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that_o deepness_n with_o the_o pressure_n of_o the_o air_n above_o will_v be_v equivalent_a to_o the_o weight_n of_o a_o pillar_n of_o mercury_n 87_o inch_n high_a and_o three_o inch_n thick_a which_o will_v exceed_v in_o real_a weight_n 200_o pound_n if_o so_o much_o rest_n upon_o the_o palm_n how_o much_o must_v rest_v upon_o the_o rest_n of_o the_o part_n of_o the_o body_n let_v we_o suppose_v then_o the_o quantity_n of_o the_o palm_n to_o be_v find_v in_o a_o man_n skin_n 200_o time_n then_o must_v he_o suffer_v as_o much_o pressure_n and_o actual_o support_v as_o much_o burden_n as_o will_v amount_v to_o 40000_o pound_n weight_n seven_o our_o body_n may_v be_v under_o a_o huge_a pressure_n and_o yet_o that_o burden_n not_o perceptible_a as_o be_v evident_a from_o the_o diver_n who_o find_v little_a or_o no_o weight_n while_o he_o be_v under_o the_o water_n or_o if_o there_o be_v any_o pressure_n find_v it_o be_v not_o comparable_a to_o that_o which_o real_o be_v eight_o when_o a_o man_n be_v 14_o or_o 15_o fathom_n down_o at_o every_o inspiration_n and_o expiration_n his_o breast_n and_o belly_n must_v lift_v up_o the_o weight_n of_o 1800_o pound_n because_o if_o the_o whole_a burden_n be_v 40000_o the_o weight_n that_o rest_v upon_o the_o breast_n and_o belly_n will_v be_v about_o 1800._o nine_o that_o between_o every_o inspiration_n and_o expiration_n there_o happen_v a_o perfect_a counterpoise_n namely_o by_o the_o air_n that_o go_v into_o the_o lung_n and_o the_o outward_a air_n of_o the_o ark_n for_o if_o the_o pressure_n of_o the_o one_o be_v more_o than_o the_o pressure_n of_o the_o other_o there_o can_v be_v no_o motion_n of_o the_o lung_n ten_o when_o a_o man_n draw_v his_o breath_n the_o air_n come_v not_o in_o by_o suction_n but_o by_o pulsion_n for_o this_o cause_n though_o the_o windpipe_n be_v stop_v yet_o a_o man_n may_v live_v by_o have_v a_o hole_n in_o his_o side_n go_v into_o the_o lung_n last_o that_o there_o be_v no_o such_o thing_n as_o suction_n proper_o and_o therefore_o the_o motion_n of_o all_o fluid_a body_n be_v cause_v by_o pressure_n and_o weight_n the_o motion_n of_o the_o blood_n then_o through_o the_o heart_n be_v drive_v and_o not_o suct_v infant_n proper_o do_v not_o suck_v but_o have_v the_o milk_n squeeze_v into_o their_o mouth_n it_o be_v evident_a from_o the_o sucking-glass_n that_o some_o woman_n use_v for_o milk_v their_o own_o breast_n for_o by_o help_n of_o this_o the_o air_n that_o guard_v the_o head_n of_o the_o pap_n be_v remove_v and_o so_o the_o air_n that_o press_v the_o part_n about_o and_o without_o squeeze_v out_o the_o milk_n fig._n 25_o pag._n 179_o experiment_n xix_o figure_n 26._o this_o figure_n
poet._n acventâ—_n velut_fw-la agmine_fw-la fâ—cto_fw-la qua_fw-la data_fw-la porâ—â—â—unt_fw-la &_o terras_fw-la turbine_fw-la perâ—â—â—nt_fw-la incubuere_fw-la mari_fw-fr toâ—â—mque_fw-la a_o sellâ—us_a imâ—s_n una_fw-la euâ—uâ—que_fw-la noâ—â—sque_fw-la enâ—nt_fw-la creâ—erque_fw-la procelâ—â—a_fw-la africus_n &_o vastoâ—_n volvunt_fw-la ad_fw-la littora_fw-la fluctus_fw-la tempectâ—â—â—ine_fw-la more_o â—urit_n tonâ—â—â—â—que_fw-la trenâ—seunt_fw-la ardua_fw-la terraâ—um_fw-la tropic_n &_o littora_fw-la circum_fw-la wind_n at_o his_o mutinous_a â—ands_n force_v their_o own_o way_n and_o thunder_n through_o the_o strand_n they_o take_v the_o sea_n eurus_n and_o notus_fw-la rave_v and_o stormy_a africus_n from_o deep_a cave_n when_o tempâ—storage_n and_o jove_n great_a cannon_n reaâ—_n the_o mountain_n quake_v the_o plain_n and_o every_o shoar_n the_o first_o rule_n be_v the_o further_a up_o the_o metal_n go_v the_o wether_n incline_v to_o be_v the_o fair_a and_o the_o further_a it_o fall_v down_o it_o incline_v to_o be_v the_o foul_a second_o when_o it_o be_v high_o fair_a wether_n be_v universal_a when_o it_o be_v low_a foul_a wether_n be_v universal_a three_o it_o be_v not_o so_o much_o fair_a or_o foul_a wether_n actual_o which_o influence_n the_o quicksilver_n as_o it_o be_v the_o disposition_n and_o inclination_n of_o the_o wether_n to_o be_v fair_a or_o foul._n note_v that_o n._n e._n and_o e._n wind_n even_o with_o raâ—n_n do_v raise_v the_o mercury_n and_o keep_v it_o up_o sometime_o beyond_o ordinary_a and_o as_o it_o show_v the_o nature_n of_o the_o wether_n so_o it_o foretell_v which_o be_v the_o great_a excellency_n of_o it_o sometime_o a_o day_n sometime_o two_o sometime_o three_o or_o four_o before_o any_o change_n of_o wether_n come_v the_o metal_n rise_v and_o fall_v quick_o when_o fair_a or_o foul_a wether_n be_v nigh_o at_o hand_n it_o do_v not_o so_o much_o foretell_v wind_n as_o it_o be_v actual_o influence_v by_o they_o when_o they_o blow_v 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ridiculous_a the_o same_o difficulty_n we_o find_v in_o the_o shell_n of_o snail_n who_o screw_n and_o spiral_n line_n go_v right_o about_o with_o the_o sun_n and_o in_o the_o shell_n of_o sea-snail_n common_o call_v buckies_n some_o affirm_v that_o upon_o the_o south_n of_o the_o line_n the_o shell_n of_o these_o creature_n be_v screw_v leave_v about_o which_o be_v worthy_a of_o observation_n it_o be_v easy_a to_o give_v the_o reason_n why_o a_o lute_n string_n turn_v about_o such_o a_o way_n with_o moisture_n because_o while_o it_o be_v twine_v by_o the_o artist_n the_o wheel_n or_o spindle_n go_v such_o a_o way_n about_o wherewith_o he_o twist_v it_o but_o who_o can_v say_v the_o like_a of_o the_o awin_n see_v the_o great_a artist_n be_v god_n and_o nature_n who_o work_a and_o manner_n of_o work_v be_v unknown_a to_o we_o 〈◊〉_d be_v ask_v what_o way_n go_v about_o the_o hool_n of_o the_o wild_a vetch_n i_o answer_v which_o be_v a_o notable_a speculation_n the_o one_o hool_n go_v right_o about_o with_o the_o sun_n by_o moisture_n as_o the_o awin_n do_v and_o consequent_o leave_v about_o with_o dryness_n but_o the_o other_o go_v right_o about_o with_o dryness_n and_o leave_v about_o with_o moisture_n contrary_a to_o the_o motion_n of_o its_o fellow_n hool_n this_o be_v see_v sensible_o by_o hold_v they_o nigh_o the_o fire_n the_o same_o hold_v true_a in_o the_o two_o hool_n of_o the_o right_a pea-cod_n i_o suppose_v that_o the_o hool_n of_o brom-seed_n may_v do_v the_o like_a another_o experiment_n i_o make_v with_o the_o hygroscope_n in_o place_v it_o within_o the_o receiver_n of_o the_o air-pump_n at_o the_o very_a first_o exsuction_n of_o the_o air_n the_o index_n move_v leave_v about_o most_o sensible_o and_o by_o the_o several_a exsuction_n which_o be_v make_v one_o after_o another_o it_o advance_v half_o a_o circle_n about_o it_o have_v be_v easy_a to_o have_v make_v it_o
pillar_n of_o mercury_n each_o one_o of_o they_o 29_o inch_n high_a it_o follow_v of_o necessity_n that_o the_o mercury_n within_o the_o tub_n must_v be_v as_o high_a as_o r._n it_o be_v no_o wonder_n to_o see_v the_o silver_n halt_v at_o r_o provide_v rx_n and_o zs_n be_v two_o bulk_n of_o mercury_n environ_v the_o pipe_n as_o the_o outward_a water_n environ_n the_o wide_a and_o narrow_a pipe_n neither_o aught_o any_o to_o wonder_v when_o the_o silver_n fall_v down_o and_o rest_v at_o r_o nothing_o environ_v the_o pipe_n but_o air_n see_v the_o pressure_n of_o the_o air_n be_v equivalent_a to_o the_o weight_n of_o 29_o inch_n of_o quicksilver_n this_o experiment_n be_v easy_o make_v take_v therefore_o a_o slender_a glass-pipe_n of_o any_o length_n beyond_o 30_o inch_n open_a at_o both_o end_n but_o the_o low_a end_n q_n must_v be_v draw_v so_o small_a by_o a_o flame_n of_o a_o lamp_n that_o the_o entry_n may_v be_v no_o wide_o than_o may_v admit_v the_o point_n of_o a_o small_a needle_n or_o the_o hair_n of_o one_o head_n then_o stop_v the_o say_a orifice_n pour_v in_o mercury_n above_o at_o the_o orifice_n n_o till_o the_o pipe_n be_v complete_o full_a next_o close_o the_o say_a orifice_n with_o wet_a paper_n and_o the_o pulp_n of_o your_o finger_n and_o open_v the_o low_a orifice_n you_o shall_v find_v which_o be_v very_o delightful_a to_o behold_v the_o mercury_n spring_v out_o like_v unto_o a_o small_a silver_n thread_n and_o fall_v down_o from_o the_o top_n n_o shall_v rest_v at_o r_o the_o motion_n cease_v at_o the_o narrow_a orifice_n q._n this_o show_v evident_o that_o there_o be_v not_o need_v always_o of_o stagnant_a mercury_n for_o try_v the_o torricellian_a experiment_n but_o only_o when_o the_o mouth_n of_o the_o pipe_n below_o be_v wide_a for_o be_v narrow_a the_o silver_n run_v slow_o out_o and_o consequent_o subside_v slow_o above_o and_o come_v down_o slow_o to_o r_o there_o rest_v but_o when_o the_o mouth_n be_v wide_o below_o the_o silver_n fall_v down_o so_o quick_o that_o it_o go_v beyond_o r_o before_o it_o can_v recover_v itself_o which_o recovery_n will_v never_o be_v unless_o there_o be_v stagnant_a mercury_n to_o run_v up_o again_o from_o what_o be_v say_v we_o see_v first_o that_o when_o one_o part_n of_o a_o surface_n of_o water_n or_o air_n be_v more_o burden_a than_o another_o the_o burden_a part_n present_o yield_v till_o it_o be_v no_o more_o burden_a than_o the_o other_o this_o be_v clear_a from_o the_o fall_n down_o of_o the_o water_n from_o e_z to_z g_z which_o can_v be_v support_v by_o the_o part_n i_o because_o more_o burden_a than_o the_o rest_n we_o see_v second_o that_o the_o element_n of_o air_n rest_v upon_o the_o surface_v of_o all_o body_n with_o a_o considerable_a weight_n otherwise_o it_o can_v not_o sustain_v the_o water_n before_o it_o fall_v down_o from_o e_z to_z g_z for_o if_o it_o do_v not_o rest_n upon_o the_o surface_n mh_o with_o weight_n the_o water_n can_v never_o be_v suspend_v see_v the_o application_n of_o the_o finger_n to_o the_o orifice_n e_o be_v only_o the_o accidental_a cause_n of_o this_o sustentation_n we_o see_v three_o that_o according_a to_o the_o difference_n of_o natural_a weight_n between_o two_o fluid_n so_o be_v the_o proportion_n of_o altitude_n between_o two_o of_o their_o cylinder_n therefore_o air_n be_v reckon_v 14000_o time_n light_a than_o mercury_n it_o follow_v that_o the_o cylinder_n of_o mercury_n sustain_v by_o the_o air_n must_v be_v 14000_o time_n low_o and_o short_a than_o the_o cylinder_n of_o air_n that_o sustain_v it_o which_o appear_v from_o this_o experiment_n to_o be_v true_a see_v by_o the_o pressure_n of_o the_o air_n which_o be_v think_v to_o be_v about_o 7000_o fathom_n high_a 29_o inch_n of_o mercury_n be_v support_v between_o r_o and_o x._o in_o a_o word_n if_o air_n be_v natural_o 14000_o time_n light_a than_o mercury_n which_o be_v very_o probable_a then_o must_v the_o altitude_n of_o it_o common_o call_v the_o atmosphere_n be_v fourteen_o thousand_o time_n nine_o and_o twenty_o inch_n that_o be_v 406000_o or_o of_o foot_n 33833._o experiment_n iii_o figure_n 6._o while_o the_o outward_a and_o inward_a water_n be_v of_o the_o same_o altitude_n withdraw_v the_o inward_a air_n eglantine_n by_o suction_n or_o by_o any_o other_o device_n you_o think_v fit_a and_o you_o will_v find_v the_o water_n rise_v as_o high_a as_o e_z which_o i_o suppose_v to_o be_v 34_o foot_n above_o mgh_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 fk_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 mh_o 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 mh_o 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 mh_o 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'it_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 dehk_v the_o second_o that_o be_v imaginary_a be_v li_z six_o foot_n below_o it_o the_o three_o of_o the_o same_o kind_n be_v mg_n six_o foot_n low_o the_o four_o be_v nfo_n six_o foot_n yet_o low_o the_o last_o and_o low_a be_v abc_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 da_fw-la 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 of_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 ef._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 hg_v 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 ki_v the_o internal_a water_n become_v no_o long_a than_o ki_v 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 no_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 no_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 gh_o 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_o gh_a 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 ki_v in_o this_o case_n the_o water_n within_o it_o become_v no_o long_o then_o ki_v the_o surface_n li_n 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 abc_n then_o in_o the_o next_o no_z and_o more_o in_o this_o then_o in_o the_o surface_n mg_n and_o more_o in_o this_o then_o in_o li._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 instant_o yield_v till_o it_o be_v no_o more_o press_v than_o the_o next_o part_n to_o it_o we_o see_v four_a that_o the_o inequality_n that_o be_v between_o the_o pondus_fw-la and_o the_o potentia_fw-la in_o fluids_n be_v the_o proper_a cause_n of_o the_o motion_n of_o fluids_n for_o when_o you_o endeavour_v to_o make_v a_o surface_n 30_o foot_n deep_a sustain_v a_o pillar_n 40_o foot_n high_a this_o inequality_n be_v the_o true_a cause_n why_o the_o pillar_n subside_v and_o fall_v down_o and_o why_o the_o surface_n yield_v and_o give_v way_n to_o it_o and_o this_o inequality_n be_v the_o true_a cause_n why_o the_o motion_n of_o water_n through_o siphons_n continue_v for_o understand_v this_o you_o must_v conceive_v a_o siphon_n to_o be_v nothing_o else_o but_o a_o crooked_a pipe_n with_o two_o leg_n the_o one_o drown_v among_o water_n the_o other_o hang_v in_o the_o open_a air._n the_o use_n of_o it_o be_v for_o convey_v wine_n or_o water_n from_o one_o vessel_n to_o another_o which_o be_v easy_o do_v by_o suction_n now_o after_o suction_n be_v end_v the_o motion_n of_o the_o water_n continue_v till_o the_o surface_n become_v low_a than_o the_o orifice_n out_o of_o which_o it_o run_v the_o true_a reason_n then_o why_o the_o water_n flow_v out_o be_v the_o inequality_n between_o the_o potentia_fw-la of_o the_o air_n and_o the_o pondus_fw-la of_o the_o water_n the_o pondus_fw-la be_v strong_a than_o the_o potentia_fw-la for_o in_o air_n as_o in_o water_n we_o must_v conceive_v horizontal_n surface_v and_o these_o surface_n to_o be_v endow_v with_o pressure_n and_o force_n as_o be_v the_o surface_v of_o water_n now_o when_o the_o leg_n of_o a_o siphon_n be_v hang_v in_o the_o air_n it_o must_v rest_v upon_o one_o surface_n or_o another_o and_o consequent_o the_o water_n in_o it_o must_v rest_v upon_o the_o same_o surface_n if_o the_o potentia_fw-la of_o the_o surface_n be_v strong_a than_o the_o pondus_fw-la of_o the_o water_n the_o water_n be_v drive_v backward_o which_o always_o come_v to_o pass_v when_o the_o orifice_n be_v high_a than_o the_o surface_n of_o the_o water_n of_o the_o vessel_n among_o which_o the_o other_o leg_n be_v drown_v if_o the_o potentia_fw-la of_o the_o surface_n of_o that_o air_n be_v of_o equal_a power_n and_o strength_n with_o the_o pondus_fw-la of_o the_o water_n the_o water_n go_v neither_o backward_a nor_o forward_o but_o stand_v in_o equilibrio_n this_o happen_v when_o the_o orifice_n be_v neither_o high_o nor_o low_o than_o the_o surface_n of_o the_o water_n in_o the_o vessel_n but_o if_o the_o potentia_fw-la of_o the_o surface_n of_o the_o air_n be_v weak_a than_o the_o pondus_fw-la of_o the_o water_n in_o this_o case_n the_o air_n yield_v and_o suffer_v the_o water_n to_o run_v out_o even_o as_o a_o surface_n 30_o foot_n deep_a yield_v to_o a_o pillar_n of_o water_n 40_o foot_n high_a the_o same_o inequality_n be_v the_o reason_n why_o water_n climb_v up_o the_o pump_n why_o water_n climb_v up_o a_o pipe_n when_o a_o man_n suck_v with_o his_o mouth_n before_o suction_n the_o potentia_n that_o be_v in_o the_o surface_n of_o water_n among_o which_o the_o end_n of_o the_o pipe_n be_v drown_v be_v of_o equal_a force_n with_o the_o pondus_fw-la of_o the_o pillar_n of_o air_n that_o come_v down_o through_o the_o pipe_n or_o pump_n but_o assoon_o as_o a_o man_n begin_v to_o suck_v the_o say_a pillar_n of_o air_n become_v light_a and_o the_o water_n find_v this_o present_o ascend_v the_o same_o be_v the_o reason_n why_o the_o mercury_n fall_v down_o to_o 29_o inch_n in_o the_o baroscope_n and_o no_o further_o for_o as_o long_o as_o the_o pondus_fw-la of_o the_o pillar_n of_o mercury_n exceed_v the_o potentia_fw-la of_o the_o surface_n of_o air_n so_o long_o do_v the_o motion_n continue_v and_o when_o both_o be_v become_v equal_a in_o force_n the_o motion_n cease_v when_o the_o glass-tub_n be_v 40_o inch_n long_o and_o fill_v with_o mercury_n and_o invert_v after_o the_o common_a manner_n you_o be_v endeavour_v as_o it_o be_v to_o cause_v a_o surface_n 29_o inch_n deep_a sustain_v a_o pillar_n 40_o inch_n high_a which_o be_v utter_o impossible_a in_o fluid_n it_o be_v judge_v by_o many_o a_o wonder_n to_o see_v the_o deflux_n of_o the_o mercury_n in_o the_o baroscope_n but_o in_o effect_n there_o be_v no_o more_o cause_n of_o admiration_n in_o it_o than_o to_o see_v the_o cylinder_n of_o water_n grow_v short_a by_o lift_v the_o
orifice_n m_o coming_z up_o from_o d_o some_o inch_n of_o water_n fall_v out_o as_o will_v be_v find_v by_o experience_n suppose_v then_o that_o of_o four_o foot_n six_o inch_n fall_v out_o if_o this_o be_v than_o the_o enclose_a air_n between_o p_o and_o t_o must_v be_v six_o inch_n long_o if_o this_o be_v then_o of_o necessity_n the_o bensil_n of_o it_o must_v be_v proportionable_o remit_v and_o slacken_v whence_o follow_v by_o metaphysical_a necessity_n that_o it_o can_v burden_v the_o water_n pm_n with_o as_o much_o weight_n as_o it_o have_v and_o consequent_o the_o surface_n of_o air_n can_v be_v so_o much_o burden_v it_o must_v then_o be_v no_o more_o burden_v with_o they_o both_o together_o than_o it_o be_v with_o the_o single_a pillar_n of_o air_n yn_n if_o then_o the_o water_n pm_n be_v three_o foot_n and_o a_o half_a the_o weight_n of_o the_o enclose_a air_n tp_n must_v be_v exact_o the_o weight_n of_o thirty_o foot_n of_o water_n and_o a_o half_a from_o this_o experiment_n we_o see_v first_o the_o pressure_n of_o the_o air_n for_o by_o it_o the_o water_n oi_o be_v suspend_v and_o by_o the_o same_o pressure_n be_v the_o water_n pm_n suspend_v we_o see_v second_o that_o in_o air_n there_o be_v a_o power_n of_o dilate_v itself_o and_o that_o this_o dilatation_n never_o happen_v without_o a_o relaxation_n of_o the_o bensil_n we_o see_v three_o that_o one_o fluid_a can_v sustain_v another_o unless_o the_o potentia_fw-la of_o the_o one_o be_v equal_a to_o the_o pondus_fw-la of_o the_o other_o as_o be_v clear_a from_o the_o aërial_a surface_n that_o can_v sustain_v the_o whole_a four_o foot_n of_o water_n but_o suffer_v six_o inch_n of_o it_o to_o fall_v out_o that_o the_o pondus_fw-la of_o the_o rest_n and_o the_o air_n above_o it_o may_v become_v equal_a to_o its_o own_o potentia_fw-la we_o see_v four_a that_o fluid_a body_n have_v not_o only_o a_o power_n of_o press_v downward_o but_o of_o press_v upward_o likewise_o as_o be_v clear_a from_o the_o water_n oi_o that_o be_v suspend_v by_o the_o air_n press_v down_o the_o surface_n of_o water_n hik_fw-mi it_o press_v upward_o also_o while_o it_o support_v the_o water_n pm_n this_o experiment_n also_o answer_v a_o case_n namely_o whether_o or_o not_o it_o be_v always_o needful_a to_o guard_v the_o orifice_n of_o the_o tub_n of_o the_o baroscope_n with_o stagnant_a quicksilver_n i_o say_v then_o it_o be_v not_o always_o needful_a provide_v the_o orifice_n be_v of_o a_o narrow_a diameter_n for_o experience_n tell_v that_o while_o it_o be_v such_o the_o mercury_n will_v subside_o and_o halt_v at_o 29_o inch_n above_o the_o orifice_n though_o no_o stagnant_a mercury_n be_v to_o guard_v in_o make_v this_o trial_n the_o orifice_n must_v be_v no_o wide_o than_o may_v admit_v the_o point_n of_o a_o needle_n or_o suppose_v it_o to_o have_v the_o wideness_n of_o a_o tobacco-pipe_n yet_o will_v the_o mercury_n be_v suspend_v though_o the_o end_n be_v not_o drown_v among_o stagnant_a quicksilver_n even_o as_o the_o water_n pm_n be_v keep_v up_o without_o stagnant_a water_n about_o it_o for_o trial_n of_o this_o you_o must_v first_o let_v the_o end_n of_o the_o pipe_n be_v put_v down_o among_o stagnant_a mercury_n and_o after_o the_o cylinder_n be_v fall_v down_o to_o its_o own_o proper_a altitude_n lift_v up_o the_o pipe_n slow_o till_o the_o orifice_n come_v above_o the_o surface_n and_o you_o will_v find_v provide_v you_o do_v not_o shake_v the_o pipe_n the_o cylinder_n to_o be_v suspend_v after_o the_o same_o manner_n immediate_o by_o the_o air_n as_o the_o water_n pm_n be_v experiment_n vii_o figure_n 10_o 11._o take_v a_o vessel_n of_o any_o quantity_n such_o as_o abcde_v and_o fill_v it_o with_o water_n and_o a_o glass-pipe_n such_o as_o gfd_n of_o 15_o or_o 20_o inch_n long_o of_o any_o wideness_n close_o above_o and_o open_v below_o before_o you_o drown_v the_o open_a end_n among_o the_o water_n hold_v the_o glass_n before_o the_o fire_n till_o it_o be_v pretty_a hot_a and_o have_v put_v it_o down_o you_o will_v see_v the_o water_n begin_v to_o creep_v up_o till_o it_o come_v to_o f_o where_o it_o halt_v the_o question_n now_o be_v what_o be_v the_o reason_n why_o the_o water_n creep_v up_o after_o this_o manner_n 10_o or_o 12_o inch_n above_o the_o surface_n ab_fw-la i_o answer_v the_o heat_n have_v raâ—ified_v the_o air_n within_o and_o by_o this_o mean_n have_v expel_v much_o of_o it_o and_o the_o air_n now_o contract_v itself_o again_o with_o cold_a the_o water_n ascend_v be_v press_v up_o with_o the_o weight_n of_o the_o incumb_a air_n rest_v upon_o the_o surface_n of_o water_n ab_fw-la there_o be_v here_o sure_o a_o inequality_n between_o a_o pondus_fw-la and_o a_o potentia_n that_o must_v be_v the_o cause_n of_o this_o motion_n i_o judge_v then_o the_o inequality_n to_o consist_v between_o the_o weight_n of_o the_o air_n within_o the_o pipe_n and_o the_o surface_n of_o water_n cde_v to_o explicate_v this_o i_o must_v suppose_v the_o pipe_n to_o be_v thrust_v down_o cold_a in_o this_o case_n little_a or_o no_o water_n can_v enter_v the_o orifice_n d._n and_o the_o reason_n be_v because_o the_o pondus_fw-la of_o the_o air_n within_o the_o glass_n be_v equal_a to_o the_o potentia_fw-la of_o the_o surface_n cde_v but_o when_o the_o pipe_n be_v thrust_v down_o hot_a much_o of_o the_o air_n have_v be_v expel_v by_o the_o heat_n and_o now_o begin_v to_o be_v contract_v by_o cold_a the_o pondus_fw-la of_o the_o air_n become_v unequal_a to_o the_o potentia_fw-la of_o the_o surface_n and_o therefore_o this_o be_v the_o strong_a party_n drive_v up_o the_o air_n within_o the_o glass_n till_o by_o this_o ascent_n the_o pondus_fw-la of_o the_o air_n gf_n and_o the_o pondus_fw-la of_o the_o water_n fd_v together_o become_v equal_a to_o the_o potentia_fw-la of_o the_o surface_n cde_v that_o sustain_v they_o for_o a_o second_o trial_n bring_v a_o hot_a coal_n neat_a to_o the_o side_n of_o the_o glass_n between_o g_z and_o f_o and_o you_o will_v find_v the_o water_n to_o creep_v down_o from_o f_o towards_o the_o surface_n ab_fw-la and_o if_o it_o continue_v any_o space_n it_o will_v drive_v down_o the_o whole_a water_n and_o thrust_v it_o out_o at_o d._n to_o explicate_v this_o i_o must_v suppose_v that_o heat_n by_o rarify_n the_o air_n within_o the_o glass_n intend_v and_o increase_v the_o bensil_n of_o it_o and_o the_o bensil_n be_v now_o make_v strong_a there_o must_v arise_v a_o inequality_n between_o the_o pondus_fw-la of_o the_o say_a air_n and_o the_o potentia_fw-la of_o the_o surface_n cde_v the_o air_n then_o be_v the_o strong_a party_n cause_v the_o surface_n to_o yield_v by_o compare_v this_o experiment_n with_o the_o former_a we_o see_v a_o great_a difference_n between_o the_o dilatation_n of_o air_n of_o its_o own_o accord_n and_o by_o constraint_n for_o while_o it_o be_v willing_o expanded_a the_o bensil_n begin_v to_o grow_v slack_a and_o remiss_a and_o lose_v by_o degree_n of_o its_o strength_n even_o as_o the_o spring_n of_o a_o watch_n by_o the_o motion_n of_o the_o wheel_n become_v remiss_a but_o when_o the_o dilatation_n be_v make_v by_o heat_n and_o the_o air_n compel_v to_o expand_v and_o open_v itself_o the_o bensil_n become_v the_o strong_a and_o the_o pressure_n the_o great_a notwithstanding_o though_o the_o bensil_n of_o this_o enclose_a air_n gf_n may_v be_v make_v strong_a by_o heat_n to_o the_o expulsion_n of_o the_o water_n fd_n yet_o if_o this_o rarefaction_n continue_v any_o time_n the_o bensil_n become_v dull_a and_o slack_a and_o the_o reason_n be_v because_o air_n can_v be_v expanded_a and_o open_v to_o any_o quantity_n a_o inch_n can_v be_v dilate_v and_o open_v to_o a_o hundred_o or_o to_o a_o thousand_o neither_o can_v the_o bensil_n of_o it_o be_v intend_v and_o increase_v to_o any_o degree_n u.g._n from_o one_o to_o 20_o 30_o or_o 100_o and_o therefore_o as_o the_o expansion_n grow_v the_o bensil_n must_v at_o length_n slacken_v but_o if_o so_o be_v the_o air_n be_v enclose_v as_o in_o a_o bladder_n knit_v about_o the_o neck_n with_o a_o string_n than_o the_o more_o heat_n the_o more_o bensil_n for_o in_o this_o case_n there_o be_v a_o growth_n of_o pressure_n without_o dilatation_n and_o sometime_o the_o bensil_n may_v be_v so_o intend_v with_o the_o heat_n that_o the_o side_n of_o the_o bladder_n will_v burst_v asunder_o from_o this_o experiment_n we_o see_v first_o a_o confirmation_n of_o the_o 21_o theorem_fw-la namely_o that_o there_o may_v be_v as_o much_o bensil_n and_o pressure_n in_o the_o small_a quantity_n of_o a_o fluid_a as_o in_o the_o great_a as_o be_v clear_a from_o the_o bensil_n of_o the_o air_n gf_n which_o in_o effect_n counterpoise_v the_o weight_n of_o the_o whole_a
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 pondus_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 fg_v 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 fg_v 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 gh_n that_o it_o be_v of_o before_o likewise_o the_o pillar_n ab_fw-la 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 cb_n 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 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chord_n to_o the_o beam_n no_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 fiâ—st_n the_o weight_n of_o the_o water_n before_o the_o stone_n be_v drown_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 kl_n 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 for_o example_n if_o in_o stead_n 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 he_o to_o ab_fw-la the_o water_n of_o the_o vessel_n will_v become_v
represent_v a_o deep_a water_n who_o first_o and_o visible_a surface_n be_v fg._n the_o imaginary_a surface_n be_v elc_a 34_o foot_n below_o it_o adb_n be_v a_o siphon_n work_v below_o this_o water_n with_o mercury_n ael_n be_v a_o vessel_n with_o stagnant_a mercury_n among_o which_o the_o orifice_n a_o be_v drown_v the_o other_o orifice_n b_o exist_v among_o the_o water_n dm_o be_v the_o height_n of_o the_o siphon_n above_o the_o line_n of_o level_n which_o i_o suppose_v be_v 58_o inch_n for_o make_v it_o work_v stop_v the_o two_o orifice_n close_o and_o pour_v in_o as_o much_o mercury_n at_o a_o hole_n make_v at_o d_o as_o will_v fill_v both_o the_o leg_n then_o stop_v the_o say_a hole_n open_v the_o two_o orifice_n a_o and_o b_o and_o you_o will_v find_v the_o liquor_n run_v as_o long_o out_o at_o b_o as_o there_o be_v any_o almost_o in_o the_o vessel_n ael_n for_o evince_v this_o which_o be_v the_o only_a difficulty_n consider_v that_o if_o this_o siphon_n be_v fill_v with_o water_n and_o make_v to_o work_v only_o with_o air_n as_o be_v clear_a from_o daily_a experience_n the_o liquor_n will_v run_v out_o constant_o at_o b._n because_o there_o be_v here_o a_o unequal_a pressure_n the_o surface_n of_o air_n nb_n be_v more_o burden_v than_o the_o surface_n elc_n but_o where_o unequal_a pressure_n be_v in_o fluid_n according_a to_o the_o 12_o theorem_n motion_n must_v follow_v i_o prove_v the_o surface_n nb_n to_o be_v more_o burden_v than_o the_o surface_n elc_n because_o the_o water_n bd_o be_v heavy_a than_o the_o water_n ld_n as_o be_v evident_a to_o the_o eye_n the_o air_n b_o therefore_o sustain_v far_o more_o weight_n than_o the_o air_n el_fw-es mus_fw-la cede_fw-la and_o yield_v next_o there_o be_v here_o a_o pondus_fw-la and_o a_o potentia_fw-la the_o pondus_fw-la be_v the_o water_n ld_n the_o potentia_fw-la by_o which_o it_o be_v counterpoise_v be_v the_o water_n bd_o but_o these_o be_v unequal_a bd_o be_v heavy_a than_o ld_n therefore_o according_a to_o the_o 33_o theorem_fw-la these_o two_o fluid_n can_v cease_v from_o motion_n if_o it_o be_v say_v that_o the_o surface_n nb_n be_v strong_a than_o the_o surface_n elc_n see_v it_o be_v low_a i_o answer_v the_o difference_n be_v so_o unsensible_a that_o they_o may_v be_v judge_v but_o one_o now_o i_o say_v if_o this_o siphon_n work_n in_o air_n with_o water_n it_o must_v likewise_o work_n in_o water_n with_o mercury_n therefore_o this_o siphon_n be_v 34_o foot_n below_o the_o first_o surface_n fg_v the_o liquor_n must_v run_v out_o constant_o at_o b._n because_o there_o be_v here_o a_o unequal_a pressure_n the_o surface_n of_o water_n nb_n be_v more_o burden_v than_o the_o surface_n elc._n though_o there_o be_v more_o weight_n in_o nb_n than_o in_o elc_n because_o it_o be_v low_a yet_o because_o the_o difference_n be_v not_o so_o much_o as_o be_v between_o the_o weight_n of_o bd_o and_o the_o weight_n of_o ld_n it_o prove_v nothing_o note_v here_o that_o so_o long_o as_o d_o be_v within_o 58_o inch_n of_o el_n c_o this_o siphon_n will_v work_v the_o reason_n be_v because_o the_o pressure_n of_o 34_o foot_n of_o water_n with_o the_o pressure_n of_o the_o air_n upon_o fg_v be_v able_a to_o raise_v mercury_n exact_o 58_o inch_n but_o if_o d_o exceed_v that_o height_n no_o art_n will_v make_v the_o liquor_n run_v out_o at_o b._n note_v second_o that_o this_o siphon_n will_v operate_v with_o air_n and_o water_n though_o the_o top_n d_o be_v 34_o foot_n above_o m_n and_o the_o reason_n be_v because_o the_o pressure_n of_o the_o air_n be_v able_a to_o raise_v a_o pillar_n of_o water_n to_o that_o height_n note_n three_o that_o if_o there_o be_v a_o orifice_n open_v at_o c_o upon_o the_o level_a line_n elc_n the_o two_o water_n will_v become_v of_o the_o same_o weight_n the_o one_o not_o be_v able_a to_o move_v the_o other_o if_o you_o bear_v a_o hole_n at_o r_o the_o liquor_n ascend_v from_o r_z to_z d_o and_o go_v down_o from_o d_o to_o a_o and_o so_o the_o motion_n end_v but_o if_o the_o leg_n ad_fw-la be_v six_o time_n wide_a than_o bd_o the_o liquor_n will_v not_o run_v out_o at_o b._n i_o shall_v answer_v this_o in_o the_o close_a from_o this_o experiment_n we_o see_v first_o that_o the_o motion_n of_o fluid_a body_n up_o through_o pump_n and_o siphons_n be_v not_o for_o shune_v vacuity_n but_o because_o they_o be_v press_v up_o violent_o we_o see_v next_o that_o when_o the_o pressure_n be_v uniform_a there_o be_v no_o motion_n in_o fluids_n but_o assoon_o as_o one_o part_n be_v more_o press_v than_o another_o motion_n begin_v because_o this_o siphon_n will_v not_o operate_v if_o the_o orifice_n be_v make_v in_o c_o but_o if_o so_o be_v it_o be_v in_o d_o than_o the_o motion_n begin_v because_o there_o be_v here_o a_o unequal_a pressure_n which_o be_v not_o in_o the_o other_o we_o see_v three_o that_o fluids_n have_v a_o determinate_a sphere_n of_o activity_n to_o which_o they_o be_v able_a to_o press_v and_o no_o further_o because_o this_o water_n be_v not_o able_a to_o press_v mercury_n high_o than_o 58_o inch_n so_o the_o air_n can_v raise_v water_n high_o than_o 34_o foot_n if_o this_o water_n be_v 68_o foot_n deep_a the_o sphere_n of_o its_o activity_n will_v be_v 116_o inch_n we_o see_v four_a that_o in_o fluids_n there_o be_v a_o pondus_fw-la and_o a_o potentia_n and_o that_o the_o inequality_n of_o weight_n between_o the_o two_o be_v the_o only_a cause_n of_o motion_n we_o see_v five_o that_o as_o long_o as_o this_o inequality_n of_o weight_n continue_v as_o long_o continue_v the_o motion_n because_o as_o long_o as_o bd_o be_v heavy_a than_o ld_n the_o motion_n persevere_fw-la we_o see_v sixthly_a the_o possibility_n of_o a_o perpetual_a motion_n in_o fluids_n because_o the_o liquor_n run_v perpetual_o out_o at_o b._n if_o it_o be_v say_v the_o motion_n end_v when_o the_o stagnant_a mercury_n ael_n fail_v i_o answer_v this_o stop_n be_v only_o accidental_a and_o not_o essential_o from_o the_o nature_n of_o fluids_n if_o it_o be_v inquire_v whether_o or_o not_o will_v the_o mercury_n run_v out_o at_o b_o upon_o supposition_n the_o shank_n ld_n be_v twice_o as_o wide_o as_o the_o shank_n bd_o i_o answer_v it_o will_v if_o it_o be_v say_v that_o the_o one_o be_v far_o heavy_a than_o the_o other_o namely_o ld_n than_o db._n i_o answer_v weight_n in_o fluids_n be_v not_o count_v according_a to_o thickness_n but_o according_a to_o altitude_n experiment_n xx._n figure_n 27._o this_o last_o be_v for_o demonstrate_v the_o precise_a and_o just_a weight_n of_o any_o pillar_n of_o air_n water_n mercury_n or_o of_o any_o other_o fluid_a body_n if_o some_o of_o their_o dimension_n be_v but_o once_o know_v ab_fw-la then_o be_v a_o square_a pipe_n 12_o foot_n high_a and_o six_o inch_n in_o wideness_n full_a of_o water_n rest_v upon_o the_o surface_n of_o air_n ac_fw-la and_o eglantine_n be_v a_o square_a pipe_n 12_o foot_n high_a and_o 12_o inch_n wide_a full_a of_o water_n rest_v upon_o the_o surface_n of_o air_n ef._n none_o needs_o to_o doubt_v but_o the_o two_o water_n will_v be_v suspend_v after_o this_o manner_n even_o though_o the_o orifice_n a_o and_o e_o be_v downward_o especial_o if_o they_o be_v guard_v with_o water_n but_o the_o demonstration_n will_v be_v the_o more_o evident_a that_o we_o suppose_v the_o two_o pillar_n of_o water_n to_o be_v suspend_v as_o they_o be_v from_o this_o experiment_n i_o say_v first_o that_o the_o pillar_n of_o air_n cd_o be_v 168_o pound_n weight_n at_o least_o which_o i_o prove_v thus_o the_o water_n ab_fw-la be_v 168_o pound_n therefore_o the_o air_n cd_o must_v be_v as_o much_o i_o prove_v the_o antecedent_n because_o it_o be_v a_o pillar_n of_o water_n 12_o foot_n high_a and_o six_o inch_n thick_a but_o every_o half_a cubical_a foot_n of_o water_n that_o contain_v 216_o inch_n weigh_v seven_o pound_n therefore_o see_v the_o pillar_n be_v 12_o foot_n it_o must_v contain_v 24_o half_a foot_n but_o 24_o time_n 7_o be_v 168._o the_o only_a difficulty_n be_v to_o prove_v the_o connexion_n which_o i_o do_v thus_o from_o the_o seven_o theor._n 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 but_o so_o it_o be_v that_o the_o part_n a_o and_o the_o part_n c_o be_v in_o the_o same_o horizontal_a surface_n therefore_o the_o part_n a_o and_o the_o part_n c_o be_v equal_o press_v but_o if_o the_o part_n a_o and_o the_o part_n c_o be_v equal_o press_v the_o pillar_n of_o air_n cd_o must_v be_v as_o heavy_a as_o the_o pillar_n of_o water_n ab_fw-la i_o say_v second_o that_o the_o pillar_n of_o air_n fh_o weigh_v 672_o pound_n i_o prove_v it_o thus_o
to_o their_o thickness_n but_o only_o according_a to_o their_o altitude_n fig._n â—â—_o pag._n 1â—4_n fig._n 24_o pag._n 152_o fig._n 26._o pag._n 182_o fig._n 27_o pag._n 196_o a_o account_n of_o miscellany_n observation_n late_o make_v by_o the_o author_n of_o the_o forego_n experiment_n observation_n i._n in_o may_n 1669_o there_o be_v need_n of_o a_o new_a sink_n on_o the_o east_n side_n of_o tranent_n for_o win_v of_o coal_n but_o while_o the_o coal-hewers_a be_v in_o dig_v down_o and_o have_v come_v the_o deepness_n of_o 13_o or_o 14_o fathom_n they_o be_v stop_v from_o work_v by_o damp_n or_o ill_a air_n that_o flow_v out_o plentiful_o from_o the_o side_n of_o the_o sink_n wherein_o there_o be_v a_o great_a number_n of_o cutter_n or_o rift_n out_o of_o which_o that_o ill_a air_n come_v to_o try_v the_o nature_n and_o power_n of_o damp_n i_o take_v a_o dog_n and_o fasten_v he_o in_o a_o bucket_n with_o a_o small_a roap_n that_o he_o may_v not_o leap_v over_o and_o when_o he_o 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ship_n under_o sail_n it_o must_v receive_v two_o distinct_a impulse_n one_o from_o the_o hand_n whereby_o it_o be_v carry_v upward_o the_o other_o from_o the_o ship_n whereby_o it_o be_v carry_v forward_o by_o this_o mean_n the_o stone_n in_o go_v up_o and_o come_v down_o can_v describe_v a_o perpendicular_a but_o a_o crooked_a line_n either_o a_o parabola_fw-la or_o a_o line_n very_o like_a unto_o it_o neither_o can_v it_o describe_v a_o perpendicular_a line_n in_o come_v down_o from_o the_o top_n of_o the_o mast_n though_o in_o appearance_n it_o seem_v to_o do_v so_o but_o a_o crooked_a one_o which_o in_o effect_n must_v be_v the_o half_a of_o that_o which_o it_o describe_v in_o go_v up_o and_o come_v down_o for_o this_o same_o cause_n a_o stone_n throw_v horizontal_o or_o towards_o the_o brink_n of_o the_o water_n must_v describe_v a_o crooked_a line_n also_o and_o a_o pistol_n bullet_n shot_n while_o a_o man_n be_v ride_v at_o a_o full_a career_n must_v describe_v a_o line_n of_o 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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 straight_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 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