they_o allege_v that_o the_o intendment_n thereof_o at_o first_o be_v no_o more_o but_o this_o that_o the_o tendency_n of_o a_o heavy_a body_n be_v to_o the_o earth_n centre_n when_o there_o it_o be_v its_o heaviness_n if_o not_o otherwise_o press_v will_v not_o endeavour_v any_o further_a motion_n for_o to_o move_v further_o be_v to_o move_v from_o the_o centre_n and_o according_o if_o the_o tendency_n of_o any_o other_o body_n be_v to_o a_o certain_a place_n as_o its_o term_n when_o there_o it_o be_v that_o principle_n will_v not_o endeavour_v a_o motion_n from_o thence_o for_o so_o to_o do_v be_v to_o move_v contrary_a to_o its_o own_o nature_n and_o if_o it_o be_v carry_v further_o it_o must_v be_v from_o some_o other_o cause_n as_o when_o a_o pendulum_n swing_v beyond_o the_o perpendicular_a it_o be_v not_o from_o weight_n simple_o consider_v which_o will_v there_o have_v stay_v but_o from_o a_o impetus_fw-la imnpress_v by_o a_o precedent_a motion_n and_o thus_o far_o that_o principle_n be_v just_a and_o good_a but_o the_o objection_n pervert_v it_o to_o a_o sense_n never_o intend_v by_o the_o first_o introducer_n next_o i_o will_v ask_v what_o be_v mean_v by_o the_o water_n own_o place_n and_o particular_o whether_o water_n in_o a_o pond_n artificial_o contrive_v on_o the_o top_n of_o a_o tower_n be_v in_o its_o own_o place_n if_o so_o then_o though_o a_o hole_n be_v in_o the_o bottom_n it_o ought_v not_o to_o run_v out_o if_o not_o in_o its_o own_o place_n than_o the_o reason_n fail_v for_o even_o there_o a_o diver_n shall_v no_o more_o feel_v the_o weight_n of_o the_o water_n than_o if_o in_o the_o thames_n so_o that_o it_o be_v not_o its_o be_v in_o its_o own_o place_n but_o somewhat_o else_o that_o make_v the_o weight_n not_o to_o be_v feel_v to_o avoid_v this_o therefore_o and_o the_o like_a instance_n they_o now_o explain_v their_o meaning_n to_o be_v that_o it_o do_v not_o gravitate_fw-la on_o any_o thing_n which_o be_v not_o specifical_o light_a than_o itself_o and_o to_o this_o explication_n it_o be_v that_o we_o be_v to_o apply_v our_o answer_n but_o neither_o will_v this_o hold_v for_o it_o be_v manifest_a to_o use_v a_o ordinary_a instance_n that_o a_o vessel_n pierce_v near_o the_o bottom_n in_o fig._n 12_o 13._o will_v run_v with_o a_o full_a and_o strong_a stream_n than_o if_o at_o the_o middle_n or_o near_o the_o top_n and_o more_o when_o it_o be_v full_a than_o when_o half_o out_o or_o almost_o empty_a which_o argue_v a_o pressure_n of_o the_o upper_a part_n upon_o those_o near_o the_o vent_n and_o to_o say_v they_o press_v not_o on_o the_o intermediate_v part_n but_o only_o on_o the_o air_n without_o be_v a_o mere_a evasion_n for_o the_o remote_a part_n of_o the_o water_n can_v press_v that_o air_n but_o by_o press_v that_o which_o be_v between_o like_v as_o in_o a_o crowd_n he_o that_o be_v at_o a_o distance_n can_v thrust_v he_o that_o be_v at_o the_o door_n but_o by_o thrust_v those_o that_o be_v between_o and_o with_o a_o pole_n we_o can_v thrust_v that_o at_o the_o end_n of_o it_o but_o by_o thrust_v the_o pole_n nor_o with_o a_o rope_n draw_v that_o which_o be_v fasten_v to_o it_o but_o by_o draw_v the_o rope_n where_o yet_o there_o be_v a_o signal_n difference_n between_o trusion_n and_o traction_n in_o trusion_n it_o suffice_v that_o the_o thing_n be_v contiguous_a though_o there_o be_v no_o connexion_n but_o in_o traction_n there_o must_v be_v a_o connexion_n and_o that_o strong_a enough_o else_o the_o string_n will_v break_v and_o the_o weight_n not_o follow_v and_o though_o a_o heap_n of_o sand_n will_v suffice_v to_o press_v down_o the_o scale_n yet_o a_o rope_n of_o sand_n will_v not_o serve_v to_o draw_v it_o up_o and_o therefore_o mr._n line_n be_v funiculus_fw-la in_o his_o explication_n of_o the_o torricellian_a experiment_n must_v have_v somewhat_o of_o texture_n as_o well_o as_o contiguity_n to_o give_v it_o strength_n without_o which_o it_o will_v not_o be_v able_a to_o sustain_v the_o weight_n of_o the_o suspend_v quicksilver_n but_o certain_o if_o the_o part_n of_o a_o fluid_a be_v able_a to_o draw_v one_o another_o much_o more_o will_v they_o be_v able_a to_o thrust_v one_o another_o that_o be_v the_o one_o to_o gravitate_fw-la upon_o the_o other_o it_o be_v therefore_o much_o more_o conceivable_a in_o the_o invert_v syphon_n how_o the_o water_n at_o a_o fig._n 9_o shall_v thrust_v up_o that_o at_o b_o than_o how_o the_o air_n at_o e_z ascend_v shall_v draw_v up_o the_o water_n at_o b_o and_o thereby_o draw_v down_o that_o at_o a._n for_o in_o the_o first_o case_n there_o needs_o only_o a_o contiguity_n in_o the_o latter_a there_o must_v be_v a_o connexion_n of_o all_o the_o part_n and_o therefore_o if_o we_o shall_v allow_v that_o mr._n line_n be_v funiculus_fw-la or_o rope_n of_o sands_n if_o grant_v will_v equal_o solve_v the_o phaenomenon_n by_o way_n of_o traction_n yet_o since_o the_o hypothesis_n of_o trusion_n as_o be_v acknowledge_v will_v do_v it_o also_o it_o be_v much_o rather_o to_o be_v choose_v than_o that_o of_o traction_n by_o a_o rope_n of_o sands_z shall_v i_o call_v it_o or_o a_o rope_n of_o nothing_o but_o further_a it_o be_v confess_v by_o a_o very_a learned_a author_n the_o author_n of_o two_o treatise_n the_o one_o entitle_v a_o essay_n touch_v the_o gravitation_n or_o non-gravitation_a of_o fluid_a body_n the_o other_o observation_n touch_v the_o torricellian_a experiment_n who_o be_v please_v to_o conceal_v his_o name_n that_o defend_v the_o funiculus_fw-la and_o deny_v our_o hypothesis_n that_o not_o only_a water_n but_o even_o oil_n in_o the_o pipe_n a_o fig._n 5._o will_v force_v up_o the_o water_n at_o b_o and_o if_o the_o pipe_n be_v empty_a oil_n be_v pour_v on_o b_o it_o will_v force_v up_o water_n into_o the_o pipe_n a_o not_o to_o a_o level_n but_o to_o a_o equipois_n that_o be_v as_o his_o own_o word_n be_v to_o such_o a_o proportion_n of_o height_n in_o the_o tube_n as_o will_v countervail_v the_o weight_n of_o a_o like_o cylinder_n of_o oil_n and_o give_v the_o same_o reason_n for_o it_o that_o we_o do_v the_o disparity_n of_o pressure_n cause_v motion_n or_o elevation_n of_o the_o water_n in_o that_o part_n nor_o equal_o press_v so_o that_o here_o a_o light_a body_n do_v gravitate_fw-la on_o a_o heavy_a oil_n upon_o water_n and_o that_o not_o only_a ad_fw-la pondus_fw-la but_o ad_fw-la motum_fw-la as_o himself_o admit_v that_o be_v in_o our_o language_n it_o do_v not_o only_a gravitate_fw-la but_o pregravitate_fw-la not_o only_o weigh_v but_o outweigh_v so_o that_o here_o the_o notion_n of_o a_o fluid_n not_o gravitate_v on_o a_o heavy_a than_o itself_o or_o one_o as_o heavy_a be_v quite_o destroy_v and_o it_o be_v manifest_a also_o that_o not_o the_o level_n but_o the_o equipois_n be_v that_o which_o be_v here_o attend_v for_o the_o surface_n of_o the_o oil_n without_o the_o pipe_n because_o specifical_o light_a will_v be_v somewhat_o high_a than_o that_o of_o the_o water_n within_o it_o and_o just_o so_o much_o as_o to_o make_v up_o the_o equipois_n and_o contrariwise_a if_o that_o in_o the_o pipe_n be_v oil_n and_o that_o without_o it_o be_v water_n that_o within_o the_o pipe_n will_v be_v high_o and_o in_o such_o proportion_n high_o the_o same_o will_v be_v if_o that_o at_o b_o be_v stagnant_a quicksilver_n and_o that_o in_o the_o pipe_n a_o be_v oil_n or_o water_n or_o some_o light_a fluid_n a_o pound_n of_o water_n pour_v into_o the_o pipe_n will_v itself_o stand_v high_a because_o it_o will_v take_v up_o more_o room_n but_o will_v raise_v the_o stagnant_a quicksilver_n just_a as_o high_a as_o if_o a_o pound_n of_o quicksilver_n have_v be_v pour_v on_o without_o any_o respect_n have_v to_o the_o specific_a gravity_n or_o levity_n and_o a_o ship_n lade_v fig._n 8._o will_v draw_v just_a as_o much_o water_n if_o lade_v with_o so_o many_o hundred_o weight_n of_o timber_n as_o with_o so_o many_o hundred_o weight_n of_o lead_n though_o that_o be_v light_a and_o this_o heavy_a than_o a_o like_a quantity_n of_o water_n and_o a_o piece_n of_o wood_n fig._n 7._o though_o light_a than_o water_n yet_o do_v not_o float_v on_o the_o very_a top_n but_o sink_v so_o far_o into_o the_o water_n till_o it_o possess_v the_o place_n of_o so_o much_o water_n as_o be_v of_o equal_a weight_n with_o itself_o that_o be_v till_o the_o horizontal_n plain_n pass_v by_o the_o bottom_n of_o the_o wood_n be_v in_o all_o place_n equal_o press_v partly_o with_o wood_n partly_o with_o water_n which_o be_v know_v experiment_n and_o confess_v on_o all_o hand_n do_v quite_o destroy_v the_o notion_n of_o non-gravitation_a of_o fluid_n on_o what_o be_v not_o specifical_o light_a than_o
body_n it_o be_v that_o i_o intend_v principal_o to_o speak_v of_o which_o the_o first_o and_o great_a phoenomenon_n be_v this_o that_o they_o will_v if_o undisturbed_a reduce_v themselves_o by_o their_o own_o weight_n to_o a_o level_n that_o be_v to_o a_o horizontal_n plain_n or_o what_o as_o to_o sense_n be_v such_o and_o will_v so_o continue_v if_o either_o not_o press_v at_o all_o or_o equal_o press_v on_o all_o part_n as_o if_o the_o surface_n by_o any_o mean_n be_v undulous_a as_o abab_v in_o fig._n 2._o the_o prominence_n at_o a_o will_v sink_v to_o fill_v up_o the_o cavity_n at_o b_o till_o all_o come_v to_o the_o level_n of_o le._n and_o this_o they_o will_v do_v partly_o by_o spread_v abroad_o and_o flow_v into_o those_o cavity_n as_o low_a place_n and_o partly_o the_o whole_a be_v fluid_a by_o press_v down_o what_o be_v under_o a_o and_o press_v up_o what_o be_v under_o b_o in_o fig._n 3._o for_o though_o only_a the_o former_a of_o these_o will_v happen_v in_o case_n all_o under_o le_z in_o fig._n 4._o be_v a_o firm_a solid_a surface_n like_a as_o when_o water_n overflow_v the_o dry_a ground_n and_o fill_v up_o all_o the_o furrow_n and_o only_o the_o latter_a in_o case_n such_o prominence_n whether_o one_o or_o more_o be_v contain_v within_o solid_a pipe_n in_o fig._n 5._o so_o as_o that_o they_o can_v not_o flow_v lateral_o into_o the_o adjacent_a cavity_n yet_o in_o the_o present_a case_n where_o both_o occasion_n happen_v both_o cause_n will_v operate_v for_o nature_n do_v not_o work_v by_o election_n but_o ad_fw-la ultimum_fw-la virium_fw-la and_o all_o the_o way_n it_o can_v where_o one_o do_v not_o oppose_v the_o other_o and_o like_v as_o if_o a_o vessel_n have_v two_o hole_n the_o one_o at_o the_o side_n the_o other_o at_o the_o bottom_n the_o water_n will_v run_v out_o at_o both_o so_o the_o prominence_n at_o a_o be_v not_o hinder_v of_o either_o will_v partly_o by_o lateral_a fluxion_n partly_o by_o direct_a depression_n fill_v up_o the_o cavity_n of_o b_o in_o fig._n 5._o it_o be_v true_a that_o a_o solid_a body_n have_v opportunity_n of_o both_o because_o by_o reason_n of_o the_o coherence_n of_o part_n it_o can_v move_v but_o one_o way_n will_v move_v that_o way_n only_o which_o be_v most_o declive_a but_o a_o fluid_a body_n be_v partible_a in_o every_o point_n divide_v itself_o every_o way_n as_o there_o be_v opportunity_n now_o such_o fluid_a body_n be_v thus_o reduce_v to_o a_o level_n if_o undisturbed_a it_o will_v so_o remain_v in_o fig._n 6._o for_o there_o be_v now_o no_o prominence_n as_o at_o a_o in_o fig._n 2._o to_o sink_v or_o flow_v down_o nor_o cavity_n as_o at_o b_o to_o receive_v they_o nor_o be_v any_o part_n of_o it_o more_o press_v than_o other_o whereby_o that_o shall_v sink_v or_o this_o rise_n but_o if_o at_o some_o part_n as_o at_z d_o in_o fig._n 7._o by_o weight_n or_o other_o force_n it_o be_v press_v but_o not_o in_o other_o or_o more_o at_o d_o than_o at_o other_o it_o will_v at_o d_o subside_n or_o be_v depress_v and_o rise_v elsewhere_o in_o fig._n 8._o and_o what_o be_v thus_o show_v of_o the_o level_v le_z hold_v equal_o of_o any_o other_o level_n as_o f_o g._n within_o the_o fluid_a at_o what_o depth_n soever_o in_o fig._n 8._o if_o all_o part_n of_o it_o be_v equal_o press_v it_o keep_v its_o level_n but_o if_o some_o part_n of_o it_o be_v more_o than_o other_o those_o will_v subside_o and_o these_o rise_n because_o the_o weak_a force_n must_v give_v way_n to_o the_o strong_a the_o like_a happen_v in_o a_o syphon_n invert_v in_o fig._n 9_o where_o if_o the_o water_n be_v high_o in_o the_o one_o leg_n at_o a_o than_o in_o the_o other_o b_o that_o will_v sink_v and_o this_o rise_v till_o they_o come_v to_o a_o level_n at_o le_z and_o when_o so_o it_o will_v there_o rest_v if_o there_o be_v no_o other_o force_n to_o put_v it_o in_o motion_n so_o in_o a_o ewer_n fig._n 10._o or_o other_o vessel_n with_o a_o nose_n the_o water_n in_o the_o vessel_n if_o high_o will_v sink_v itself_o till_o that_o in_o the_o nose_n be_v raise_v to_o the_o same_o height_n if_o that_o in_o the_o nose_n be_v high_o this_o will_v sink_v and_o that_o rise_v till_o they_o come_v to_o a_o level_n at_o le._n the_o reason_n of_o it_o if_o we_o do_v not_o study_v to_o perplex_v the_o phaenomenon_n be_v very_o evident_a because_o while_o the_o fluid_a suppose_v it_o uniform_a stand_v at_o the_o level_v le_z no_o part_n of_o the_o same_o horizontal_n plain_n at_o what_o depth_n soever_o be_v more_o press_v than_o other_o whereby_o it_o shall_v be_v enable_v to_o thrust_v any_o other_o out_o of_o place_n upon_o the_o same_o account_n that_o of_o two_o scale_n equal_o charge_v neither_o can_v descend_v or_o force_v up_o the_o other_o but_o do_v mutual_o sustain_v each_o other_o in_o equipois_n and_o be_v at_o rest_n for_o though_o both_o do_v ponderate_a yet_o neither_o do_v preponderate_a and_o no_o power_n be_v able_a to_o over-bear_a another_o power_n unless_o strong_a than_o it_o but_o in_o case_n the_o fluid_n be_v high_o at_o a_o than_o at_o b_o the_o part_n under_o a_o be_v more_o press_v than_o those_o under_o b_o and_o therefore_o those_o thrust_v these_o away_o on_o the_o same_o account_n that_o if_o the_o scale_n a_o be_v heavy_a charge_v than_o b_o though_o both_o press_v downward_o yet_o the_o heavy_a prevail_v and_o force_v up_o the_o light_a for_o of_o contrary_a power_n the_o great_a always_o over-power_n the_o lesser_a it_o will_v yet_o be_v not_o amiss_o that_o i_o may_v not_o in_o the_o sequel_n be_v mistake_v to_o give_v notice_n by_o the_o way_n that_o what_o i_o have_v say_v of_o this_o level_n in_o heavy_a fluide_n be_v not_o so_o to_o be_v understand_v as_o if_o this_o level_n be_v in_o all_o case_n mathematical_o exact_a for_o though_o it_o ought_v so_o to_o be_v if_o nothing_o else_o do_v intervene_v than_o what_o we_o have_v hitherto_o take_v into_o consideration_n yet_o many_o time_n some_o little_a accident_n do_v disturb_v it_o as_o when_o a_o drop_n of_o water_n on_o a_o dry_a board_n keep_v a_o convex_a figure_n either_o because_o of_o some_o little_a viscosity_n therein_o or_o as_o shun_v the_o contact_n of_o that_o dry_a surface_n and_o quicksilver_n in_o a_o glass-pipe_n or_o like_o vessel_n will_v have_v a_o visible_o convex_v surface_n as_o shun_v the_o contact_n of_o the_o glass_n and_o the_o like_a will_v happen_v in_o water_n if_o the_o glass_n be_v greasy_a and_o contrariwise_a the_o surface_n of_o water_n in_o such_o a_o clean_a vessel_n will_v be_v rather_o concave_a and_o so_o i_o suppose_v will_v be_v the_o surface_n of_o quicksilver_n if_o the_o glass_n be_v guild_v within_o because_o of_o its_o easy_a application_n of_o itself_o too_o gold_n it_o be_v observable_a also_o that_o water_n in_o very_o slender_a pipe_n will_v rise_v visible_o high_o than_o the_o surface_n of_o that_o in_o the_o broad_a vessel_n because_o the_o air_n can_v more_o convenient_o apply_v its_o pressure_n on_o that_o broad_a vessel_n than_o in_o the_o slender_a pipe_n and_o fluide_n will_v many_o time_n upon_o motion_n retain_v a_o undulation_n or_o dance_v up_o and_o down_o sometime_o above_o sometime_o below_o the_o true_a level_n for_o a_o considerable_a time_n before_o they_o rest_v upon_o a_o like_a reason_n that_o a_o pendulum_n will_v swing_n back_o and_o forth_o beyond_o the_o perpendicular_a on_o either_o side_n not_o by_o its_o weight_n simple_o consider_v which_o will_v rest_v precise_o at_o the_o perpendicular_a without_o rise_v on_o the_o other_o side_n but_o by_o reason_n of_o its_o contract_a impetus_fw-la but_o these_o and_o other_o little_a inequality_n which_o be_v to_o be_v account_v for_o from_o divers_a accident_n we_o here_o neglect_v and_o consider_v only_o what_o will_v be_v the_o result_n of_o the_o gravity_n and_o fluidity_n free_v from_o such_o other_o accident_n too_o copious_a here_o to_o be_v insist_v on_o our_o meaning_n therefore_o be_v that_o set_v aside_o other_o accident_n a_o fluid_a body_n will_n by_o its_o gravity_n reduce_v itself_o to_o such_o a_o level_n and_o be_v so_o reduce_v will_v so_o by_o counterpoise_n preserve_v itself_o if_o not_o disturb_v by_o other_o force_n but_o it_o be_v here_o object_v that_o water_n upon_o water_n do_v not_o gravitate_fw-la and_o the_o like_a of_o other_o not-springy_a fluide_n because_o a_o element_n say_v they_o do_v not_o gravitate_fw-la in_o its_o own_o place_n and_o for_o instance_n they_o tell_v we_o that_o a_o man_n under_o water_n feel_v not_o the_o weight_n of_o the_o water_n over_o he_o in_o fig._n 11._o before_o i_o direct_o answer_v this_o objection_n i_o have_v this_o to_o say_v to_o the_o principle_n
as_o water_n and_o from_o he_o the_o torricellian_a experiment_n take_v its_o name_n the_o experiment_n be_v thus_o administer_v in_o fig._n 36._o a_o glass-pipe_n close_v at_o the_o bottom_n be_v fill_v with_o quicksilver_n and_o then_o invert_v the_o orifice_n be_v stop_v with_o the_o finger_n or_o otherwise_o till_o it_o be_v immerse_v in_o a_o vessel_n of_o stagnant_a quicksilver_n and_o then_o open_v if_o the_o height_n of_o the_o pipe_n above_o the_o stagnant_a quicksilver_n be_v not_o more_o than_o 29_o inch_n or_o thereabouts_o it_o will_v remain_v full_a the_o cause_n hereof_o say_v they_o be_v ne_o detur_fw-la vacuum_n for_o if_o the_o quicksilver_n shall_v sink_v there_o be_v no_o way_n for_o the_o air_n to_o enter_v there_o will_v ensue_v a_o vacuum_n which_o nature_n abhor_v the_o cause_n say_v we_o be_v because_o the_o weight_n of_o the_o incumbent_a air_n on_o a_o which_o we_o have_v already_o prove_v to_o be_v heavy_a be_v equivalent_a to_o the_o weight_n of_o 29_o inch_n of_o quicksilver_n which_o therefore_o be_v defend_v by_o the_o close_a glass_n which_o we_o suppose_v otherwise_o to_o be_v hold_v firm_a from_o any_o other_o pressure_n than_o its_o own_o weight_n be_v by_o that_o counterpressure_n sustain_v but_o further_o if_o the_o height_n of_o the_o pipe_n above_o the_o stagnant_a quicksilver_n be_v more_o than_o about_o 29_o inch_n that_o in_o the_o pipe_n will_v sink_v to_o that_o height_n as_o at_o e_o leaving_z space_n above_o it_o in_o the_o glass_n void_a of_o quicksilver_n but_o whether_o fill_v by_o any_o other_o imperceptible_a fluid_n we_o dispute_v not_o the_o reason_n why_o it_o so_o sink_v our_o ancestor_n have_v not_o assign_v because_o they_o be_v not_o at_o all_o aware_a of_o this_o phaenomenon_n but_o thought_n that_o ne_fw-la detur_fw-la vacuum_fw-la it_o will_v remain_v full_a whatever_o the_o height_n of_o the_o tube_n be_v some_o modern_n with_o des_n cartes_n that_o they_o may_v avoid_v a_o vacuum_n do_v imagine_v that_o a_o materia_fw-la subtilis_fw-la of_o which_o no_o sense_n can_v make_v any_o dicovery_n pierce_v the_o pore_n of_o the_o glass_n supply_v that_o place_n but_o if_o it_o will_v so_o supply_v the_o place_n above_o e_o and_o give_v the_o quicksilver_n leave_v to_o sink_v so_o low_a why_o it_o may_v not_o as_o well_o comein_a to_o relieve_v the_o rest_n and_o so_o give_v it_o leave_v to_o sink_v to_o a_o i_o do_v not_o find_v other_o with_o linus_n imagine_v that_o the_o weight_n of_o 29_o inch_n of_o quicksilver_n do_v stretch_v some_o part_n of_o its_o upper_a surface_n into_o a_o subtle_a matter_n very_o thin_a yet_o so_o as_o to_o fill_v that_o seem_o void_a space_n but_o because_o a_o less_o weight_n will_v not_o serve_v so_o to_o stretch_v it_o it_o fall_v no_o low_o which_o stretch_v matter_n like_o a_o funiculus_fw-la hold_v up_o the_o rest_n ne_fw-la detur_fw-la vacuum_fw-la but_o why_o this_o weight_n shall_v stretch_v some_o very_a small_a part_n of_o it_o so_o prodigious_o thin_a and_o not_o stretch_v the_o rest_n at_o all_o rather_o than_o give_v some_o moderate_a tensure_n to_o the_o whole_a they_o do_v not_o that_o i_o remember_v assign_v any_o reason_n other_o suppose_v this_o funiculus_fw-la to_o be_v make_v not_o by_o stretch_v the_o upper_a part_n of_o the_o quicksilver_n but_o by_o squeeze_v out_o the_o more_o subtle_a part_n from_o the_o whole_a body_n of_o it_o which_o like_o a_o vapour_n fill_v that_o seem_o void_a space_n but_o that_o less_o than_o such_o a_o weight_n will_v not_o so_o squeeze_v it_o and_o therefore_o it_o fall_v no_o low_a but_o why_o it_o shall_v so_o fall_v out_o that_o all_o liquor_n whatever_o of_o never_o so_o different_a texture_n shall_v by_o the_o same_o weight_n be_v thus_o dissolvable_a and_o not_o rather_o some_o require_v a_o great_a some_o a_o lesser_a weight_n thus_o to_o resolve_v or_o squeeze_v they_o they_o assign_v no_o reason_n yet_o we_o find_v so_o it_o be_v since_o that_o the_o light_a the_o liquor_n be_v the_o great_a height_n must_v be_v allow_v and_o in_o such_o proportion_n great_a to_o make_v up_o a_o equivalent_a weight_n but_o the_o cause_n be_v say_v we_o and_o it_o seem_v the_o most_o simple_a and_o unforced_a account_n because_o the_o counterpressure_n of_o the_o air_n be_v equivalent_a to_o that_o of_o about_o 29_o inch_n so_o much_o it_o be_v able_a to_o sustain_v but_o no_o more_o and_o just_o so_o much_o weight_n it_o will_v sustain_v whatever_o the_o liquor_n be_v whether_o specifical_o light_a or_o heavy_a and_o whether_o of_o a_o more_o firm_a or_o a_o loser_n texture_n and_o therefore_o to_o such_o a_o height_n it_o sink_v but_o no_o low_o and_o have_v the_o ancient_n be_v aware_a of_o what_o we_o find_v that_o the_o air_n have_v a_o positive_a gravity_n and_o consequent_o though_o it_o be_v but_o small_a in_o proportion_n to_o that_o of_o other_o body_n yet_o a_o great_a height_n of_o air_n may_v countervail_v a_o lesser_a height_n of_o a_o heavy_a liquor_n like_a as_o we_o see_v that_o a_o great_a height_n of_o water_n will_v countervail_v a_o lesser_a height_n of_o quicksilver_n they_o will_v not_o i_o presume_v have_v trouble_v themselves_o with_o a_o fuga_fw-la vacui_fw-la but_o say_v roundly_o that_o the_o weight_n of_o the_o air_n at_o its_o full_a height_n be_v equivalent_a to_o that_o of_o water_n at_o the_o height_n of_o about_o 34_o foot_n and_o of_o quicksilver_n at_o about_o 29_o inch_n and_o proportionable_o of_o other_o fluid_n and_o consequent_o when_o in_o the_o pump_n or_o syringe_n d_o by_z the_o embolus_fw-la or_o sucker_n be_v defend_v from_o the_o air_n pressure_n but_o a_o expose_v to_o it_o in_o fig._n 34._o this_o pressure_n on_o a_o will_v raise_v over_o b_o so_o much_o weight_n of_o water_n quicksilver_n or_o other_o fluid_a as_o be_v equivalent_a to_o that_o pressure_n in_o the_o same_o manner_n as_o if_o a_o and_o e_z were_z equal_o expose_v to_o the_o air_n pressure_n a_o quantity_n of_o oil_n pour_v on_o a_o will_v have_v raise_v a_o weight_n of_o water_n or_o quicksilver_n equivalent_a thereunto_o the_o like_a account_n we_o give_v of_o the_o syphon_n the_o pressure_n on_o a_o in_o fig._n 35._o will_v raise_v the_o fluid_a to_o the_o height_n of_o b_o if_o not_o great_a than_o what_o be_v before_o describe_v and_o from_o thence_o to_o o_o it_o fall_v by_o its_o own_o weight_n yet_o so_o that_o if_o o_o be_v high_a than_o a_o the_o air_n pressure_n at_o o_o will_v thrust_v up_o o_o to_o b_o suppose_v the_o pipe_n not_o so_o big_a as_o that_o the_o air_n can_v convenient_o pass_v by_o the_o liquor_n into_o the_o pipe_n and_o it_o will_v fall_v down_o to_o a_o by_o its_o own_o weight_n for_o now_o boy_n will_v less_o gravitate_fw-la than_o basilius_n while_o yet_o the_o air_n pressure_n will_v be_v much_o the_o same_o on_o both_o there_o be_v yet_o a_o considerable_a objection_n to_o be_v remove_v viz._n that_o air_n in_o a_o close_a vessel_n though_o of_o no_o great_a height_n press_v on_o a_o the_o surface_n of_o the_o stagnant_a quicksilver_n fig._n 37._o will_v sustain_v as_o high_a a_o pillar_n thereof_o in_o a_o close_a tube_n suppose_v ae_n as_o if_o a_o be_v expose_v to_o the_o open_a air_n whereas_o yet_o the_o weight_n of_o ad_fw-la within_o the_o vessel_n defend_v by_o the_o vessel_n from_o the_o pressure_n of_o the_o incumbent_a air_n can_v be_v of_o equal_a weight_n as_o if_o it_o have_v the_o whole_a height_n of_o the_o atmosphere_n but_o the_o reason_n of_o this_o be_v from_o the_o air_n spring_n which_o be_v always_o equivalent_a to_o the_o pressure_n lie_v upon_o it_o and_o consequent_o the_o spring_n of_o the_o air_n in_o its_o ordinary_a constitution_n with_o we_o must_v be_v equivalent_a to_o the_o weight_n of_o the_o incumbent_n air._n for_o if_o it_o be_v less_o the_o air_n incumbent_n will_v yet_o press_v it_o close_o if_o it_o be_v more_o the_o spring_n will_v relax_v itself_o by_o thrust_v away_o what_o press_v it_o which_o be_v so_o the_o air_n include_v with_o such_o a_o spring_n must_v therefore_o press_v with_o as_o great_a a_o strength_n as_o be_v equivalent_a to_o such_o a_o weight_n like_o as_o in_o other_o spring_n if_o acb_n in_o fig._n 38._o be_v press_v by_o the_o weight_n d_o to_o such_o a_o tensure_n as_o to_o bear_v it_o and_o then_o this_o spring_n so_o remain_v the_o weight_n be_v take_v away_o and_o our_o hand_n put_v in_o the_o place_n of_o it_o it_o will_v press_v as_o hard_o against_o the_o hand_n as_o before_o it_o do_v to_o sustain_v the_o weight_n that_o be_v with_o a_o force_n equal_a to_o that_o of_o the_o weight_n it_o sustain_v and_o if_o thus_o bow_v it_o be_v put_v in_o a_o vessel_n in_o fig._n 39_o it_o will_v with_o just_a the_o same_o force_n press_v against_o the_o side_n of_o it_o and_o just_o so_o it_o be_v in_o the_o present_a case_n where_o the_o air_n so_o include_v do_v press_v by_o its_o spring_n just_a with_o the_o same_o force_v as_o be_v that_o of_o the_o incumbent_a air_n which_o give_v it_o this_o tensure_n it_o be_v yet_o the_o more_o evident_a because_o if_o by_o the_o air-pump_n part_v of_o this_o air_n be_v pump_v out_o and_o thereby_o the_o rest_n less_o compress_v the_o quicksilver_n in_o the_o tube_n in_o fig._n 37._o will_v sink_v from_o e_o to_o a_o low_a station_n as_o to_o f_o or_o g_o and_o so_o low_o and_o low_o as_o more_o and_o more_o air_n be_v pump_v out_o and_o the_o spring_n thereby_o relax_v that_o be_v as_o the_o spring_n grow_v weak_a so_o it_o be_v less_o able_a to_o support_v the_o weight_n and_o this_o quite_o destroy_v the_o evasion_n but_o now_o mention_v that_o the_o seem_a void_a space_n be_v fill_v by_o a_o thin_a substance_n which_o can_v by_o the_o weight_n of_o 29_o inch_n of_o quicksilver_n or_o 34_o foot_n of_o water_n but_o not_o by_o less_o be_v stretch_v to_o that_o fineness_n and_o that_o therefore_o it_o will_v sink_v to_o that_o height_n but_o not_o low_o for_o by_o this_o last_o experiment_n when_o the_o air_n be_v include_v with_o its_o ordinary_a tensure_n it_o sustain_v the_o quicksilver_n at_o the_o height_n of_o 29_o inch_n as_o if_o less_o than_o that_o weight_n be_v too_o little_a to_o stretch_v the_o quicksilver_n into_o that_o suppose_a fine_a substance_n but_o when_o that_o air_n by_o pump_v be_v weaken_v it_o will_v sink_v to_o 20_o 10_o 5_o yea_o less_o than_o 1_o inch_n of_o height_n as_o if_o now_o less_o than_o the_o weight_n of_o 1_o inch_n be_v enough_o so_o to_o stretch_v it_o as_o less_o than_o 29_o inch_n will_v not_o do_v before_o yet_o be_v no_o alteration_n all_o this_o while_n make_v in_o the_o texture_n of_o the_o quicksilver_n but_o in_o the_o tensure_n of_o the_o air_n only_o it_o be_v therefore_o from_o this_o different_a tensure_n or_o spring_n of_o the_o air_n not_o from_o any_o difference_n in_o the_o quicksilver_n that_o it_o stand_v sometime_o at_o a_o high_a sometime_o at_o a_o low_a station_n and_o what_o have_v be_v thus_o say_v of_o this_o torricellian_a experiment_n be_v easy_o applicable_a to_o other_o of_o like_a nature_n and_o it_o be_v confess_v that_o as_o the_o notion_n of_o fuga_fw-la vacui_fw-la or_o that_o of_o the_o air_n pressure_n do_v stand_v or_o fall_v as_o to_o this_o experiment_n so_o must_v it_o do_v as_o to_o the_o other_o also_o i_o content_v myself_o therefore_o to_o have_v show_v it_o in_o this_o without_o expatiate_v to_o other_o particular_n finis_fw-la