o be_v draw_v up_o 17_o foot_n near_o the_o first_o surface_n i_o k_o namely_o as_o high_a as_o z_o w._n this_o do_v the_o union_n break_v up_o and_o they_o present_o fall_v asunder_o the_o reason_n be_v because_o the_o surface_n z_o w_n be_v not_o able_a to_o support_v 352_o pound_n but_o only_o 300_o which_o i_o prove_v thus_o if_o 68_o foot_n sustain_v 400_o than_o 51_o foot_n must_v sustain_v 300._o i_o say_v 68_o and_o not_o 34_o because_o as_o be_v note_v the_o pressure_n of_o the_o air_n upon_o the_o surface_n i_o k_n be_v equivalent_a to_o other_o 34_o foot_n and_o therefore_o though_o the_o deepness_n of_o this_o water_n between_o i_o k_o and_o l_o m_o be_v but_o 34_o foot_n real_o yet_o it_o be_v 68_o foot_n virtual_o and_o in_o effect_n imagine_v second_o the_o surface_n i_o k_o to_o subside_v 17_o foot_n namely_o to_o z_o w._n in_o this_o case_n the_o union_n be_v break_v also_o and_o the_o low_a plain_n fall_v from_o the_o upper_a the_o reason_n of_o this_o be_v the_o same_o with_o the_o former_a because_o by_o what_o proportion_n you_o diminish_v the_o high_a of_o the_o superior_a water_n by_o that_o same_o proportion_n you_o diminish_v the_o upward_a pressure_n of_o the_o low_a water_n therefore_o if_o you_o subtract_v from_o the_o superior_a water_n 17_o foot_n that_o weigh_v 100_o pound_n you_o subtract_v likewise_o 100_o pound_n from_o the_o inferior_a water_n and_o consequent_o you_o make_v it_o press_v up_o only_o with_o 300_o but_o 300_o be_v not_o able_a to_o counterpoise_v 352._o let_v we_o suppose_v three_o the_o superior_a plain_n and_o the_o superior_a water_n to_o be_v annihilate_v then_o i_o say_v the_o
plain_n have_v as_o many_o hole_n cut_v through_o it_o answer_v to_o the_o four_o of_o the_o nether_a second_o what_o will_v follow_v if_o the_o nether_a plain_n be_v entire_a and_o four_o bore_v through_o the_o upper_a but_o i_o shall_v supersede_n and_o leave_v these_o to_o be_v gather_v by_o the_o judicious_a reader_n from_o this_o experiment_n we_o see_v first_o that_o the_o broad_a and_o large_a a_o surface_n of_o a_o fluid_a be_v it_o be_v the_o more_o able_a to_o sustain_v a_o burden_n and_o the_o narrow_a it_o be_v it_o be_v the_o less_o able_a second_o that_o each_o part_n of_o a_o surface_n be_v able_a to_o sustain_v so_o much_o weight_n and_o no_o more_o and_o no_o less_o from_o what_o be_v say_v we_o shall_v only_o inâ—err_v this_o conclusion_n that_o equality_n of_o height_n between_o pillar_n of_o a_o fluid_a make_v equal_a pressure_n and_o inequality_n of_o height_n make_v unequal_a pressure_n therefore_o it_o be_v no_o matter_n whether_o they_o be_v gross_a or_o small_a thick_a or_o slender_a provide_v they_o be_v all_o of_o the_o same_o altitude_n experiment_n fourteen_o figure_n 20._o this_o schematism_n represent_v a_o vessel_n full_a of_o water_n 8_o foot_n deep_a e_o f_o be_v a_o glass-pipe_n open_a at_o both_o end_n about_o 9_o foot_n high_a and_o one_o inch_n in_o diameter_n a_o b_o c_o d_o be_v a_o vessel_n of_o glass_n or_o of_o any_o other_o metal_n through_o who_o orifice_n above_o the_o say_a pipe_n come_v down_o b_o h_n i_o be_v a_o pipe_n go_v out_o from_o the_o say_a vessel_n crooked_a with_o a_o right_a angle_n at_o h_n that_o the_o orifice_n i_o may_v look_v upward_o that_o some_o hydrostatical_a conclusion_n may_v be_v infer_v from_o this_o experiment_n fill_v the_o low_a vessel_n a_o b_o c_o d_o with_o quicksilver_n almost_o then_o pour_v in_o as_o much_o water_n above_o it_o as_o will_v fill_v the_o space_n a_o b_o h_n leave_v from_o h_n to_o i_o full_a of_o air._n next_o thrust_v down_o the_o orifice_n of_o the_o pipe_n e_o below_o the_o say_a water_n and_o mercury_n till_o it_o rest_v upon_o the_o bottom_n c_o d._n last_o stop_v well_o with_o cement_n the_o passage_n of_o the_o low_a vessel_n through_o which_o the_o pipe_n come_v down_o that_o neither_o air_n nor_o water_n may_v go_v out_o or_o come_v in_o these_o thing_n be_v do_v let_v down_o this_o engine_n to_o the_o bottom_n of_o the_o large_a vessel_n which_o as_o be_v note_v be_v full_a of_o water_n from_o m_n n_o to_o k_o l_o 8_o foot_n and_o you_o will_v find_v the_o mercury_n to_o rise_v in_o the_o pipe_n from_o a_o b_o to_z g_z 6_o inch_n and_o more_o the_o reason_n be_v because_o there_o be_v a_o pillar_n of_o water_n k_o i_o that_o enter_v the_o orifice_n i_o and_o press_v down_o the_o air_n from_o i_o to_o p_o 3_o inch_n which_o before_o be_v 6._o this_o air_n be_v so_o burden_v instant_o press_v forward_o the_o water_n h_o b_o a_o and_o this_o press_v the_o surface_n of_o the_o stagnant_a mercury_n a_o b_o cause_v the_o liquor_n run_v up_o the_o pipe_n from_o a_o b_o to_z g_z 6_o inch_n the_o reason_n why_o it_o rise_v 6_o inch_n be_v this_o between_o the_o surface_n of_o the_o stagnant_a mercury_n a_o b_o and_o the_o top_n of_o the_o water_n l_o o_fw-fr k_o be_v 84_o inch_n now_o water_n be_v 14_o time_n natural_o light_a than_o mercury_n there_o must_v be_v 14_o inch_n of_o water_n require_v for_o sustain_v one_o inch_n of_o mercury_n and_o consequent_o 84_o for_o support_v 6._o for_o a_o second_o trial_n lift_v up_o the_o whole_a engine_n to_o the_o top_n of_o the_o water_n and_o you_o will_v find_v the_o 6_o inch_n of_o mercury_n b_o g_o sink_n down_o and_o become_v no_o high_o within_o the_o pipe_n than_o the_o surface_n of_o the_o stagnant_a mercury_n a_o b_o without_o the_o reason_n be_v because_o by_o come_v up_o above_o the_o water_n the_o pressure_n of_o the_o water_n k_o i_o be_v take_v away_o from_o the_o orifice_n i_o by_o which_o mean_v the_o compress_a air_n h_n p_o extend_v itself_o to_o i_o liberat_o the_o water_n a_o b_o h_n of_o the_o pressure_n it_o have_v and_o this_o free_v the_o mercury_n of_o its_o pressure_n and_o so_o the_o 6_o inch_n fall_v down_o for_o a_o three_o trial_n stop_v close_o the_o orifice_n i_o and_o let_v all_o down_o as_o before_o in_o this_o case_n you_o will_v find_v no_o ascent_n of_o mercury_n from_o b_o to_z g_z because_o the_o water_n k_o i_o can_v have_v access_n to_o thrust_v down_o the_o air_n from_o i_o to_o p_o as_o former_o for_o a_o four_o open_v the_o say_a orifice_n i_o while_o the_o engine_n be_v below_o the_o water_n and_o you_o will_v find_v the_o mercury_n rise_v from_o b_o to_z g_z because_o the_o pillar_n of_o water_n k_o i_o have_v now_o access_n to_o press_v for_o a_o five_o trial_n stop_v the_o orifice_n i_o and_o bring_v up_o all_o to_o the_o top_n and_o you_o will_v find_v the_o six_o inch_n of_o mercury_n b_o g_z suspend_v as_o if_o the_o engine_n be_v under_o the_o water_n the_o reason_n be_v because_o the_o stop_n of_o the_o orifice_n keep_v the_o enclose_a air_n p_o h_n under_o the_o same_o degree_n of_o pressure_n it_o obtain_v from_o the_o water_n k_o i._o for_o a_o six_o proof_n open_v the_o same_o orifice_n i_o while_o the_o engine_n be_v above_o the_o water_n and_o you_o will_v find_v the_o six_o inch_n of_o mercury_n fall_v down_o because_o the_o imprison_a air_n h_n p_o obtain_v now_o its_o liberty_n and_o expand_v itself_o from_o h_n to_o i_o ease_v the_o water_n b_o h_n of_o the_o burden_n it_o be_v under_o for_o a_o seven_o pour_v in_o 14_o inch_n of_o water_n at_o the_o orifice_n f_o till_o it_o rest_v upon_o the_o top_n of_o the_o mercury_n at_o g_o and_o you_o will_v find_v one_o inch_n fall_v down_o pour_v in_o as_o much_o and_o two_o inch_n fall_v down_o in_o a_o word_n pour_v in_o as_o much_o water_n as_o will_v fill_v the_o pipe_n to_o o_o and_o you_o will_v find_v the_o whole_a six_o inch_n fall_v down_o the_o reason_n be_v because_o the_o water_n k_o i_o be_v not_o able_a to_o sustain_v both_o the_o six_o inch_n of_o mercury_n and_o the_o water_n that_o be_v pour_v in_o any_o one_o of_o they_o be_v able_a and_o sufficient_a to_o counterpoise_v it_o for_o a_o eight_o trial_n empty_z the_o pipe_n of_o the_o say_a water_n and_o after_o the_o mercury_n be_v ascend_v from_o a_o b_o to_z g_z as_o formerly_z suck_v out_o the_o whole_a air_n between_o g_z and_o f_o and_o you_o will_v find_v the_o mercury_n to_o rise_v from_o g_z to_z r_z 29_o inch_n the_o reason_n of_o this_o be_v evident_a from_o the_o pillar_n of_o air_n s_o k_n that_o rest_v upon_o the_o top_n of_o the_o pillar_n of_o water_n k_o i_o for_o by_o suck_v out_o the_o say_a air_n you_o take_v away_o the_o pondus_fw-la or_o weight_n that_o counterpoise_v the_o weight_n of_o the_o pillar_n s_o k_n therefore_o it_o find_v its_o counterpoise_n remove_v present_o cause_v the_o water_n k_o i_o to_o enter_v far_o within_o the_o crooked_a pipe_n till_o it_o have_v press_v up_o the_o liquor_n to_o r._n for_o a_o nine_o trial_n take_v the_o six_o inch_n of_o mercury_n b_o g_o and_o put_v they_o into_o the_o scale_n of_o a_o balance_n then_o take_v as_o much_o water_n as_o will_v fill_v the_o tub_n between_o a_o b_o and_o o_o and_o put_v it_o into_o the_o other_o scale_n and_o you_o will_v find_v a_o most_o exact_a counterbalance_n between_o they_o the_o reason_n be_v because_o if_o the_o water_n k_o h_n or_o a_o pillar_n of_o that_o height_n be_v able_a to_o raise_v and_o counterpoise_v the_o mercury_n b_o g_o then_o must_v as_o much_o water_n as_o fill_v the_o pipe_n between_o b_o and_o o_o be_v the_o just_a weight_n of_o it_o the_o reason_n of_o this_o consequence_n be_v because_o these_o two_o water_n be_v of_o the_o same_o weight_n therefore_o if_o the_o one_o be_v the_o just_a weight_n of_o it_o the_o other_o must_v be_v so_o too_o if_o it_o be_v say_v that_o the_o water_n that_o fill_v the_o pipe_n between_o b_o and_o o_o be_v far_o thick_a than_o the_o water_n k_o h_n therefore_o they_o can_v be_v both_o of_o one_o weight_n i_o answer_v equality_n of_o altitude_n in_o this_o balance_n of_o nature_n be_v equality_n of_o weight_n therefore_o see_v the_o one_o water_n be_v as_o high_a as_o the_o other_o they_o must_v be_v both_o of_o one_o weight_n if_o it_o be_v say_v that_o a_o pillar_n of_o water_n between_o k_o and_o h_n can_v counterpoise_v the_o six_o inch_n of_o mercury_n b_o g_o both_o be_v put_v into_o a_o balance_n and_o the_o reason_n be_v because_o the_o one_o be_v thick_a than_o the_o
k_o p_o n_o make_v a_o just_a equipondium_fw-la with_o the_o water_n e_o h_o r_o n._n three_o that_o fluid_v not_o only_o of_o the_o same_o kind_n but_o of_o different_a kind_n do_v counterpoise_v one_o another_o according_a to_o altitude_n and_o not_o according_a to_o thickness_n because_o though_o the_o mercury_n k_o p_o n_o be_v far_o thick_a than_o the_o water_n e_o h_n yet_o they_o counterbalance_v one_o another_o because_o a_o proportion_n be_v keep_v according_a to_o their_o altitude_n four_o that_o a_o fluid_a natural_o light_a may_v move_v a_o fluid_a natural_o heavy_a and_o thrust_v it_o out_o of_o its_o own_o place_n because_o the_o water_n come_v in_o at_o h_n thrust_v down_o the_o mercury_n to_o r_o and_o from_o r_z to_z n_o and_o so_o forth_o five_o that_o of_o two_o fâ—uids_n unequal_a in_o strength_n debate_v together_o the_o weak_a of_o necessity_n must_v yield_v to_o the_o strong_a though_o the_o weak_a be_n far_o heavy_a natural_o than_o the_o strong_a as_o be_v evident_a in_o the_o mercuâ—y_n that_o yield_v to_o the_o water_n six_o that_o it_o be_v impossible_a for_o two_o fluid_n so_o long_o as_o they_o be_v unequal_a in_o strength_n to_o cease_v from_o motion_n till_o they_o come_v to_o a_o equipondium_fw-la because_o the_o water_n always_o spring_v up_o through_o the_o mercury_n till_o a_o equal_a balance_n happen_v seven_o that_o one_o fluid_a of_o this_o kind_n can_v counterpoise_v another_o fluid_n of_o the_o same_o kind_n though_o there_o be_v divers_a fluids_n interveening_a because_o the_o air_n f_o e_o counterpoise_v the_o air_n i_o k_o or_o i_o s_o notwithstanding_o of_o water_n and_o mercury_n interveen_v eight_o that_o there_o may_v be_v as_o much_o pressure_n in_o one_o inch_n of_o a_o fluid_a as_o in_o a_o million_o because_o the_o 29_o inch_n of_o air_n i_o saint_n have_v as_o much_o bensil_n in_o they_o as_o be_v in_o the_o whole_a pillar_n of_o air_n e_o f_o that_o go_v up_o from_o the_o top_n of_o the_o water_n to_o the_o top_n of_o the_o atmosphere_n nine_o that_o when_o one_o fluid_a be_v under_o pressure_n the_o next_o must_v be_v under_o the_o same_o degree_n of_o pressure_n though_o they_o be_v not_o of_o the_o same_o kind_n but_o of_o different_a sort_n because_o the_o air_n i_o s_o the_o water_n s_o k_n and_o mercury_n k_o p_o be_v sure_o under_o the_o same_o degree_n of_o pressure_n otherwise_o the_o motion_n can_v not_o end_v ten_o that_o when_o two_o fluid_n of_o divers_a kind_n do_v press_v one_o another_o that_o which_o be_v natural_o light_a ascend_v always_o to_o the_o high_a place_n and_o the_o heavy_a to_o the_o low_a because_o the_o air_n i_o s_o be_v above_o the_o water_n s_o k_n and_o the_o water_n s_o k_n be_v above_o the_o mercury_n note_v that_o this_o be_v not_o universal_a but_o only_o happen_v when_o the_o light_a cylinder_n be_v slendere_a than_o the_o other_o for_o if_o the_o mercury_n k_o p_o be_v no_o thick_a than_o the_o water_n p_o n_o r_o h_n this_o will_v raise_v it_o entire_o eleven_o that_o the_o compression_n of_o air_n to_o less_o space_n be_v not_o according_a to_o arithmetical_a progression_n 1_o 2_o 3_o 4_o 5_o but_o according_a to_o some_o other_o proportion_n which_o may_v be_v call_v uniform-difform_a note_v here_o that_o though_o this_o be_v true_a of_o the_o air_n while_o it_o be_v compress_v from_o a_o more_o quantity_n to_o a_o less_o as_o here_o or_o in_o a_o windgun_n yet_o it_o be_v not_o true_a of_o the_o pressure_n of_o the_o element_n of_o air_n which_o be_v more_o and_o more_o from_o the_o top_n of_o the_o atmosphere_n to_o the_o earth_n according_a to_o arithmetical_a progression_n as_o in_o water_n we_o see_v last_o that_o the_o heavy_a of_o fluid_n such_o as_o mercury_n press_v upward_o as_o well_o as_o downward_o because_o the_o top_n of_o the_o mercury_n k_o thrust_v up_o the_o water_n k_o s_o as_o well_o as_o it_o thrust_v down_o the_o water_n p_o n_o r_o h._n it_o may_v be_v inquire_v here_o how_o far_o this_o glass_n will_v go_v down_o before_o the_o 29_o inch_n of_o air_n i_o k_o be_v reduce_v to_o one_o inch_n i_o answer_v its_o hard_a to_o determine_v but_o it_o seem_v it_o ought_v to_o go_v down_o more_o than_o 300_o fathom_n in_o this_o case_n there_o will_v be_v 28_o inch_n of_o water_n above_o k._n let_v we_o suppose_v the_o orifice_n h_n to_o be_v stop_v at_o that_o deepness_n and_o the_o glass_n bring_v above_o the_o water_n then_o when_o the_o say_a orifice_n be_v open_v in_o the_o air_n you_o will_v find_v the_o whole_a water_n p_o n_o r_o h_n thrust_v out_o and_o not_o only_o this_o but_o the_o whole_a mercury_n p_o k_n spring_v out_o at_o the_o orifice_n h_n likewise_o except_o a_o little_a that_o remain_v between_o n_o and_o h_n the_o reason_n be_v because_o the_o 29_o inch_n of_o air_n be_v reduce_v to_o one_o will_v be_v under_o a_o very_a great_a bensil_n therefore_o the_o weight_n be_v take_v away_o that_o beget_v it_o of_o its_o own_o accord_n it_o will_v expand_v itself_o to_o its_o old_a dimension_n which_o it_o can_v not_o do_v unless_o both_o the_o 28_o inch_n of_o water_n that_o be_v suppose_v to_o be_v above_o k_o and_o the_o mercury_n k_o p_o be_v thrust_v out_o of_o their_o place_n experiment_n xvi_o figure_n 22._o this_o schematism_n represent_v a_o vessel_n full_a of_o water_n 84_o inch_n deep_a namely_o from_o l_o n_o the_o first_o surface_n to_o m_o r_o the_o bottom_n from_o m_n to_o r_o in_o breadth_n be_v 20_o inch_n there_o be_v here_o also_o two_o glass-pipe_n open_a at_o both_o end_n the_o one_o two_o inch_n wide_a the_o other_o half_o a_o inch_n wide_a both_o of_o they_o be_v 85_o inch_n long_o x_o in_n o_o be_v a_o surface_n of_o stagnant_a mercury_n among_o which_o the_o two_o end_n of_o the_o pipe_n be_v drown_v e_o c_o be_v a_o pillar_n of_o mercury_n six_o inch_n in_o height_n and_o so_o be_v g_o d_o both_o of_o they_o raise_v to_o that_o altitude_n by_o the_o pressure_n of_o the_o water_n upon_o the_o surface_n x_o y_o o._n the_o pillar_n e_o c_o at_fw-fr be_v support_v by_o and_o rest_v upon_o the_o imaginary_a pillar_n a_o p._n and_o so_o be_v the_o pillar_n g_o d_o b_o support_v by_o the_o pillar_n b_o q._n there_o be_v three_o thing_n that_o occur_v here_o from_o this_o operation_n of_o nature_n to_o be_v inquire_v after_o first_o why_o ought_v the_o mercury_n to_o rise_v in_o the_o two_o tub_n after_o the_o vessel_n be_v fill_v with_o water_n second_o why_o rather_o six_o inch_n than_o seven_o or_o eight_o three_o what_o be_v the_o reason_n why_o it_o rise_v as_o high_a in_o the_o wide_a tâ—b_n as_o in_o the_o narrow_a i_o answer_v the_o mercury_n rise_v from_o c_o to_z e_z and_o from_o d_o to_z g_z by_o the_o pressure_n of_o the_o water_n that_o rest_v upon_o the_o surface_n x_o y_o o._n before_o that_o the_o water_n be_v pour_v into_o the_o vessel_n there_o be_v here_o a_o most_o equal_a and_o uniform_a pressure_n upon_o the_o surface_n x_o in_n o_o both_o without_o and_o within_o the_o tub_n namely_o from_o the_o air_n that_o rest_v upon_o it_o but_o no_o soon_o be_v the_o water_n pour_v in_o but_o as_o soon_o the_o pressure_n become_v unequal_a the_o part_n of_o the_o surface_n without_o the_o tub_n be_v more_o burden_v than_o the_o part_n c_o and_o d_o within_o therefore_o the_o part_n that_o be_v less_o press_v must_v rise_v and_o climb_v up_o till_o the_o pressure_n become_v equal_a for_o it_o be_v impossible_a that_o a_o fluid_a can_v cease_v from_o motion_n so_o long_o as_o there_o be_v inequality_n of_o weight_n between_o the_o pondus_fw-la and_o the_o potentia_fw-la if_o any_o doubt_n let_v he_o pierce_v the_o side_n of_o the_o vessel_n and_o when_o the_o whole_a water_n be_v run_v out_o he_o will_v find_v e_o c_o and_o g_o d_o to_n have_v fall_v down_o which_o clear_o prove_v the_o climb_n up_o of_o the_o mercury_n to_o depend_v upon_o the_o inpouring_a of_o the_o water_n for_o understand_v the_o reason_n of_o the_o second_o remember_v that_o mercury_n as_o we_o have_v often_o note_v be_v count_v 14_o time_n heavy_a than_o water_n therefore_o e_z c_z must_v be_v six_o inch_n see_v x_o in_n o_o be_v press_v with_o the_o altitude_n of_o 84_o inch_n of_o water_n it_o will_v be_v judge_v no_o marvel_n to_o see_v the_o mercury_n rise_v from_o c_o to_z e_z and_o from_o d_o to_z g_z provide_v the_o face_n of_o the_o stagnant_a mercury_n be_v as_o high_a as_o z_o f._n no_o more_o strange_a it_o be_v to_o see_v the_o two_o mercury_n rise_v with_o the_o pressure_n of_o the_o water_n for_o in_o effect_n and_o real_o the_o say_a water_n be_v the_o just_a weight_n of_o as_o
much_o mercury_n as_o will_v fill_v between_o x_o o_o and_o z_o f._n for_o understand_v the_o three_o remember_v as_o be_v note_v before_o that_o fluid_a body_n counterpoise_v one_o another_o only_o according_a to_o altitude_n therefore_o it_o be_v no_o matter_n whether_o the_o tub_n be_v wide_a or_o narrow_a if_o it_o be_v inquire_v how_o can_v one_o and_o the_o â—ame_n water_n counterpoise_v two_o fluid_n of_o different_a weight_n to_o say_v that_o fluids_n counterpoise_n one_o another_o according_a to_o altitude_n do_v not_o clear_a the_o difficulty_n for_o it_o still_o remain_v to_o be_v ask_v why_o they_o counterpoise_v one_o another_o after_o this_o manner_n therefore_o it_o seem_v that_o if_o the_o water_n raise_v the_o mercury_n from_o c_o to_o e_z in_o the_o wide_a pipe_n it_o must_v raise_v it_o in_o the_o narrow_a one_o from_o d_o to_o k._n for_o answer_v consider_v first_o that_o as_o there_o be_v here_o two_o pillar_n of_o mercury_n c_o e_o and_o d_o g_z within_z the_o two_o tub_n so_o there_o be_v here_o also_o two_o pillar_n of_o mercury_n a_o p_o and_o b_o q_o under_o the_o two_o orifice_n upon_o which_o the_o say_v two_o pillar_n stand_v and_o rest_n consider_v second_o that_o the_o potentia_fw-la or_o force_n of_o the_o pillar_n a_o p_o be_v just_o equal_a to_o the_o pondus_fw-la of_o the_o pillar_n e_o c_o a_o item_n that_o the_o potentia_fw-la of_o the_o pillar_n b_o q_n be_v equal_a to_o the_o pondus_fw-la g_o d_o b._n three_o that_o the_o potentia_fw-la of_o a_o p._n be_v most_o exact_o equal_v to_o the_o potentia_fw-la of_o b_o q_o and_o the_o reason_n be_v because_o their_o top_n a_o and_o b_o be_v part_n of_o the_o same_o horizontal_a surface_n i_o say_v then_o if_o a_o p_o be_v equal_a to_o e_o c_o a_o and_o b_o qui_fw-fr equal_a to_o g_o d_o b_o and_o a_o p_o and_o b_o q_n equal_a among_o themselves_o then_o must_v e_o c_o at_fw-fr be_v equal_a to_o g_o d_o b._n the_o same_o water_n then_o do_v not_o counterpoise_v two_o body_n of_o different_a weight_n i_o grant_v e_o c_o a_o to_o be_v far_o heavy_a than_o g_o d_o b_o while_o they_o be_v weigh_v in_o a_o pair_n of_o scale_n but_o the_o one_o be_v not_o heavy_a than_o the_o other_o as_o they_o be_v weigh_v in_o this_o balance_n of_o nature_n from_o what_o be_v say_v we_o see_v first_o that_o in_o water_n there_o be_v a_o pressure_n and_o a_o considerable_a weight_n this_o be_v evident_a from_o the_o rise_n of_o the_o mercury_n we_o see_v second_o that_o fluids_n counterpoise_n one_o another_o only_o according_a to_o altitude_n three_o that_o when_o a_o light_a fluid_n press_v up_o a_o heavy_a there_o be_v no_o more_o press_v up_o of_o it_o than_o be_v the_o just_a weight_n of_o the_o press_a fluid_n because_o the_o mercury_n e_o c_o be_v just_a the_o weight_n of_o the_o water_n that_o press_v upon_o x_o y_o o._n that_o be_v to_o say_v the_o part_n of_o the_o surface_n c_o be_v no_o more_o press_v with_o the_o mercury_n e_o c_o than_o the_o part_n x_o be_v press_v with_o the_o water_n l_o z_o x._o four_o if_o mercury_n be_v 28_o time_n heavy_a than_o water_n only_o three_o inch_n will_v be_v press_v up_o if_o it_o be_v but_o seven_o time_n heavy_a the_o altitude_n will_v be_v at_o saint_n 12_o inch_n above_o c._n five_o it_o be_v as_o easy_a for_o a_o large_a part_n of_o a_o surface_n to_o sustain_v a_o large_a pillar_n as_o it_o be_v for_o a_o narrow_a part_n to_o sustain_v a_o narrow_a pillar_n because_o a_o p_o sustain_v e_o c_o a_o as_o easy_o as_o b_o qui_fw-fr sustain_v g_o d_o b._n sixthly_a that_o in_o fluids_n there_o be_v a_o pondus_fw-la and_o a_o potentia_fw-la as_o be_v clear_a from_o the_o potentia_fw-la of_o a_o p_o that_o sustain_v the_o pondus_fw-la of_o e_o c_o a._n the_o water_n likewise_o that_o sustain_v have_v a_o potentia_fw-la and_o the_o mercury_n e_o c_o be_v the_o pondus_fw-la of_o it_o seven_o that_o there_o be_v always_o equality_n of_o weight_n between_o the_o pondus_fw-la and_o the_o potentia_fw-la so_o be_v the_o potentia_fw-la of_o a_o p_o equal_a to_o the_o pondus_fw-la e_o c_o a._n eighthly_a that_o the_o pondus_fw-la beget_v the_o potentia_fw-la so_o the_o weight_n of_o the_o water_n beget_v the_o potentia_fw-la that_n in_o a_o p._n for_o make_v this_o water_n deep_o and_o you_o augment_v the_o potentia_fw-la of_o a_o p._n if_o you_o subtract_v from_o it_o the_o potentia_fw-la of_o a_o p_o grow_v less_o by_o proportion_n or_o the_o weight_n of_o e_o c_o a_o may_v be_v say_v to_o beget_v the_o potentia_fw-la of_o a_o p._n to_o proceed_v a_o little_a further_o let_v we_o suppose_v the_o air_n h_o e_z to_o be_v remove_v in_o this_o case_n the_o mercury_n rise_v 29_o inch_n high_o than_o e_z or_o 35_o above_o c_o even_o as_o high_a as_o s._n in_o the_o narrow_a tub_n it_o will_v climb_v up_o to_o k_o if_o you_o take_v away_o the_o air_n i_o g._n this_o come_v to_o pass_v by_o virtue_n of_o the_o pressure_n of_o the_o atmosphere_n that_o rest_v upon_o l_o n._n from_o this_o we_o gather_v ninthly_a that_o there_o be_v a_o counterpoise_n between_o the_o air_n h_o e_o and_o the_o weight_n of_o the_o air_n that_o rest_v upon_o l_o n_o and_o that_o a_o slender_a pillar_n of_o air_n be_v able_a to_o counterpoise_v a_o thick_a for_o h_n e_z be_v far_o narrow_a than_o l_o n._n ten_o that_o the_o pressure_n of_o the_o air_n can_v be_v communicate_v through_o divers_a kind_n of_o fluid_n because_o the_o weight_n that_o rest_v upon_o l_o n_o be_v send_v down_o through_o the_o water_n l_o z_o x_o and_o down_o through_o the_o stagnant_a mercury_n and_o thrust_v up_o the_o liquor_n from_o a_o to_o saint_n 35_o inch_n eleven_o that_o a_o light_a fluid_n may_v be_v make_v to_o press_v with_o great_a burden_n than_o a_o fluid_a natural_o heavy_a because_o the_o weight_n of_o the_o air_n upon_o l_o n_o raises_z 29_o inch_n of_o mercury_n but_o the_o water_n raise_v only_o six_o we_o see_v twelfthly_a that_o fluids_n have_v a_o sphere_n of_o activity_n to_o which_o they_o be_v able_a to_o press_v up_o themselves_o or_o fluid_n of_o different_a kind_n because_o first_o the_o stagnant_a mercury_n can_v raise_v itself_o no_o high_o within_o the_o pipe_n than_o it_o be_v without_o next_o the_o 84_o inch_n of_o water_n can_v raise_v the_o mercury_n no_o high_o than_o e._n last_o the_o weight_n of_o the_o atmosphere_n can_v raise_v the_o mercury_n no_o high_o than_o saint_n 29_o inch_n above_o e._n for_o another_o trial_n take_v out_o from_o among_o the_o water_n the_o two_o pipe_n and_o stop_v close_o the_o two_o under_o orifice_n fill_v they_o with_o mercury_n to_o the_o brim_n then_o thrust_v they_o down_o as_o before_o and_o open_v the_o say_v two_o orifice_n while_o they_o be_v below_o the_o surface_n x_o in_n o_o and_o you_o will_v find_v the_o whole_a cylinder_n fall_n down_o from_o h_n to_o e_z and_o there_o halt_v and_o the_o whole_a cylinder_n in_o the_o narrow_a pipe_n fall_v down_o from_o i_o to_o g._n or_o if_o you_o please_v before_o this_o be_v do_v stop_v close_o the_o orifice_n h_n and_o the_o orifice_n i_o and_o you_o will_v find_v the_o mercury_n go_v no_o further_o down_o than_o saint_n by_o open_v the_o orifice_n a_o and_o no_o further_o down_o than_o k_o by_o open_v the_o orifice_n b._n this_o lead_v we_o to_o a_o clear_a discovery_n of_o the_o reason_n why_o the_o mercury_n subside_v and_o sink_v down_o from_o the_o top_n of_o the_o tub_n in_o the_o baroscope_n to_o the_o 29_o inch_n whatever_o the_o diameter_n of_o the_o pipe_n be_v and_o this_o let_v we_o see_v that_o the_o mercurial_a cylinder_n be_v suspend_v by_o the_o air_n after_o the_o same_o manner_n that_o the_o mercury_n e_o c_o be_v suspend_v after_o and_o that_o there_o be_v no_o more_o difficulty_n in_o the_o one_o than_o in_o the_o other_o experiment_n xvii_o figure_n 23_o 24._o this_o schematism_n represent_v a_o water_n 30_o fathom_n deep_a under_o the_o first_o surface_n a_o there_o be_v six_o imaginary_a as_o b_o c_o d_o e_o f_o g_o every_o one_o whereof_o be_v five_o fathom_v below_o another_o there_o be_v here_o likewise_o two_o glass_n each_o one_o 12_o inch_n high_a and_o 5_o inch_n broad_a like_a unto_o these_o wherein_o wine_n sack_n or_o brandy_n be_v preserve_v the_o glass_n g_o m_o have_v its_o orifice_n g_z upward_o the_o other_o glass_n be_v complete_o open_v below_o without_o a_o narrow_a orifice_n for_o make_v experiment_n take_v a_o long_a chord_n as_o long_o as_o the_o water_n be_v in_o deepness_n and_o knit_v the_o end_n of_o it_o round_o about_o the_o neck_n of_o the_o glass_n at_o g._n take_v another_o line_n of_o the_o same_o length_n and_o
air_n come_v out_o the_o reason_n be_v the_o same_o namely_o less_o pressure_n in_o e_z than_o in_o f_o therefore_o when_o the_o enclose_a air_n that_o have_v five_o degree_n of_o bensil_n come_v to_o e_o that_o have_v but_o four_o it_o must_v overcome_v and_o so_o long_o must_v it_o be_v victorious_a till_o by_o expand_v itself_o it_o be_v reduce_v to_o the_o bensil_n of_o four_o in_o pull_v up_o the_o glass_n from_o e_z to_z d_o more_z air_n yet_o break_v out_o because_o a_o surface_n of_o three_o degree_n of_o pressure_n be_v not_o able_a to_o resist_v four_o degree_n of_o bensil_n in_o pass_v from_o d_o to_z c_z more_z air_n come_v yet_o out_o for_o the_o same_o reason_n till_o in_o go_v up_o to_o the_o top_n where_o there_o be_v no_o pressure_n no_o more_o air_n break_v out_o it_o be_v to_o be_v observe_v first_o that_o the_o motion_n of_o the_o air_n up_o through_o the_o water_n be_v but_o slow_a the_o medium_n be_v thick_a and_o gross_a second_o that_o if_o the_o glass_n be_v pull_v up_o quick_o from_o one_o surface_n to_o another_o or_o contrariwise_o let_v down_o quick_o it_o present_o break_v in_o piece_n this_o come_v to_o pass_v through_o the_o strong_a bensil_n of_o the_o enclose_a air_n that_o must_v have_v time_n to_o expand_v itself_o otherwise_o it_o break_v out_o at_o the_o near_a for_o it_o be_v of_o six_o degree_n of_o bensil_n and_o come_v quick_o to_o a_o surface_n of_o five_o there_o happen_v a_o unequal_a pressure_n the_o side_n of_o the_o glass_n be_v thrust_v out_o with_o great_a force_n than_o they_o be_v thrust_v in_o with_o but_o if_o so_o be_v the_o glass_n move_v slow_o up_o the_o enclose_a air_n get_v time_n to_o thrust_v itself_o out_o by_o degree_n so_o that_o whatever_o surface_n the_o glass_n come_v to_o there_o be_v little_a difference_n between_o the_o pressure_n of_o the_o water_n and_o the_o bensil_n of_o the_o air._n the_o reason_n why_o the_o glass_n break_v in_o piece_n while_o it_o go_v quick_o down_o be_v likeways_o unequal_a pressure_n upon_o the_o side_n for_o in_o pass_v quick_o from_o a_o surface_n of_o five_o degree_n to_o a_o surface_n of_o six_o the_o side_n be_v press_v in_o with_o great_a force_n than_o they_o be_v press_v out_o with_o and_o the_o reason_n be_v because_o through_o the_o straitness_n of_o the_o hole_n g_o the_o water_n can_v win_v in_o soon_o enough_o to_o make_v as_o much_o pressure_n within_o as_o there_o be_v without_o it_o be_v to_o be_v observe_v three_o that_o if_o the_o orifice_n g_o be_v stop_v before_o that_o the_o glass_n be_v send_v down_o it_o will_v not_o go_v beyond_o three_o or_o four_o fathom_n when_o it_o shall_v be_v break_v in_o piece_n though_o the_o motion_n be_v never_o so_o slow_a and_o this_o come_v to_o pass_v through_o the_o strong_a pressure_n of_o the_o water_n four_o the_o strong_a the_o glass_n be_v in_o the_o side_n it_o go_v the_o further_o down_o without_o break_v therefore_o a_o round_a glass_n bottle_n will_v sink_v 20_o or_o 30_o fathom_n before_o that_o it_o be_v break_v with_o the_o pressure_n of_o the_o water_n if_o a_o vessel_n of_o iron_n be_v send_v down_o it_o ought_v to_o go_v much_o further_o a_o empty_a cask_n or_o hogshead_n will_v not_o sink_v beyond_o seven_o or_o eight_o fathom_n without_o break_v or_o burst_v yet_o a_o bladder_n full_a of_o wind_n knit_v about_o the_o neck_n with_o a_o packthread_n will_v go_v down_o 100_o fathom_n yea_o 1000_o without_o burst_v it_o may_v be_v here_o inquire_v what_o sort_n of_o proportion_n be_v keep_v by_o the_o unequal_a ingress_n of_o the_o water_n i_o answer_v it_o may_v be_v know_v after_o this_o manner_n let_v first_o down_o the_o glass_n one_o fathom_n and_o have_v pull_v it_o up_o again_o measure_v the_o deepness_n of_o the_o water_n in_o the_o bottom_n of_o it_o next_o have_v pour_v out_o that_o water_n let_v it_o down_o two_o fathom_n and_o pull_v it_o up_o measure_v the_o deepness_n which_o you_o will_v find_v more_o than_o afore_o do_v after_o this_o manner_n the_o three_o time_n and_o the_o four_o time_n till_o you_o come_v to_o the_o low_a fathom_n and_o you_o will_v find_v the_o true_a proportion_n from_o what_o be_v say_v we_o see_v first_o that_o in_o water_n there_o be_v a_o pressure_n because_o through_o the_o force_n and_o power_n of_o this_o water_n the_o 12_o inch_n of_o air_n that_o fill_v the_o glass_n be_v reduce_v to_o three_o second_o that_o this_o pressure_n grow_v as_o the_o water_n grow_v in_o deepness_n because_o there_o be_v more_o pressure_n in_o b_o than_o in_o a_o more_o in_o c_o than_z in_o b_o and_o io_n downward_o three_o that_o when_o air_n be_v compress_v by_o some_o extrinseck_n weight_n the_o bensil_n be_v intend_v and_o grow_v strong_a by_o unequal_a proportion_n as_o be_v clear_a from_o the_o unequal_a division_n 1_o 2_o 2_o 4_o 5_o 6._o four_o two_o fluid_n can_v cease_v from_o motion_n so_o long_o as_o the_o potentia_fw-la of_o the_o one_o be_v unequal_a to_o the_o pondu_n of_o the_o other_o this_o be_v evident_a from_o the_o water_n be_v creep_v in_o at_o g_o all_z the_o while_o the_o glass_n be_v in_o go_v down_o and_o from_o the_o air_n be_v come_v out_o all_o the_o while_n the_o glass_n be_v in_o come_v up_o five_o that_o no_o soon_o two_o fluids_n come_v to_o equality_n of_o weight_n but_o as_o soon_o the_o motion_n end_v because_o if_o the_o glass_n halt_v at_o d_o e_o or_o f_o in_o the_o go_n down_o upon_o which_o follow_v a_o counterpoise_n then_o do_v the_o creep_a in_o of_o the_o water_n cease_v six_o there_o may_v be_v as_o much_o pressure_n in_o a_o small_a quantity_n of_o a_o fluid_a as_o in_o the_o great_a because_o there_o be_v as_o much_o bensil_n in_o the_o small_a portion_n of_o air_n include_v between_o k_o and_o g_o as_o there_o be_v of_o pressure_n and_o weight_n in_o this_o whole_a water_n that_o be_v 30_o fathom_n deep_a seven_o that_o the_o pressure_n of_o a_o fluid_a be_v a_o thing_n real_o distinct_a from_o the_o natural_a weight_n this_o be_v evident_a from_o the_o pressure_n of_o the_o enclose_a air_n g_o k_n that_o be_v more_o and_o less_o as_o the_o pressure_n of_o the_o water_n k_o m_o be_v more_o and_o less_o but_o the_o natural_a weight_n be_v still_o the_o same_o see_v the_o same_o quantity_n remain_v eight_o one_o part_n of_o a_o fluid_a can_v be_v under_o pressure_n but_o the_o next_o adjacent_a must_v be_v under_o the_o same_o degree_n of_o pressure_n this_o be_v also_o clear_a because_o what_o ever_o degree_n of_o bensil_n the_o include_v air_n k_o g_o be_v under_z the_o water_n k_o m_o be_v under_o the_o same_o therefore_o when_o the_o one_o be_v under_o six_o as_o in_o the_o low_a fathom_n the_o other_o be_v under_o six_o likewise_o and_o when_o the_o one_o be_v under_o five_o degree_n of_o pressure_n as_o in_o the_o surface_n f_o the_o other_o be_v under_o as_o much_o nine_o bensil_n and_o pressure_n be_v equivalent_a to_o weight_n because_o the_o water_n k_o m_o be_v as_o much_o burden_v with_o the_o bensil_n of_o that_o small_a portion_n of_o air_n above_o it_o as_o if_o it_o have_v a_o pillar_n of_o water_n 30_o fathom_n high_a upon_o it_o ten_o that_o the_o pressure_n of_o fluids_n be_v most_o uniform_a and_o equal_a and_o that_o two_o fluid_n of_o different_a kind_n may_v press_v as_o uniform_o as_o if_o they_o be_v but_o one_o this_o be_v evident_a from_o the_o side_n of_o the_o glass_n that_o be_v not_o break_v in_o piece_n by_o the_o strong_a bensil_n of_o the_o enclose_a air_n and_o heavy_a pressure_n of_o the_o enclose_a water_n and_o this_o happen_v because_o the_o pressure_n without_o be_v as_o strong_a as_o the_o pressure_n within_o we_o see_v last_o that_o water_n do_v not_o weigh_v in_o water_n because_o when_o a_o man_n let_v down_o this_o glass_n by_o the_o chord_n to_o the_o low_a surface_n he_o find_v not_o the_o weight_n of_o the_o water_n k_o m_o that_o be_v within_o the_o glass_n but_o only_o the_o weight_n of_o the_o lead_n q._n it_o be_v certain_a he_o find_v not_o the_o weight_n of_o the_o water_n i_o h_n because_o it_o rest_v not_o upon_o the_o glass_n within_o but_o be_v sustain_v by_o '_o its_o own_o surface_n the_o mouth_n of_o the_o glass_n be_v downward_o and_o open_a when_o i_o say_v water_n do_v not_o weigh_v in_o water_n the_o meaning_n be_v not_o that_o water_n want_v weight_n or_o pressure_n in_o it_o but_o that_o this_o weight_n and_o pressure_n be_v not_o find_v as_o the_o weight_n and_o pressure_n of_o other_o body_n be_v find_v while_o they_o be_v weigh_v in_o water_n for_o example_n a_o piece_n of_o lead_n or_o gold_n hang_v in_o the_o water_n by_o a_o
string_n the_o other_o end_n be_v fasten_v to_o a_o balance_n in_o the_o air_n gravitat_n and_o weigh_v down_o the_o scale_n and_o the_o reason_n be_v because_o lead_v and_o gold_n be_v natural_o and_o specifical_o heavy_a than_o water_n but_o a_o piece_n of_o metal_n of_o the_o same_o specific_a weight_n with_o water_n or_o water_n itself_o can_v gravitat_fw-la in_fw-la water_n or_o weigh_v down_o the_o scale_n of_o a_o balance_n and_o the_o reason_n be_v because_o the_o surface_n of_o water_n upon_o which_o they_o rest_v bear_v they_o up_o with_o as_o great_a weight_n and_o force_n as_o they_o press_v down_o with_o if_o it_o be_v say_v that_o the_o water_n k_o m_o rest_v upon_o the_o bottom_n of_o the_o glass_n within_o and_o therefore_o if_o the_o man_n above_o find_v the_o weight_n of_o the_o glass_n he_o must_v find_v the_o weight_n of_o the_o water_n within_o it_o i_o answer_v the_o consequence_n be_v bad_a because_o the_o weight_n of_o the_o water_n within_o be_v sustain_v and_o counterpoise_v by_o the_o weight_n of_o the_o water_n without_o whereupon_o the_o bottom_n of_o the_o glass_n rest_v that_o be_v to_o say_v as_o there_o be_v a_o pillar_n of_o water_n k_o m_o within_o the_o glass_n that_o press_v down_o the_o bottom_n so_o there_o be_v a_o pillar_n of_o water_n without_o the_o glass_n whereupon_o the_o bottom_n of_o the_o glass_n rest_v and_o which_o bear_v up_o both_o but_o the_o great_a difficulty_n be_v this_o the_o further_a down_o the_o glass_n go_v it_o grow_v the_o heavy_a because_o of_o more_o and_o more_o water_n that_o creep_v in_o at_o g._n now_o it_o be_v certain_a the_o weight_n q_n grow_v not_o heavy_a therefore_o it_o must_v be_v the_o water_n within_o the_o glass_n that_o make_v the_o increase_n of_o the_o weight_n and_o therefore_o water_n must_v still_o weigh_v in_o water_n if_o this_o argument_n have_v any_o strength_n in_o it_o it_o will_v prove_v the_o weight_n of_o the_o water_n i_o h_n to_o gravitat_fw-la and_o weigh_v likewise_o because_o the_o further_a down_o this_o glass_n go_v it_o grow_v the_o heavy_a because_o of_o more_o and_o more_o water_n that_o creep_v up_o from_o h_n to_o i._o now_o it_o be_v certain_a the_o weight_n of_o lead_n b_o grow_v not_o heavy_a behold_v the_o difficulty_n be_v the_o same_o in_o both_o and_o yet_o it_o be_v rashness_n to_o affirm_v the_o water_n i_o h_n to_o be_v find_v by_o a_o man_n hand_n when_o he_o pull_v up_o the_o glass_n with_o a_o string_n see_v it_o be_v sustain_v by_o its_o own_o surface_n and_o not_o by_o any_o part_n of_o the_o glass_n though_o this_o may_v suffice_v for_o a_o answer_n yet_o because_o the_o contrary_n be_v mantain_v by_o some_o and_o that_o with_o a_o new_a experiment_n to_o prove_v it_o i_o shall_v be_v at_o some_o more_o pain_n to_o vindicat_fw-la the_o truth_n of_o what_o i_o have_v say_v this_o new_a experiment_n to_o prove_v that_o water_n weigh_v in_o water_n i_o find_v in_o a_o philosophical_a transaction_n of_o august_n 16._o anno_fw-la 1669._o numb_a 50_o the_o invention_n whereof_o be_v attribute_v by_o the_o publisher_n to_o that_o honourable_a and_o worthy_a person_n mr._n boyl_n who_o conclusion_n and_o trial_n i_o never_o much_o call_v in_o question_n but_o find_v this_o opposite_a and_o contrary_a to_o what_o i_o have_v demonstrate_v i_o shall_v crave_v liberty_n to_o say_v amicus_fw-la socrates_n amicus_fw-la plato_n sed_fw-la magis_fw-la amica_fw-la veritas_fw-la and_o shall_v therefore_o examine_v it_o as_o brief_o as_o may_v be_v the_o word_n of_o the_o publisher_n be_v as_o follow_v the_o author_n of_o this_o invention_n be_v the_o noble_a robert_n boyl_n who_o be_v please_v to_o comply_v with_o our_o desire_n of_o communicate_v it_o in_o english_a to_o the_o curious_a in_o england_n as_o by_o insert_v the_o same_o in_o the_o latin_a translation_n of_o his_o hydrostatical_a paradox_n he_o have_v gratify_v the_o ingenious_a abroad_o and_o it_o will_v doubtless_o be_v the_o more_o welcome_a for_o as_o much_o as_o no_o body_n we_o know_v of_o have_v so_o much_o as_o attempt_v to_o determine_v how_o much_o water_n may_v weigh_v in_o water_n and_o possible_o if_o such_o a_o problem_n have_v be_v propose_v it_o will_v have_v be_v judge_v impracticable_a the_o method_n or_o expedient_a he_o make_v use_v of_o to_o perform_v it_o as_o near_o as_o he_o can_v may_v easy_o be_v learn_v by_o the_o ensue_a account_n of_o a_o trial_n or_o two_o he_o make_v for_o that_o purpose_n which_o among_o his_o note_n he_o cause_v to_o be_v register_v in_o the_o follow_a word_n a_o glass-bubble_n of_o about_o the_o bigness_n of_o a_o pullet_n egg_n be_v purposely_o blow_v at_o the_o flame_n of_o a_o lamp_n with_o a_o somewhat_o long_o stem_v turn_v up_o at_o the_o end_n that_o it_o may_v the_o more_o convenient_o be_v break_v off_o this_o bubble_n be_v well_o heat_v to_o rarify_v the_o air_n and_o thereby_o drive_v out_o a_o good_a part_n of_o it_o be_v nimble_o seal_v at_o the_o end_n and_o by_o the_o help_n of_o the_o figure_n of_o the_o stem_n be_v by_o a_o convenient_a weight_n of_o lead_n depress_v under_o water_n the_o lead_n and_o glass_n be_v tie_v by_o a_o string_n to_o a_o scale_n of_o a_o good_a balance_n in_o who_o other_o there_o be_v put_v so_o much_o weight_n as_o suffice_v to_o counterpoise_v the_o bubble_n as_o it_o hang_v free_o in_o the_o midst_n of_o the_o water_n then_o with_o a_o long_a iron_n forceps_fw-la i_o careful_o break_v off_o the_o seal_a end_n of_o the_o bubble_n under_o water_n so_o as_o no_o bubble_n of_o air_n appear_v to_o emerge_n or_o escape_n through_o the_o water_n but_o the_o liquor_n by_o the_o weight_n of_o the_o atmosphere_n spring_v into_o the_o unreplenished_a part_n of_o the_o glass-bubble_n and_o fill_v the_o whole_a cavity_n about_o half_a full_a and_o present_o as_o i_o foretell_v the_o bubble_n subside_v and_o make_v the_o scale_n it_o be_v fasten_v to_o preponderate_a so_o much_o that_o there_o need_v 4_o drachm_n and_o 38_o grain_n to_o reduce_v the_o balance_n to_o a_o equilibrium_n then_o take_v out_o the_o bubble_n with_o the_o water_n in_o it_o we_o do_v by_o the_o help_n of_o a_o flame_n of_o a_o candle_n wary_o apply_v drive_v out_o the_o water_n which_o otherwise_o be_v not_o easy_o exclude_v at_o a_o very_a narrow_a stem_n into_o a_o glass_n counterpoise_v before_o and_o we_o find_v it_o as_o we_o expect_v to_o weigh_v about_o four_o drachm_n and_o 30_o grain_n beside_o some_o little_a that_o remain_v in_o the_o egg_n and_o some_o small_a matter_n that_o may_v have_v be_v rarify_v into_o vapour_n which_o add_v to_o the_o piece_n of_o glass_n that_o be_v break_v off_o under_o water_n and_o lose_v there_o may_v very_o well_o amount_v to_o 7_o or_o 8_o grain_n by_o which_o it_o appear_v not_o only_o that_o water_n have_v some_o weight_n in_o water_n but_o that_o it_o weigh_v very_o near_o or_o altogether_o as_o much_o in_o water_n as_o the_o self_n same_o portion_n of_o liquor_n will_v weigh_v in_o the_o air._n the_o same_o day_n we_o repeat_v the_o experiment_n with_o another_o seal_a bubble_n large_a than_o the_o former_a be_v as_o big_a as_o a_o great_a hens-egg_n and_o have_v break_v this_o under_o water_n it_o grow_v heavy_a by_o 7._o drachm_n and_o 34_o grain_n and_o have_v take_v out_o the_o bubble_n and_o drive_v out_o the_o water_n into_o a_o counter_a poise_v glass_n we_o find_v the_o transvasated_a liquor_n to_o amount_v to_o the_o same_o weight_n abate_v 6_o or_o 7_o grain_n which_o it_o may_v well_o have_v lose_v upon_o such_o account_n as_o have_v be_v new_o mention_v thus_o he_o figure_n 24._o the_o design_n then_o of_o this_o experiment_n be_v to_o prove_v that_o water_n weigh_v in_o water_n but_o it_o seem_v there_o be_v here_o a_o very_a great_a mistake_n which_o i_o shall_v make_v out_o after_o this_o manner_n for_o which_o cause_n let_v this_o schematism_n 24_o represent_v the_o experiment_n already_o describe_v the_o â—lass-bubble_n than_o be_v e_o p_o f_o r._n the_o stem_n be_v h_n c_o the_o weight_n that_o sink_v the_o glass_n be_v b._n the_o surface_n of_o water_n under_o which_o it_o be_v drown_v be_v a_o d._n the_o balance_n to_o which_o the_o glass_n be_v knit_v by_o a_o string_n be_v n_o o._n and_o last_o e_o f_o r_o be_v the_o water_n that_o come_v in_o and_o fill_v the_o half_a of_o the_o bubble_n now_o i_o say_v it_o be_v not_o the_o weight_n of_o the_o water_n e_o f_o r_o that_o turn_v the_o scale_n above_o and_o make_v a_o alteration_n in_o the_o balance_n but_o '_o its_o only_a the_o weight_n of_o the_o lead_n b_o that_o do_v it_o for_o evince_v this_o consider_v that_o all_o heavy_a body_n be_v either_o light_a in_o specie_fw-la than_o water_n
weigh_v by_o a_o piece_n of_o lead_n or_o stone_n in_o a_o artificial_a balance_n for_o know_v how_o many_o ounce_n or_o pound_n it_o be_v of_o as_o if_o a_o man_n shall_v endeavour_v to_o weigh_v the_o water_n e_o f_o r_o by_o help_n of_o the_o balance_n above_o which_o in_o effect_n be_v impossible_a experiment_n xviii_o figure_n 25._o make_v a_o wooden_a ark_n after_o this_o follow_a manner_n the_o plank_n must_v be_v of_o oak_n a_o inch_n thick_a the_o height_n 40_o inch_n the_o breadth_n 36._o closs_n on_o all_o side_n and_o above_o and_o open_v below_o and_o because_o the_o form_n be_v foursquare_a there_o must_v be_v four_o standart_v of_o timber_n in_o each_o corner_n one_o to_o which_o the_o plank_n must_v be_v nail_v four_o likewise_o upon_o the_o top_n cross_v the_o other_o four_o at_o right_a angle_n to_o which_o the_o cover_n must_v be_v join_v the_o side_n must_v be_v plain_v and_o the_o edge_n both_o plain_v and_o gripe_v in_o all_o the_o part_n that_o the_o joyning_n may_v be_v close_o upon_o the_o top_n fasten_v a_o strong_a iron_n ring_n as_o at_o n_o through_o which_o must_v be_v fasten_v a_o rope_n of_o so_o many_o foot_n or_o fathom_n and_o because_o the_o use_n of_o this_o engine_n be_v for_o dive_v under_o the_o water_n it_o must_v therefore_o be_v all_o cover_v over_o with_o pitch_n within_o and_o without_o especial_o in_o the_o couple_n and_o because_o this_o instrument_n can_v sink_v of_o its_o own_o accord_n it_o must_v have_v a_o great_a weight_n of_o lead_n append_v to_o it_o for_o that_o cause_n whereupon_o the_o divers_a foot_n must_v stand_v while_o he_o be_v in_o go_v down_o the_o precise_a quantity_n and_o weight_n of_o it_o can_v be_v determine_v because_o it_o depend_v upon_o the_o quantity_n of_o the_o ark_n which_o if_o large_a require_v a_o great_a weight_n if_o of_o a_o lesser_a size_n require_v a_o lesser_a weight_n but_o whatever_o the_o dimension_n of_o the_o ark_n may_v be_v the_o weight_n of_o the_o leaden-foot-stool_n 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sense_n and_o so_o be_v in_o danger_n of_o fall_v out_o of_o the_o ark_n or_o if_o his_o foot_n shall_v slide_v off_o the_o footstool_n and_o his_o hand_n fail_v he_o too_o a_o chord_n knit_v to_o one_o of_o those_o and_o fasten_v about_o his_o waist_n or_o middle_a may_v bring_v he_o up_o though_o he_o be_v dead_a then_o it_o be_v far_o easy_a to_o cut_v out_o a_o window_n or_o two_o in_o the_o side_n of_o it_o not_o very_o large_a but_o little_a as_o k_o and_o i_o whereby_o they_o be_v cover_v with_o glass_n a_o man_n may_v see_v at_o a_o distance_n what_o be_v upon_o the_o right_a hand_n and_o what_o be_v upon_o the_o left_a and_o what_o be_v before_o this_o device_n be_v of_o excellent_a use_n for_o through_o the_o want_n of_o it_o the_o diver_n see_v no_o more_o but_o what_o be_v just_a below_o he_o which_o sometime_o when_o he_o be_v near_o the_o ground_n will_v not_o exceed_v the_o compass_n of_o a_o large_a milâ—wheel_n but_o if_o so_o be_v three_o hole_n be_v cut_v through_o one_o on_o every_o hand_n and_o one_o before_o he_o may_v see_v as_o much_o bound_n and_o all_o thing_n in_o it_o as_o if_o he_o be_v not_o enclose_v and_o environ_v with_o a_o cover_n a_o little_a schelf_n likewise_o may_v be_v fix_v upon_o the_o one_o side_n or_o the_o other_o for_o hold_v a_o compass_n with_o a_o magnetical_a needle_n for_o know_v how_o such_o and_o such_o a_o thing_n lie_v in_o the_o ground_n of_o the_o sea_n in_o one_o of_o the_o corner_n may_v hang_v a_o little_a bottle_n with_o some_o excellent_a spirit_n for_o refresh_v the_o stomach_n under_o water_n many_o more_o advantage_n i_o may_v name_v this_o engine_n be_v of_o timber_n but_o shall_v forbear_v leave_v the_o collection_n of_o they_o to_o the_o ingenious_a reader_n and_o proceed_v to_o answer_v some_o objection_n that_o may_v be_v make_v against_o it_o first_o if_o this_o engine_n be_v make_v of_o wood_n it_o will_v not_o sink_v so_o easy_o as_o be_v make_v of_o lead_n i_o answer_v this_o difficulty_n be_v soon_o overcome_v namely_o by_o make_v the_o footstool_n the_o heavy_a therefore_o how_o light_n soever_o it_o be_v a_o weight_n may_v be_v find_v to_o counterpoise_v it_o in_o the_o water_n if_o it_o be_v judge_v too_o light_a in_o timber_n it_o may_v be_v line_v with_o lead_n especial_o without_o second_o if_o it_o be_v of_o wood_n there_o must_v be_v couple_n and_o joyning_n in_o it_o and_o so_o rift_n and_o leak_n in_o it_o through_o which_o the_o water_n may_v come_v i_o answer_v there_o be_v less_o difficulty_n here_o than_o in_o the_o former_a because_o the_o joint_n may_v be_v make_v so_o close_o in_o all_o the_o part_n and_o may_v be_v so_o cover_v over_o with_o pitch_n or_o with_o some_o such_o like_a matter_n that_o it_o may_v defy_v either_o water_n to_o come_v in_o or_o air_n to_o go_v out_o three_o if_o it_o be_v make_v of_o wood_n it_o will_v be_v in_o hazard_n of_o break_v by_o the_o force_n of_o the_o water_n for_o oft_o time_n be_v find_v that_o the_o strong_a hogshead_n will_v burst_v asunder_o by_o the_o pressure_n of_o it_o if_o they_o go_v but_o down_o 7_o or_o 8_o fathom_n i_o answer_v this_o objection_n flow_v from_o the_o ignorance_n of_o the_o nature_n of_o fluid_a body_n if_o so_o be_v then_o that_o a_o man_n know_v that_o the_o pressure_n of_o water_n be_v uniform_a most_o equal_a and_o press_v upon_o all_o the_o part_n of_o a_o body_n within_o it_o alike_o no_o such_o scruple_n will_v occur_v i_o say_v then_o the_o ark_n though_o no_o thick_a in_o the_o side_n than_o a_o thin_a sawen_v dale_n will_v go_v down_o in_o spite_n of_o all_o the_o
pressure_n that_o be_v in_o the_o water_n not_o only_o 10_o but_o 20_o or_o 30_o fathom_n without_o all_o hazard_n and_o the_o reason_n be_v because_o what_o pressure_n soever_o be_v without_o to_o press_v in_o the_o side_n the_o same_o degree_n of_o pressure_n be_v within_o to_o press_v they_o out_o by_o this_o mean_n there_o be_v not_o one_o part_n of_o the_o water_n how_o deep_a soever_o to_o which_o the_o ark_n may_v come_v down_o but_o there_o will_v be_v find_v as_o much_o force_n in_o the_o air_n within_o as_o will_v counterbalance_v the_o whole_a weight_n without_o as_o will_v be_v infallible_o demonstrate_v afterward_o this_o answer_v a_o four_o objection_n namely_o if_o hole_n be_v cut_v out_o in_o the_o side_n of_o the_o ark_n in_o stead_n of_o window_n the_o force_n of_o the_o water_n will_v break_v the_o glass_n in_o piece_n that_o cover_v they_o there_o be_v here_o no_o hazard_n though_o the_o say_v window_n be_v 12_o inch_n in_o diameter_n but_o it_o be_v not_o needful_a they_o be_v so_o large_a it_o be_v sufficient_a if_o they_o be_v 2_o inch_n wide_a for_o a_o man_n eye_n near_o to_o a_o hole_n 2_o inch_n wide_a will_v see_v a_o great_a way_n about_o he_o there_o be_v a_o necessity_n the_o glass_n be_v join_v in_o with_o cement_n that_o water_n may_v not_o have_v access_n to_o come_v in_o or_o air_n to_o go_v out_o in_o such_o a_o case_n there_o be_v no_o hazard_n that_o the_o pressure_n of_o the_o water_n will_v break_v through_o the_o window_n or_o break_v the_o glass_n because_o the_o pressure_n of_o the_o air_n within_o be_v of_o the_o same_o force_n with_o the_o strength_n of_o the_o water_n without_o the_o glass_n be_v keep_v entire_a it_o may_v be_v inquire_v what_o hazard_n will_v follow_v upon_o supposition_n a_o small_a hole_n be_v pierce_v in_o the_o head_n of_o the_o ark_n above_o when_o it_o be_v go_v down_o i_o answer_v there_o be_v not_o so_o much_o hazard_v as_o a_o man_n will_v think_v provide_v the_o hole_n be_v not_o wide_a but_o 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degree_n of_o weight_n the_o water_n press_v up_o the_o air_n with_o the_o same_o degree_n of_o force_n and_o power_n do_v the_o air_n press_v down_o the_o water_n if_o this_o be_v not_o it_o will_v be_v impossible_a for_o a_o man_n to_o go_v down_o because_o of_o pain_n for_o when_o one_o part_n of_o a_o man_n body_n be_v less_o press_v than_o another_o there_o arise_v a_o considerable_a pain_n which_o sometime_o be_v intolerable_a as_o be_v evident_a from_o the_o application_n of_o ventoso-glass_n this_o equality_n of_o weight_n be_v the_o true_a reason_n why_o respiration_n be_v so_o easy_a yet_o it_o be_v to_o be_v observe_v that_o a_o man_n can_v breathe_v so_o easy_o in_o the_o ark_n under_o the_o water_n as_o above_o in_o the_o air_n not_o because_o there_o be_v any_o inequality_n between_o the_o weight_n of_o the_o water_n and_o the_o force_n of_o the_o air_n but_o only_o because_o the_o quantity_n of_o it_o be_v little_a for_o when_o a_o man_n suck_v in_o as_o much_o air_n 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and_o a_o half_a of_o air_n n_o g_o be_v as_o heavy_a as_o the_o 25_o foot_n and_o a_o half_a of_o the_o water_n that_o be_v go_v this_o make_v it_o evident_a also_o that_o when_o the_o pipe_n be_v half_a full_a of_o water_n as_o e_o k_o the_o air_n i_o g_o have_v the_o weight_n of_o 952_o pound_n because_o e_z be_v in_o itself_o 1904_o but_o be_v burden_v with_o e_o k_o 952_o it_o can_v make_v the_o top_n of_o the_o water_n k_o press_v upon_o i_o with_o more_o weight_n than_o 952_o and_o therefore_o by_o the_o 20_o theorem_fw-la the_o air_n g_o i_o must_v weigh_v 952_o likewise_o i_o affirm_v eighthly_a that_o when_o the_o pipe_n be_v full_a of_o water_n from_o e_z to_z g_z if_o a_o man_n poise_v it_o in_o his_o hand_n he_o do_v not_o find_v the_o weight_n of_o the_o water_n e_o g._n and_o the_o reason_n be_v because_o it_o be_v sustain_v by_o the_o part_n of_o the_o surface_n e._n but_o if_o the_o air_n e_o sustain_v it_o my_o hand_n can_v sustain_v it_o i_o find_v then_o only_o the_o weight_n of_o the_o tub_n but_o not_o the_o weight_n of_o the_o water_n within_o it_o i_o say_v ninthly_a that_o when_o i_o poise_v the_o say_a tub_n i_o find_v the_o whole_a weight_n of_o the_o pillar_n of_o air_n l_o m_o which_o be_v exact_o 1904_o pound_n i_o prove_v it_o thus_o the_o pondus_fw-la of_o a_o fluid_a be_v then_o only_o find_v when_o there_o be_v not_o a_o potentia_fw-la to_o counterpoise_v it_o or_o at_o least_o when_o the_o potentia_fw-la be_v inferior_a to_o the_o pondus_fw-la but_o there_o be_v here_o no_o potentia_fw-la counterpoise_v the_o pondus_fw-la of_o the_o air_n l_o m._n therefore_o i_o must_v find_v the_o weight_n of_o it_o when_o i_o lift_v up_o the_o tub._n the_o major_a proposition_n be_v clear_a from_o the_o ten_o theorem_fw-la it_o be_v evident_a also_o from_o common_a experience_n for_o while_o a_o balance_n be_v hang_v upon_o a_o nail_n with_o six_o pound_n in_o the_o one_o scale_n and_o nothing_o in_o the_o other_o you_o will_v find_v the_o whole_a burden_n if_o you_o press_v up_o that_o one_o scale_n with_o the_o palm_n of_o your_o hand_n but_o if_o so_o be_v there_o be_v six_o pound_n in_o the_o opposite_a scale_n you_o will_v not_o find_v the_o first_o six_o and_o the_o reason_n be_v because_o it_o be_v in_o equilibrio_n with_o other_o six_o it_o be_v just_a so_o here_o i_o must_v find_v the_o weight_n of_o the_o air_n l_o m_o while_n i_o poise_v the_o tub_n because_o it_o want_v a_o weight_n to_o counterbalance_v it_o i_o prove_v the_o minor_a proposition_n thus_o if_o any_o thing_n counterbalance_v the_o air_n l_o m_o it_o must_v either_o be_v the_o air_n below_o namely_o the_o part_n e_o or_o the_o water_n e_o g_o but_o neither_o of_o the_o twain_o can_v do_v it_o not_o the_o air_n e_o because_o it_o have_v as_o great_a a_o burden_n upon_o it_o as_o it_o be_v able_a to_o support_v namely_o the_o water_n e_o g_o that_o weigh_v 1904_o pound_n and_o for_o this_o cause_n not_o the_o water_n itself_o see_v all_o the_o 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other_o for_o it_o be_v a_o certain_a and_o infallible_a rule_n in_o the_o hydrostaticks_n that_o water_n will_v rise_v as_o high_a in_o this_o place_n as_o the_o height_n of_o the_o place_n be_v from_o whence_o it_o come_v even_o though_o the_o wind_n and_o turn_n of_o the_o lead-conduit_n underground_o be_v as_o a_o labyrinth_n and_o though_o this_o place_n be_v not_o only_o 1000_o but_o 5000_o pace_n distant_a from_o the_o other_o it_o be_v to_o be_v observe_v that_o if_o the_o mouth_n of_o the_o conduit_n here_o be_v exact_o as_o high_a as_o the_o other_o end_n at_o the_o fountain_n the_o water_n stand_v still_o and_o the_o great_a the_o difference_n be_v the_o water_n flow_v out_o with_o the_o great_a force_n by_o the_o help_n of_o such_o conduit_n it_o be_v easy_a to_o convey_v water_n to_o a_o city_n many_o mile_n such_o pipe_n be_v ordinary_o make_v of_o lead_n but_o for_o save_v expense_n they_o may_v be_v make_v of_o timber_n or_o clay_n well_o burn_v in_o a_o oven_n a_o 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he_o begin_v to_o stagger_v and_o his_o foot_n fail_v he_o he_o fall_v down_o as_o one_o overtake_v with_o the_o epilepsy_n and_o in_o go_v down_o to_o the_o bottom_n his_o eye_n turn_v in_o his_o head_n they_o appear_v very_o shine_v and_o clear_a like_o two_o large_a bright_a diamond_n fear_v that_o the_o damp_n shall_v have_v kill_v he_o out_o of_o hand_n he_o be_v instant_o pull_v up_o from_o the_o bottom_n where_o he_o have_v not_o tarry_v 15_o second_n of_o time_n and_o when_o the_o bucket_n have_v come_v to_o the_o mouth_n of_o the_o sink_n he_o be_v pull_v out_o and_o lay_v upon_o the_o ground_n to_o get_v fresh_a air._n when_o he_o have_v lie_v a_o while_n as_o dead_a he_o begin_v at_o last_o to_o gape_v and_o gasp_n and_o makesome_a respiration_n as_o if_o he_o have_v be_v rather_o expire_a than_o recover_v next_o he_o begin_v to_o stir_v and_o move_v his_o foot_n and_o after_o to_o raise_v himself_o upon_o his_o knee_n his_o head_n stagger_v and_o waver_v from_o side_n to_o 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by_o the_o agitation_n of_o a_o man_n body_n that_o sometime_o abundance_n of_o air_n be_v see_v to_o ascend_v up_o through_o the_o pipe_n which_o in_o effect_n make_v the_o cylinder_n short_a than_o it_o ought_v to_o be_v but_o if_o so_o be_v the_o end_n of_o the_o pipe_n be_v immerge_v among_o quicksilver_n contain_v in_o a_o glass_n with_o a_o narrow_a orifice_n so_o that_o it_o may_v be_v stop_v complete_o you_o will_v find_v no_o reciprocation_n at_o all_o and_o to_o make_v all_o thing_n the_o more_o sure_a the_o glass_n may_v be_v fill_v up_o either_o with_o mercury_n or_o with_o water_n above_o the_o mercury_n by_o which_o mean_v the_o cylinder_n in_o the_o downcoming_a or_o in_o the_o up-going_a shall_v remain_v immovable_a beside_o the_o stop_n of_o the_o orifice_n of_o the_o say_a glass_n you_o may_v have_v a_o wide_a vessel_n that_o may_v receive_v the_o same_o glass_n into_o it_o and_o it_o be_v full_a of_o water_n may_v so_o cover_v the_o seal_a orifice_n that_o there_o shall_v be_v no_o hazard_n of_o any_o air_n come_v in_o or_o this_o experiment_n may_v be_v first_o try_v at_o the_o root_n of_o the_o hill_n and_o have_v stop_v complete_o the_o mouth_n of_o the_o vessel_n the_o whole_a engine_n may_v be_v carry_v up_o to_o the_o top_n where_o you_o will_v find_v the_o mercury_n subside_o and_o fall_v down_o so_o much_o namely_o after_o the_o say_a orifice_n be_v open_v for_o as_o the_o stop_n of_o the_o orifice_n at_o the_o root_n of_o the_o hill_n be_v the_o cause_n why_o that_o same_o degree_n of_o pressure_n remain_v in_o the_o stagnant_a liquor_n so_o the_o open_n of_o it_o upon_o the_o top_n of_o the_o hill_n be_v the_o cause_n why_o it_o become_v less_o this_o experiment_n let_v we_o see_v that_o the_o pressure_n of_o the_o air_n seem_v to_o be_v as_o the_o pressure_n of_o the_o water_n namely_o the_o further_a down_o the_o great_a and_o the_o further_o up_o the_o less_o and_o therefore_o as_o by_o come_v up_o to_o the_o top_n of_o the_o 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the_o sky_n red_a but_o clear_a also_o and_o by_o the_o help_n of_o the_o pendulum_n clock_n i_o have_v observe_v his_o body_n to_o be_v long_o in_o set_v than_o it_o ought_v by_o eight_o minute_n and_o sometime_o by_o ten_o and_o his_o diameter_n long_o in_o go_v out_o of_o sight_n than_o it_o ought_v by_o two_o and_o sometime_o by_o three_o minute_n the_o reason_n of_o these_o phenomena_n must_v be_v the_o refraction_n unquestionable_o observation_n vi._n upon_o saturday_n evening_n the_o 30_o of_o july_n 1670_o and_o the_o night_n follow_v till_o about_o two_o a_o clock_n in_o the_o sabbath_n morning_n there_o fall_v out_o a_o considerable_a rain_n with_o great_a thunder_n and_o many_o lightning_n about_o sunset_n the_o convocation_n of_o black_a cloud_n appear_v first_o towards_o the_o horizon_n in_o the_o south-west_n with_o several_a lightning_n and_o the_o wind_n blow_v from_o that_o point_n carry_v the_o cloud_n and_o rain_n over_o mid_a and_o east-lothian_n towards_o the_o firth_n and_o sea-coast_n about_o 9_o a_o clock_n the_o whole_a heaven_n almost_o be_v cover_v with_o dark_a cloud_n yet_o the_o rain_n be_v not_o very_o great_a neither_o be_v the_o thunder_n clap_v frequent_a but_o every_o five_o or_o six_o second_v of_o time_n a_o large_a and_o great_a lightning_n break_v out_o but_o before_o the_o thunder_n crack_n be_v hear_v which_o happen_v every_o four_o or_o five_o minute_n the_o lightning_n be_v so_o terrible_a for_o greatness_n and_o brightness_n that_o it_o may_v have_v breed_v astonishment_n and_o because_o the_o night_n be_v very_o dark_a and_o the_o lightning_n very_o splendid_a a_o man_n may_v have_v perceive_v house_n and_o cornfield_n at_o a_o great_a distance_n and_o if_o any_o have_v resolve_v to_o catch_v it_o in_o the_o break_n out_o it_o do_v so_o dazzle_v the_o eye_n that_o for_o half_a a_o minute_n he_o be_v not_o able_a to_o see_v any_o thing_n about_o he_o sometime_o the_o lightning_n that_o go_v before_o the_o thunder_n break_v forth_o from_o the_o cloud_n like_o a_o long_a spout_n of_o fire_n or_o rather_o like_o a_o long_a flame_n raise_v high_a with_o a_o smith_n bellows_o but_o do_v not_o continue_v long_o in_o sight_n such_o a_o one_o above_o the_o firth_n be_v see_v to_o spout_v downward_o upon_o the_o sea_n sometime_o there_o appear_v from_o the_o one_o end_n of_o the_o cloud_n to_o the_o other_o a_o hiatus_fw-la or_o wide_a open_n all_o full_a of_o fire_n in_o form_n of_o a_o long_a furrow_n or_o branch_n of_o a_o river_n not_o straight_o but_o crooked_a i_o suppose_v the_o breadth_n of_o it_o in_o itself_o will_v have_v be_v twenty_o pace_n and_o more_o and_o the_o length_n of_o it_o five_o or_o six_o hundred_o pace_n the_o duration_n of_o it_o will_v have_v be_v about_o a_o second_o of_o time_n sometime_o a_o man_n may_v have_v perceive_v the_o nether_a side_n of_o the_o cloud_n before_o the_o crack_n come_v all_o speckled_a with_o stream_n of_o fire_n here_o and_o there_o like_o the_o side_n of_o a_o hill_n where_o moorburn_a be_v which_o break_v forth_o into_o a_o lightning_n but_o there_o be_v one_o after_o which_o follow_v a_o terrible_a thunder_n crack_v which_o far_o exceed_v all_o the_o rest_n for_o quantity_n and_o splendour_n it_o break_v out_o from_o the_o cloud_n be_v shoot_v from_o north_n to_o south_n in_o form_n of_o fire_n from_o a_o great_a cannon_n but_o in_o so_o great_a quantity_n as_o if_o a_o gun_n ten_o foot_n wide_a with_o 500_o pound_n weight_n of_o powder_n in_o it_o have_v be_v fire_v and_o sure_o the_o lightning_n behove_v to_o be_v far_o great_a in_o itself_o see_v it_o appear_v so_o great_a at_o so_o great_a a_o distance_n it_o do_v not_o evanish_v in_o a_o instant_n like_o the_o fire_n of_o a_o gun_n but_o continue_v about_o a_o second_o and_o a_o half_a by_o reason_n it_o seem_v that_o it_o can_v not_o break_v out_o all_o at_o once_o this_o do_v so_o dazzle_v the_o sight_n that_o for_o half_a a_o minute_n almost_o nothing_o be_v see_v but_o like_o a_o white_a mist_n fly_v before_o the_o eye_n the_o whole_a country_n about_o be_v see_v distinct_o all_o these_o great_a lightning_n be_v see_v a_o considerable_a time_n before_o the_o crack_n be_v hear_v sometime_o 30_o second_n number_v by_o the_o pendulum_n clock_n interveened_a namely_o when_o the_o thunder_n be_v at_o a_o distance_n about_z 7_o or_o 8_o mile_n sometime_o 15_o or_o 16_o only_o interveen_v but_o when_o the_o thunder_n be_v just_a above_o our_o head_n no_o more_o pass_v than_o 7_o or_o 8_o which_o seem_v to_o demonstrat_fw-la that_o these_o thick_a black_a cloud_n out_o of_o which_o the_o thunder_n break_v be_v not_o a_o scottish_a mile_n from_o the_o earth_n when_o they_o be_v direct_o above_o we_o it_o be_v observable_a that_o in_o all_o lightning_n and_o thundering_n there_o be_v no_o smoke_n to_o be_v see_v which_o seem_v to_o evince_v that_o the_o matter_n whereof_o they_o be_v generate_v must_v be_v most_o pure_a and_o subtle_a who_o know_v but_o this_o country_n that_o abound_v with_o coal_n may_v occasion_v more_o thunder_n and_o lightning_n than_o other_o place_n namely_o by_o send_v up_o sulphurous_a exhalation_n to_o the_o middle_a region_n of_o the_o air_n wherewith_o the_o coal-mine_n abound_v observation_n vii_o this_o be_v a_o method_n for_o find_v out_o the_o true_a south_n and_o north_n point_n which_o be_v in_o effect_n very_o difficult_a to_o know_v take_v therefore_o four_o piece_n of_o timber_n each_o one_o of_o they_o five_o foot_n long_o and_o about_o six_o inch_n thick_a square-wise_a sharpen_v their_o end_n and_o fix_v they_o so_o in_o the_o ground_n that_o they_o may_v stand_v perpendicular_a and_o as_o near_o to_o south_n and_o north_n by_o a_o magnetic_a needle_n
age_n have_v reject_v the_o old_a opinion_n of_o the_o earth_n nourish_v of_o plant_n or_o be_v convert_v into_o their_o aliment_n have_v make_v many_o laudable_a experiment_n for_o find_v out_o the_o material_n and_o mean_n of_o their_o growth_n and_o vegetation_n such_o as_o sir_n francis_n bacon_n observe_v of_o germination_n helmont_n of_o a_o willow_n and_o the_o noble_a mr._n boyl_n of_o a_o gourd_n etc._n etc._n for_o though_o a_o tree_n be_v cut_v down_o and_o the_o root_n thereof_o wax_v old_a in_o the_o earth_n and_o the_o stock_n die_v in_o the_o ground_n yet_o through_o the_o send_v of_o water_n it_o will_v bud_v as_o job_n speak_v chap._n 14._o 7_o 8_o 9_o i_o shall_v add_v a_o short_a remark_n of_o a_o willow_n grow_v without_o earth_n upon_o the_o 13_o of_o april_n 1662._o i_o set_v a_o top_n branch_n of_o the_o peach-leafed_a willow_n in_o a_o glass-viol_n among_o 12_o ounce_n of_o pure_a spring_n water_n with_o three_o small_a bud_n upon_o the_o top_n thereof_o scarce_o yet_o discernible_a the_o first_o ten_o or_o twelve_o day_n little_a white_a speck_n appear_v upon_o the_o side_n of_o the_o willow_n like_o small_a drop_n of_o quicksilver_n or_o like_o the_o first_o bubble_n that_o arise_v upon_o the_o fermentation_n of_o ale_n or_o wine_n but_o no_o consumption_n of_o the_o water_n all_o this_o time_n indeed_o the_o gem_n which_o stand_v three_o inch_n above_o the_o water_n do_v visible_o swell_v about_o the_o twelve_o day_n about_o the_o fifteen_o day_n i_o perceive_v small_a white_a root_n within_o the_o water_n upon_o several_a place_n of_o the_o plant_n and_o observe_v the_o liquor_n grow_v somewhat_o thick_a and_o decay_v in_o bulk_n considerable_o have_v perceive_v this_o i_o take_v another_o glass_n of_o the_o same_o bigness_n with_o that_o wherein_o the_o willow_n grow_v and_o have_v fill_v both_o topful_a with_o spring_n water_n i_o observe_v clear_o the_o consumption_n of_o the_o water_n wherein_o the_o plant_n stand_v to_o be_v so_o great_a that_o during_o may_n june_n and_o a_o great_a part_n of_o july_n every_o week_n at_o least_o a_o ounce_n and_o a_o half_a or_o two_o ounce_n of_o it_o be_v insensible_o spend_v whereas_o the_o other_o water_n stand_v by_o in_o a_o open_a vessel_n of_o the_o same_o size_n make_v not_o waste_v of_o one_o spoonful_n in_o a_o whole_a month_n about_o the_o middle_n of_o august_n the_o water_n turn_v very_o thick_a and_o green_a like_o that_o whereon_o duck-weed_n use_v to_o grow_v and_o the_o fair_a white_a root_n be_v all_o obscure_v from_o the_o sight_n although_o the_o vessel_n by_o the_o multitude_n of_o root_n be_v not_o capable_a of_o the_o three_o part_n of_o water_n it_o receive_v at_o first_o at_o this_o time_n the_o branch_n be_v advance_v to_o half_a the_o bigness_n and_o a_o much_o great_a length_n than_o the_o whole_a stock_n at_o its_o first_o plant_n and_o the_o leaf_n of_o as_o fresh_a a_o verdure_n as_o any_o willow_n in_o the_o field_n thus_o have_v observe_v that_o a_o tree_n of_o four_o ounce_n weight_n can_v in_o three_o month_n time_n and_o little_o more_o consume_v insensible_o seven_o or_o eight_o time_n its_o own_o weight_n of_o pure_a water_n without_o the_o warm_a preservation_n of_o the_o earth_n and_o by_o its_o own_o proper_a digestion_n to_o thicken_v the_o remnant_n of_o the_o water_n that_o it_o may_v serve_v for_o lorication_n of_o the_o tender_a fibres_fw-fr of_o the_o root_n i_o take_v the_o glass_n the_o tree_n and_o all_o and_o throw_v they_o over_o a_o window_n suppose_v it_o needless_a to_o recruit_v the_o water_n any_o more_o and_o judge_v it_o impossible_a without_o the_o warm_a guard_n of_o the_o earth_n that_o the_o naked_a tree_n can_v be_v preserve_v in_o winter_n yet_o it_o have_v the_o good_a fortune_n to_o fall_v among_o some_o thick_a herb_n in_o the_o corner_n of_o a_o little_a garden_n where_o after_o it_o have_v lie_v all_o winter_n it_o be_v find_v and_o bring_v back_o to_o i_o the_o branch_n fair_o bud_v in_o april_n the_o whole_a tree_n fresh_a and_o green_a yet_o very_o little_a water_n be_v leave_v in_o the_o glass_n by_o reason_n as_o i_o judge_v it_o have_v fall_v upon_o its_o side_n then_o i_o endeavour_v to_o keep_v water_n about_o it_o but_o the_o stock_n fill_v the_o neck_n of_o the_o viol_n and_o the_o root_n the_o whole_a body_n thereof_o the_o starve_a plant_n die_v in_o may_n after_o it_o have_v live_v a_o whole_a year_n without_o earth_n from_o this_o it_o will_v seem_v that_o this_o kind_n of_o tree_n and_o it_o may_v be_v many_o more_o do_v dissipat_v insensible_o six_o time_n more_o liquor_n than_o it_o do_v assimilar_v and_o by_o consequence_n that_o a_o great_a quantity_n of_o moisture_n be_v necessary_a for_o maintenance_n of_o great_a wood_n neither_o be_v there_o any_o way_n so_o advantageous_a for_o drain_n moist_a ground_n where_o there_o be_v no_o live_a spring_n as_o that_o of_o plant_v abundance_n of_o timber_n which_o will_v best_o agree_v with_o that_o kind_n of_o soil_n for_o by_o this_o mean_n what_o be_v former_o noisome_a and_o superfluous_a be_v now_o convert_v partly_o into_o the_o useful_a aliment_n of_o the_o timber_n and_o partly_o send_v abroad_o in_o insensible_a exhalation_n which_o according_a to_o the_o nature_n of_o the_o emit_v plant_n prove_v either_o very_a noisome_a or_o wholesome_a to_o the_o neighbour-inhabitant_n great_a care_n therefore_o will_v be_v have_v in_o the_o choice_n of_o such_o tree_n as_o be_v to_o be_v plant_v in_o such_o moist_a ground_n as_o be_v near_o to_o man_n dwelling_n or_o place_n of_o concourse_n they_o be_v not_o fool_n who_o prefer_v fir_n and_o lime-tree_n in_o their_o avenue_n to_o oak_n and_o elm_n let_v the_o effect_n of_o the_o atomical_a exhalation_n of_o alder_n and_o oak_n upon_o fine_a linen_n and_o white_a skin_n be_v more_o particular_o notice_v have_v speak_v somewhat_o of_o the_o aliment_n and_o growth_n of_o plant_n i_o shall_v in_o the_o next_o place_n give_v a_o short_a hint_n at_o the_o motion_n of_o their_o aliment_n especial_o of_o tree_n that_o the_o alimentary_a juice_n of_o plant_n be_v much_o thin_a than_o that_o of_o animal_n no_o man_n i_o suppose_v will_v deny_v see_v that_o be_v convey_v through_o the_o trunk_n or_o body_n of_o the_o plant_n by_o inperceptible_a pore_n but_o this_o for_o the_o most_o part_n be_v send_v through_o all_o the_o member_n through_o patent_n and_o manifest_a vessel_n but_o how_o the_o nourish_a and_o vital_a juice_n in_o plant_n do_v move_v and_o by_o what_o passage_n have_v not_o yet_o be_v make_v know_v by_o any_o that_o i_o have_v see_v i_o make_v once_o a_o few_o observation_n for_o try_v of_o the_o motion_n of_o the_o aliment_n of_o tree_n which_o breed_v in_o i_o this_o conjecture_n the_o nutritive_a juice_n of_o tree_n be_v transmit_v both_o to_o the_o root_n and_o branch_n through_o the_o heart_n or_o pitch_n and_o woody_a pore_n of_o the_o timber_n and_o when_o it_o be_v come_v to_o the_o extreme_a part_n it_o return_v again_o from_o the_o top_n of_o the_o root_n and_o branch_n between_o the_o bark_n and_o timber_n into_o these_o forename_a interior_a passage_n and_o so_o back_o to_o the_o extremity_n again_o and_o that_o continual_o so_o long_o as_o the_o life_n remain_v and_o because_o the_o substance_n of_o that_o skin_n or_o bark_n which_o invest_v the_o fibre_n of_o the_o root_n be_v more_o open_a and_o porous_a than_o that_o which_o be_v upon_o the_o outward_a branch_n therefore_o it_o seem_v that_o so_o much_o as_o be_v superad_v to_o the_o stock_n of_o the_o former_a aliment_n from_o the_o earth_n be_v convey_v to_o the_o heart_n and_o pitch_n by_o mean_n of_o and_o together_o with_o that_o part_n of_o the_o retrograd_v juice_n which_o return_v from_o nourish_v and_o enliven_a the_o timber_n of_o the_o root-branche_n for_o it_o be_v a_o easy_a experiment_n to_o make_v the_o top_n of_o any_o tree_n become_v root_n by_o lay_v it_o down_o and_o receive_v the_o impression_n of_o the_o life_n of_o the_o tree_n common_a to_o the_o whole_a mass_n of_o alimentary_a juice_n like_o the_o i_o will_v in_o animal_n mix_v with_o the_o blood_n of_o the_o veni-cave_n before_o it_o come_v to_o the_o heart_n this_o motion_n be_v not_o to_o be_v think_v always_o alike_o swift_a or_o of_o equal_a celerity_n for_o the_o vital_a juice_n of_o the_o tree_n become_v so_o thick_a and_o oleagenous_a in_o the_o winter_n that_o the_o motion_n thereof_o to_o the_o outward_a be_v scarce_o discernible_a though_o the_o preparation_n of_o the_o gem_n both_o for_o leaf_n and_o flower_n be_v observe_v by_o the_o curious_a and_o can_v be_v distinguish_v even_o in_o the_o cold_a season_n and_o the_o return_v inward_a be_v in_o so_o small_a quantity_n that_o they_o be_v rather_o like_o
full_a of_o oil_n and_o that_o be_v as_o they_o call_v they_o fat_a coal_n there_o be_v a_o certain_a fire_n which_o be_v as_o a_o meteor_n and_o i_o judge_v that_o from_o its_o resemblance_n to_o ignis_fw-la fatâ—â—s_fw-la which_o the_o vulgar_a term_v wild_a fire_n it_o have_v the_o saâ—e_v name_n it_o seem_v to_o be_v compose_v of_o some_o fat_a oily_a vapour_n that_o go_v out_o of_o the_o coal_n the_o pore_n thereof_o be_v once_o open_v which_o be_v kindle_v after_o the_o same_o manner_n as_o those_o fire_n above_o ground_n be_v which_o be_v most_o ordinary_o find_v in_o fat_a and_o marish_a ground_n of_o this_o fire_n it_o be_v report_v that_o in_o the_o day_n time_n while_o the_o work_v man_n be_v work_v in_o the_o coal-roome_n it_o come_v to_o no_o height_n though_o it_o be_v sometime_o see_v in_o little_a hole_n of_o the_o coal-wall_n shine_v like_o kindle_a sulphur_n but_o without_o force_n but_o when_o the_o workman_n be_v once_o remove_v and_o have_v stay_v out_o all_o night_n it_o gather_v to_o such_o a_o strength_n that_o at_o its_o first_o encounter_v with_o fire_n which_o the_o coal-hewers_a be_v necessitate_v to_o have_v by_o take_v in_o of_o light_n it_o break_v out_o with_o such_o a_o violence_n that_o it_o kill_v any_o person_n it_o find_v in_o its_o way_n the_o reason_n why_o it_o be_v without_o this_o force_n while_o the_o workman_n be_v in_o the_o place_n seem_v to_o be_v this_o that_o they_o work_v with_o such_o violence_n and_o motion_n as_o they_o do_v do_v certain_o move_v the_o air_n considerable_o it_o be_v contain_v in_o so_o narrow_a a_o place_n as_o a_o coal-room_n and_o this_o air_n be_v violent_v by_o motion_n move_v that_o oily_a vapour_n whereof_o the_o fire_n be_v form_v so_o that_o it_o get_v not_o liberty_n to_o unit_fw-la itself_o be_v dissipate_v by_o the_o motion_n of_o the_o air._n but_o so_o soon_o as_o the_o air_n be_v still_o and_o quiet_a after_o the_o workman_n be_v go_v home_o it_o unit_v itself_o and_o gather_v force_v and_o therefore_o so_o soon_o as_o it_o meet_v with_o fire_n which_o be_v more_o forcible_a than_o the_o flame_n that_o be_v kindle_v in_o it_o it_o rarifi_v the_o sulphurous_a part_n be_v kindle_v and_o force_v itself_o out_o as_o powder_v out_o of_o a_o gun_n for_o it_o have_v be_v observe_v that_o if_o any_o person_n stay_v in_o the_o coal-sink_a while_o it_o break_v within_o the_o coal-room_n they_o be_v in_o danger_n of_o be_v kill_v the_o ordinary_a way_n by_o which_o the_o hurt_n of_o it_o be_v prevent_v be_v by_o a_o person_n that_o enter_v before_o the_o workman_n who_o be_v cover_v with_o wetâ—sack-cloath_n when_o he_o come_v near_o the_o coal-wall_n where_o the_o fire_n be_v fear_v he_o creep_v on_o his_o belly_n with_o a_o long_a poll_n before_o he_o with_o a_o light_a candle_n on_o the_o end_n thereof_o with_o who_o flame_n the_o wildfire_n meeting_n break_v with_o violence_n and_o run_v along_v the_o roof_n go_v out_o with_o a_o noise_n at_o the_o mouth_n of_o the_o sink_v the_o person_n that_o give_v fire_n have_v escape_v by_o creep_v on_o the_o ground_n and_o keep_v his_o face_n close_o to_o it_o till_o it_o be_v over-passed_n which_o be_v in_o a_o moment_n the_o place_n where_o this_o be_v most_o know_v be_v in_o a_o coal_n be-west_n leith_n in_o a_o piece_n of_o land_n call_v werdy_o which_o for_o want_v of_o level_n and_o the_o violence_n of_o that_o fire_n the_o owner_n be_v force_v to_o abandon_v i_o come_v now_o to_o the_o last_o part_n which_o i_o promise_v to_o speak_v of_o namely_o of_o the_o best_a way_n for_o try_v of_o ground_n to_o find_v coal_n where_o never_o any_o have_v hitherto_o be_v discover_v and_o of_o carry_v on_o of_o level_n for_o drain_n the_o water_n of_o coal_n and_o make_v it_o workable_a as_o to_o the_o first_o part_n there_o be_v but_o three_o way_n first_o by_o sink_v which_o be_v most_o chargeable_a in_o regard_n that_o in_o such_o ground_n where_o the_o metal_n be_v all_o entire_a water_n abound_v and_o this_o do_v not_o only_o bring_v the_o master_n under_o a_o necessity_n of_o great_a expense_n for_o draw_v the_o water_n but_o also_o render_v it_o impossible_a to_o get_v sink_v to_o any_o deepness_n which_o may_v suffice_v for_o give_v a_o account_n of_o all_o the_o metal_n to_o be_v find_v within_o the_o field_n that_o may_v be_v render_v workable_a there_o be_v a_o second_o way_n invent_v to_o supply_v this_o defect_n which_o be_v by_o boar_v with_o a_o instrument_n make_v of_o several_a rod_n of_o iron_n which_o boar_v through_o the_o metal_n and_o try_v they_o this_o way_n in_o my_o opinion_n be_v worse_a than_o the_o former_a for_o first_o if_o the_o coal_n lie_v deep_a in_o the_o place_n where_o you_o try_v by_o boar_v it_o become_v almost_o as_o tedious_a and_o expensive_a as_o sink_v the_o draw_v of_o the_o â—odes_n consume_v so_o much_o time_n in_o regard_n it_o must_v be_v frequent_o do_v next_o in_o boar_v suppose_v the_o nature_n of_o the_o metal_n be_v find_v yet_o thereby_o their_o course_n can_v never_o be_v know_v till_o they_o be_v sink_v which_o be_v one_o of_o the_o thing_n most_o considerable_a in_o the_o search_n of_o a_o coal_n because_o thereby_o be_v know_v whether_o it_o be_v workable_a with_o advantage_n or_o not_o and_o whether_o it_o be_v possible_a to_o draw_v water_n from_o it_o by_o a_o level_n or_o otherwise_o last_o this_o way_n leave_v the_o master_n at_o a_o uncertainty_n notwithstanding_o the_o coal_n have_v be_v find_v of_o its_o goodness_n as_o to_o its_o nature_n and_o as_o to_o its_o thickness_n as_o to_o its_o goodness_n because_o all_o that_o be_v find_v of_o the_o coal_n by_o this_o boar_a instrument_n be_v some_o small_a drâ—ss_n which_o remain_v after_o the_o wash_n of_o the_o thing_n that_o be_v bring_v up_o in_o the_o wumble_a by_o which_o none_o can_v judge_v of_o its_o goodness_n or_o badness_n as_o to_o its_o thickness_n because_o it_o be_v impossible_a to_o discern_v exact_o when_o the_o boaring-instrument_n have_v pass_v the_o coal_n all_o the_o rule_n for_o try_v thereof_o be_v the_o kind_n of_o metal_n that_o be_v bring_v up_o in_o the_o wumble_a now_o i_o have_v know_v in_o my_o experience_n a_o coal_n bore_v which_o the_o boarer_fw-la by_o that_o rule_n have_v judge_v four_o foot_n in_o thickness_n yet_o when_o it_o come_v to_o be_v sink_v have_v not_o prove_v one_o the_o reason_n whereof_o be_v obvious_a because_o the_o boaring-iron_n be_v long_o and_o weighty_a in_o lift_v they_o up_o and_o down_o they_o break_v the_o coal_n already_o pierce_v and_o this_o fall_a down_o among_o the_o metal_n they_o be_v pierce_v and_o be_v find_v in_o the_o wumble_a with_o they_o especial_o when_o the_o metal_n under_o the_o coal_n be_v a_o black_a till_o give_v ground_n to_o imagine_v that_o all_o that_o time_n they_o have_v be_v pierce_v a_o coal_n and_o so_o consequent_o the_o coal_n must_v be_v of_o such_o a_o thickness_n the_o last_o and_o best_a way_n of_o trial_n be_v that_o which_o be_v term_v a_o range_v over_o the_o metal_n for_o do_v whereof_o this_o method_n be_v to_o be_v observe_v suppose_v there_o be_v any_o place_n within_o the_o ground_n to_o be_v search_v where_o the_o course_n of_o metal_n can_v be_v see_v as_o in_o the_o bank_n of_o a_o river_n or_o rivulet_n or_o sea-bank_n when_o the_o place_n be_v near_o the_o sea_n than_o consideration_n must_v be_v have_v how_o far_o the_o low_a of_o these_o metal_n can_v go_v before_o they_o crop_v out_o to_o the_o grass_n which_o will_v be_v know_v by_o observe_v the_o dipp_n or_o declination_n of_o the_o metal_n and_o the_o rise_v of_o the_o ground_n above_o whereof_o a_o just_a allowance_n must_v be_v give_v and_o have_v dig_v before_o the_o say_a crop_n you_o shall_v certain_o find_v the_o metal_n that_o be_v next_o under_o it_o and_o if_o that_o prove_v not_o coal_n keep_v the_o former_a proportion_n you_o must_v advance_v and_o dig_v before_o its_o crop_n and_o so_o shall_v you_o find_v the_o next_o metal_n 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pillar_n high_o without_o any_o alteration_n at_o least_o considerable_a in_o the_o weight_n for_o it_o still_o remain_v a_o foot_n of_o water_n whatever_o be_v the_o height_n of_o the_o pillar_n above_o it_o last_o the_o weight_n of_o a_o fluid_a be_v essential_a to_o it_o but_o the_o pressure_n be_v only_o accidental_a because_o it_o be_v only_o generate_v and_o beget_v in_o the_o inferior_a part_n by_o the_o weight_n of_o the_o superior_a which_o weight_n may_v be_v take_v away_o theorem_fw-la xxiii_o though_o the_o bensil_n of_o a_o fluid_a be_v not_o the_o same_o thing_n formal_o with_o the_o weight_n yet_o be_v they_o the_o same_o effective_o this_o proposition_n be_v true_a in_o order_n to_o many_o other_o thing_n beside_o fluids_n for_o we_o see_v that_o the_o sun_n and_o fire_n be_v formal_o different_a yet_o they_o may_v be_v the_o same_o effective_o because_o the_o same_o effect_n that_o be_v do_v by_o the_o heat_n of_o the_o sun_n may_v be_v do_v by_o the_o heat_n of_o the_o fire_n so_o the_o same_o effect_n that_o be_v produce_v by_o the_o weight_n of_o a_o fluid_a may_v be_v do_v by_o the_o pressure_n and_o bensill_n of_o it_o thus_o the_o mercurial_a cylinder_n in_o the_o torricellian_a experiment_n may_v be_v either_o sustain_v by_o the_o bensil_n of_o the_o air_n or_o the_o weight_n of_o it_o by_o the_o bensil_n as_o when_o no_o more_o air_n be_v admit_v to_o rest_n upon_o the_o stagnant_a mercury_n than_o three_o or_o four_o inch_n the_o rest_n be_v seclude_v by_o stop_v the_o orifice_n of_o the_o vessel_n by_o the_o weight_n of_o it_o as_o when_o a_o entire_a pillar_n of_o air_n from_o the_o top_n of_o the_o atmosphere_n rest_v upon_o the_o face_n of_o the_o stagnant_a quicksilver_n it_o be_v also_o evident_a in_o a_o clock_n which_o may_v be_v make_v to_o move_v either_o by_o a_o weight_n of_o lead_n or_o by_o the_o force_n and_o power_n of_o a_o steel_n spring_n theorem_fw-la xxiv_o the_o surface_n of_o water_n be_v able_a to_o sustain_v 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c_o d._n next_o that_o above_o the_o stagnant_a mercury_n there_o be_v thirty_o four_o foot_n of_o water_n rest_v namely_o a_o b_o e_o f._n last_o that_o upon_o the_o surface_n of_o the_o say_a water_n there_o be_v rest_v the_o element_n of_o air_n g_o h_o a_o b_o who_o top_n g_o h_n i_o reckon_v to_o be_v about_o six_o thousand_o fathom_n above_o a_o b._n beside_o these_o let_v we_o imagine_v that_o there_o be_v here_o three_o pipe_n open_a at_o both_o end_n the_o first_o whereof_o c_z a_o g_z have_v it_o be_v low_a orifice_n c_o drown_v among_o the_o stagnant_a mercury_n e_o f_o c_o d_o go_v so_o high_a that_o theu_o p_a orifice_n go_v above_o the_o top_n of_o the_o air_n g_o h._n the_o second_o who_o low_a orifice_n i_o be_v only_o drown_v among_o the_o water_n a_o b_o e_o f_o reach_v to_o the_o top_n of_o the_o air_n likewise_o the_o three_o who_o open_a end_n k_o be_v above_o the_o surface_n of_o the_o water_n a_o n_o b_o and_o hang_v in_o the_o open_a air_n go_v likewise_o above_o the_o atmosphere_n these_o thing_n be_v suppose_v we_o see_v that_o no_o fluid_n can_v by_o its_o own_o proper_a weight_n press_v any_o part_n of_o itself_o high_a than_o it_o be_v own_o surface_n see_v the_o stagnant_a mercury_n e_o f_o c_o d_o can_v press_v itself_o within_o the_o pipe_n c_o g_o high_o than_o e._n neither_o can_v the_o water_n a_o b_o e_o f_o press_v itself_o high_a within_o the_o pipe_n i_o l_o then_z the_o point_n n._n last_o neither_o can_v the_o air_n g_o h_o a_o b_o press_v itself_o within_o the_o pipe_n k_o m_o high_a than_o m._n but_o when_o one_o fluid_a press_v upon_o another_o as_o the_o water_n a_o b_o e_o f_o upon_o the_o mercury_n e_o f_o c_o d_o then_o do_v the_o say_a mercury_n ascend_v high_a than_o it_o be_v own_o surface_n namely_o from_o e_z to_z o_o which_o point_n be_v the_o high_a to_o which_o the_o thirty_o four_o foot_n of_o water_n a_o b_o e_o f_o can_v raise_v the_o mercury_n which_o altitude_n be_v twenty_o nine_o inch_n above_o the_o surface_n e_o i_o f._n but_o if_o a_o second_o fluid_fw-la be_v superad_v as_o the_o whole_a air_n g_o h_o a_o b_o then_o must_v the_o mercury_n according_a to_o that_o new_a pressure_n rise_v by_o proportion_n so_o rise_v the_o mercury_n from_o o_o to_o p_o other_o twenty_o nine_o inch_n by_o this_o same_o additional_a weight_n of_o air_n the_o water_n rise_v thirty_o four_o foot_n in_o the_o pipe_n i_o l_o namely_o from_o n_o to_o r._n now_o i_o say_v the_o outmost_a and_o high_a point_n to_o which_o the_o element_n of_o air_n g_o h_o a_o b_o can_v raise_v the_o mercury_n be_v from_o o_o to_o p_o for_o by_o the_o pressure_n of_o the_o water_n a_o b_o e_o f_o it_o rise_v from_o e_z to_z o._n and_o the_o high_a point_n to_o which_o the_o say_a air_n can_v raise_v the_o water_n be_v from_o n_o to_o r._n the_o reason_n of_o these_o determinate_a altitude_n must_v be_v seek_v for_o from_o the_o altitude_n of_o the_o incumb_a and_o press_v fluid_n for_o as_o these_o be_v less_o or_o more_o so_o be_v the_o altitude_n of_o the_o mercury_n and_o of_o the_o water_n within_o the_o pipe_n more_o or_o less_o the_o hight_v therefore_o of_o the_o mercury_n e_o o_fw-fr be_v twenty_o nine_o inch_n because_o the_o deepness_n of_o the_o press_a water_n a_o b_o e_o f_o be_v thirty_o four_o foot_n and_o the_o height_n of_o the_o water_n n_o r_o be_v thirty_o four_o foot_n because_o the_o height_n of_o the_o air_n g_o h_n above_o a_o b_o be_v six_o thousand_o fathom_n or_o thereabouts_o and_o for_o the_o same_o reason_n be_v the_o mercury_n o_o p_o twenty_o nine_o inch_n theorem_fw-la xxvii_o