subtraction_n of_o air_n and_o many_o the_o like_a experiment_n make_v by_o mr._n boyle_n a_o honourable_a member_n of_o this_o society_n in_o that_o pneumatick_a engine_n of_o his_o invention_n but_o while_o i_o name_v these_o i_o do_v anticipate_v what_o i_o be_o next_o to_o handle_v which_o be_v the_o compression_n of_o springy_a body_n we_o have_v be_v hitherto_o discourse_v of_o such_o fluid_n principal_o as_o water_n be_v suppose_v to_o be_v that_o be_v fluids_n uncapable_a of_o compression_n because_o not_o elastical_a or_o springy_a but_o springy_a fluid_n such_o as_o we_o suppose_v the_o air_n to_o be_v may_v by_o a_o incumbent_a weight_n not_o only_o suffer_v a_o trusion_n as_o water_n may_v into_o another_o place_n as_o from_o a_o to_o b_o and_o e_z in_o a_o open_a pipe_n in_o fig._n 17_o but_o a_o compression_n into_o a_o less_o place_n as_o for_o instance_n if_o the_o pipe_n be_v close_o stop_v at_o c_o or_o hermetical_o seal_v so_o as_o ab_fw-la be_v water_n and_o bc_n air_n or_o other_o springy_a fluid_n a_o superfusion_n or_o addition_n of_o the_o weight_n ad_fw-la whether_o fluid_a or_o solid_a will_v raise_v b_o to_o e_z and_o contract_v the_o air_n bc_n into_o the_o space_n aec_fw-la that_o be_v so_o much_o as_o till_o the_o spring_n in_o cb_n which_o be_v a_o strength_n equivalent_a to_o the_o pressure_n of_o ab_fw-la become_v by_o this_o contraction_n equivalent_a to_o the_o pressure_n of_o db._n and_o if_o more_o yet_o be_v superfuse_v on_o d_o ce_fw-fr will_v be_v yet_o more_o contract_v and_o so_o onward_o the_o strength_n of_o the_o spring_n be_v still_o make_v equivalent_a to_o the_o pressure_n of_o the_o weight_n for_o while_o the_o spring_n cb_n be_v too_o weak_a the_o weight_n be_v a_o great_a strength_n will_v thrust_v it_o close_o and_o if_o ce_fw-fr be_fw-mi too_o strong_a it_o will_v as_o a_o great_a strength_n thrust_v away_o that_o pressure_n and_o can_v never_o rest_v but_o when_o the_o strength_n of_o the_o spring_n be_v just_a equivalent_a to_o the_o pressure_n so_o in_o solid_n if_o for_o instance_n a_o room_n or_o vessel_n be_v fill_v with_o wool_n as_o high_a as_o bb_v fig._n 25._o and_o more_o wool_n or_o other_o weight_n whither_o heavy_a or_o light_a than_o wool_n be_v lay_v on_o as_o to_o aa_n the_o wool_n shall_v be_v depress_v to_o le_z and_o more_o yet_o if_o more_o weight_n be_v lay_v on_o and_o in_o like_a manner_n if_o bcb_n be_v air_n and_o this_o press_v either_o by_o the_o incumbent_a air_n ab_fw-la suppose_v air_n to_o be_v heavy_a or_o by_o a_o solid_a weight_n or_o force_n so_o close_o on_o all_o side_n as_o that_o the_o air_n can_v pass_v by_o or_o through_o it_o and_o this_o be_v grant_v the_o torricellian_a experiment_n with_o other_o of_o the_o same_o nature_n be_v confess_o solve_v by_o the_o pressure_n of_o the_o air_n which_o be_v ancient_o think_v to_o be_v by_o a_o fuga_fw-la vacui_fw-la for_o if_o the_o air_n be_v heavy_a it_o must_v gravitate_fw-la that_o be_v endeavour_v a_o descent_n as_o other_o heavy_a body_n do_v and_o actual_o effect_v it_o if_o not_o oppose_v by_o at_o least_o as_o great_a a_o strength_n and_o the_o spring_n of_o the_o air_n allow_v it_o to_o have_v a_o spring_n must_v always_o be_v of_o such_o a_o texture_n as_o be_v equivalent_a to_o the_o weight_n or_o force_n which_o it_o bear_v now_o as_o to_o the_o weight_n of_o air_n or_o its_o positive_a gravity_n the_o peripatetic_a philosophy_n do_v not_o acknowledge_v it_o but_o take_v it_o to_o be_v positive_o light_a and_o consequent_o to_o endeavour_v a_o ascent_n and_o some_o other_o say_v the_o same_o not_o only_o as_o to_o air_n but_o as_o to_o all_o heavy_a body_n and_o whereas_o we_o suppose_v in_o they_o a_o positive_a gravity_n and_o that_o what_o we_o call_v levity_n be_v but_o comparative_o so_o be_v only_a gravity_n in_o a_o less_o degree_n they_o take_v levity_n to_o be_v positive_a and_o gravity_n to_o be_v but_o a_o less_o degree_n of_o levity_n and_o consequent_o those_o heavy_a body_n not_o to_o affect_v a_o descent_n but_o to_o be_v thrust_v down_o by_o body_n more_o light_a which_o more_o strong_o affect_v a_o high_a place_n but_o against_o these_o the_o one_o and_o the_o other_o i_o apprehend_v as_o to_o philosophy_n these_o inconvenience_n which_o to_o i_o seem_v cogent_a argument_n if_o this_o motion_n up-ward_n be_v natural_a it_o must_v be_v either_o a_o averseness_n from_o the_o centre_n as_o the_o terminus_n à _fw-fr quo_fw-la or_o a_o propension_n to_o some_o other_o place_n as_o the_o terminus_n ad_fw-la quem_fw-la if_o they_o say_v the_o former_a it_o be_v true_a that_o then_o b_o oughts_z to_z move_z from_o c_o in_o perpendicular_a line_n as_o cba_n fig._n 26_o and_o the_o phaenomenon_n do_v not_o contradict_v it_o but_o if_o the_o first_o intendmnent_n of_o nature_n be_v not_o to_o be_v here_o without_o any_o positive_a tendency_n where_o to_o be_v it_o seem_v much_o more_o intelligible_a that_o somewhat_o shall_v thrust_v it_o thence_o by_o somewhat_o more_o forcible_o press_v between_o than_o that_o it_o shall_v fly_v thence_o without_o affectation_n of_o any_o other_o place_n but_o if_o they_o say_v as_o seem_v more_o rational_a if_o levity_n be_v the_o positive_a principle_n that_o it_o be_v a_o affectation_n of_o some_o high_a place_n suppose_v a_o while_o b_o be_v just_a between_o c_o and_o a_o the_o motion_n it_o be_v true_a will_v be_v in_o the_o perpendicular_a cba_n as_o the_o straight_a way_n thither_o but_o if_o it_o be_v any_o where_o else_o as_o at_o d_o then_o its_o motion_n to_o a_o will_v not_o be_v in_o dce_n the_o perpendicular_a but_o in_o da_fw-la a_o oblique_a line_n which_o be_v contrary_a to_o all_o experience_n for_o the_o same_o light_a body_n wherever_o it_o be_v move_v upward_o in_o a_o perpendicular_a as_o well_o as_o a_o heavy_a body_n in_o a_o perpendicular_a downward_o and_o if_o to_o avoid_v this_o they_o will_v say_v that_o it_o move_v not_o to_o a_o certain_a place_n as_o a_o or_o e_o determinate_o but_o to_o that_o place_n whatever_o it_o be_v that_o be_v just_a over_o it_o i_o say_v this_o be_v not_o proper_o the_o move_n to_o a_o place_n if_o it_o be_v indifferent_a whether_o to_o a_o or_o to_o e_o but_o rather_o a_o move_n from_o a_o place_n that_o be_v to_o be_v as_o far_o from_o c_o as_o it_o can_v which_o be_v the_o former_a branch_n of_o the_o supposition_n and_o against_o which_o we_o do_v before_o urge_v the_o former_a inconvenience_n which_o make_v it_o not_o likely_a that_o there_o be_v any_o such_o thing_n as_o positive_a lightness_n at_o all_o since_o it_o will_v be_v hard_a to_o assign_v what_o shall_v be_v the_o terminus_n ad_fw-la quem_fw-la which_o such_o a_o mover_n aim_v at_o but_o wave_v this_o argument_n from_o philosophy_n at_o large_a i_o shall_v argue_v from_o experiment_n as_o to_o the_o air_n thus_o suppose_v we_o air_n in_o the_o bladder_n aa_n fig._n 27._o of_o the_o same_o tensure_n with_o the_o external_n air_n and_o therefore_o such_o as_o will_v not_o as_o they_o speak_v gravitate_fw-la or_o as_o i_o will_v rather_o say_v praegravitate_fw-la thereon_o nor_o yet_o praelevitate_fw-la be_v of_o the_o same_o specifical_a gravity_n or_o levity_n with_o it_o if_o this_o be_v compress_v into_o a_o less_o room_n as_o bb_v it_o will_v then_o retain_v the_o same_o quantity_n of_o gravity_n or_o levity_n as_o before_o since_o all_o that_o air_n be_v still_o here_o with_o all_o its_o positive_a quality_n but_o because_o now_o within_o less_o dimension_n it_o will_v be_v gradual_o or_o as_o now_o the_o language_n be_v specifical_o more_o than_o before_o heavy_a or_o light_a according_a as_o that_o positive_a quality_n be_v gravity_n or_o levity_n for_o as_o the_o same_o quantity_n of_o heat_n in_o lesser_a space_n make_v the_o subject_n intensive_o hot_a so_o the_o same_o quantity_n of_o heaviness_n in_o a_o less_o room_n make_v it_o intensive_o heavy_a and_o of_o lightness_n light_a but_o experience_n testify_v as_o be_v confess_v that_o compress_a air_n be_v intensive_o heavy_a or_o as_o we_o now_o speak_v specifical_o heavy_a and_o on_o the_o balance_n be_v find_v so_o to_o be_v not_o light_a than_o before_o therefore_o its_o positive_a quality_n be_v heaviness_n not_o lightness_n the_o positive_a gravity_n of_o the_o air_n be_v thus_o evince_v and_o consequent_o that_o the_o air_n ascend_v only_o because_o it_o be_v thrust_v up_o by_o body_n more_o heavy_a like_a as_o water_n rise_v upon_o the_o cast_n in_o of_o earth_n or_o other_o heavy_a body_n the_o torricellian_a experiment_n with_o other_o the_o like_a phaenomena_n be_v easy_o solve_v from_o statical_a principle_n without_o have_v recourse_n to_o a_o fuga_fw-la vacui_fw-la for_o admit_v as_o before_o that_o in_o a_o vessel_n with_o a_o nose_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
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
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
themselves_o and_o himself_o grant_v essay_n p._n 14._o that_o air_n in_o a_o bladder_n do_v gravitate_fw-la on_o water_n to_o avoid_v the_o pressure_n of_o these_o evidence_n it_o be_v now_o allege_a that_o the_o oil_n or_o water_n in_o the_o pipe_n a_o in_o fig._n 5._o though_o not_o intrinsical_o heavy_a yet_o it_o be_v high_a position_n give_v it_o a_o accidental_a weight_n more_o than_o that_o in_o the_o vessel_n and_o hence_o it_o come_v to_o pass_v that_o that_o do_v depress_v this._n but_o he_o do_v not_o consider_v that_o this_o do_v destroy_v the_o whole_a design_n of_o his_o second_o chapter_n which_o be_v to_o prove_v that_o c_o do_v not_o gravitate_fw-la on_o d_o nor_o d_o on_o e_z in_o fig._n 14_o that_o be_v that_o the_o upper_a part_n of_o the_o water_n do_v not_o gravitate_fw-la on_o the_o nether_a whereas_o if_o mere_o a_o high_a position_n will_v make_v it_o gravitate_fw-la and_o that_o not_o only_a ad_fw-la pondus_fw-la but_o ad_fw-la motum_fw-la also_o then_o must_v the_o water_n be_v in_o perpetual_a motion_n the_o upper_a part_n still_o press_v away_o the_o nether_a like_v as_o on_o another_o account_n it_o happen_v in_o boil_a water_n i_o mean_v when_o the_o fire_n be_v under_o it_o for_o if_o it_o be_v heat_v by_o fire_n above_o it_o the_o case_n be_v much_o alter_v which_o perpetual_a motion_n the_o say_a author_n there_o urge_v as_o a_o great_a absurdity_n yet_o i_o be_o not_o ignorant_a that_o mr._n boyle_n be_v indeed_o of_o opinion_n that_o in_o all_o fluid_v the_o minute_n part_n be_v in_o continual_a motion_n make_v this_o the_o specific_a nature_n of_o fluidity_n as_o contradistinct_a of_o fixedness_n but_o that_o be_v on_o another_o account_n and_o concern_v not_o this_o point_n at_o all_o it_o be_v not_o therefore_o safe_a for_o our_o antagonist_n to_o ascribe_v it_o only_o to_o the_o accidental_a weight_n of_o a_o high_a position_n nor_o be_v it_o sound_v so_o to_o do_v it_o be_v true_a that_o a_o different_a position_n may_v give_v to_o the_o same_o weight_n a_o different_a ponderation_n as_o for_o instance_n a_o weight_n at_o g_o in_o fig._n 15._o will_v ponderate_v more_o than_o at_o h_n not_o because_o high_a but_o because_o at_o g_o it_o be_v to_o descend_v direct_o but_o at_o h_n on_o a_o oblique_a plain_n which_o abate_v its_o force_n and_o do_v more_o abate_v it_o as_o it_o be_v more_o oblique_a and_o a_o weight_n at_o rest_n in_o f_o or_o e_o be_v of_o less_o force_n to_o move_v the_o balance_n than_o when_o from_o a_o it_o fall_v to_o e_o and_o less_o there_o than_o when_o it_o be_v fall_v to_o f_o and_o even_o this_o less_o than_o if_o it_o have_v be_v violent_o throw_v down_o because_o in_o the_o latter_a cse_n there_o be_v a_o great_a contract_a impetus_fw-la again_o at_o e_o or_o f_o it_o will_v ponderate_v more_o than_o at_o ay_o or_o k_o because_o those_o suspend_v at_o a_o be_v at_o a_o great_a distance_n from_o the_o centre_n c_o than_o those_o suspend_v at_o d_o the_o different_a position_n in_o all_o these_o and_o many_o other_o the_o like_a case_n give_v to_o the_o same_o weight_n a_o accidental_a additional_a force_n but_o a_o high_a position_n mere_o because_o high_a give_v no_o such_o advantage_n at_o all_o the_o weight_n at_o e_z be_v but_o just_a of_o the_o same_o force_n as_o at_o f_o and_o at_o ay_o as_o at_o k._n for_o the_o length_n or_o shortness_n of_o the_o string_n on_o which_o it_o hang_v do_v not_o at_o all_o alter_v the_o weight_n as_o be_v agree_v by_o all_o and_o experience_n testify_v the_o reason_n therefore_o of_o this_o phaenomenon_n be_v not_o because_o that_o at_o a_o in_o a_o high_a position_n be_v of_o a_o great_a weight_n than_o a_o like_a quantity_n at_o b_o but_o because_o the_o part_n at_o c_o in_o fig._n 5._o be_v more_o press_v than_o those_o at_o b_o as_o bear_v the_o weight_n of_o ca_n which_o b_o bear_v not_o whereby_o c_o be_v press_v down_o and_o b_o thereby_o press_v up_o but_o against_o this_o explication_n he_o bring_v a_o experiment_n on_o w_z ch_z he_o lay_v great_a weight_n a_o porringer_n fill_v with_o lead_n etc._n etc._n which_o in_o the_o air_n as_o at_o a_o weigh_v 78_o ounce_n weigh_v in_o the_o water_n about_o 68½_n ounce_n and_o the_o same_o weight_n it_o hold_v with_o some_o inconsiderable_a difference_n which_o he_o excuse_v whether_o at_o c_o the_o depth_n of_o 40_o or_o 25_o inch_n or_o at_o d_o the_o depth_n of_o but_o 12_o or_o scarce_o 1_o inch_n fig._n 16._o where_o he_o attempt_v the_o account_n of_o two_o phaenomena_n first_o why_o it_o weigh_v less_o in_o water_n than_o in_o air_n and_o second_o why_o it_o weigh_v alike_o at_o several_a depth_n in_o water_n why_o it_o shall_v weigh_v less_o in_o water_n than_o in_o air_n he_o ascribe_v to_o the_o resistance_n and_o crassitude_n of_o the_o water_n and_o he_o tell_v we_o elsewhere_o that_o if_o we_o strike_v with_o our_o hand_n the_o surface_n of_o water_n we_o shall_v find_v its_o resistance_n not_o much_o less_o than_o if_o we_o strike_v a_o board_n by_o which_o if_o he_o mean_v the_o viscosity_n or_o resistance_n to_o separation_n he_o speak_v not_o to_o the_o present_a purpose_n for_o as_o to_o that_o it_o be_v to_o be_v so_o far_o consider_v as_o a_o firm_a body_n not_o a_o fluid_a which_o be_v that_o we_o be_v now_o speak_v of_o but_o if_o he_o mean_v a_o resistance_n to_o be_v displace_v and_o thrust_v upward_o to_o make_v way_n for_o the_o porringer_n descent_n he_o say_v just_a the_o same_o thing_n with_o we_o for_o such_o resistance_n be_v proper_o gravitation_n and_o do_v countergravitate_fw-la to_o that_o of_o the_o porringer_n and_o take_v off_o so_o much_o of_o its_o praegravitation_n just_o as_o when_o the_o scale_n b_o fig._n 16._o by_o its_o gravitation_n resist_v the_o descent_n of_o a_o because_o a_o can_v descend_v without_o the_o ascent_n of_o b_o to_o which_o by_o reason_n of_o its_o gravitation_n it_o be_v averse_a and_o because_o the_o porringer_n can_v descend_v but_o by_o thrust_v up_o so_o much_o water_n the_o water_n must_v needs_o give_v so_o much_o resistance_n to_o this_o descent_n as_o it_o give_v to_o its_o own_o ascent_n that_o be_v so_o much_o as_o the_o weight_n of_o the_o water_n that_o must_v ascend_v and_o have_v just_a the_o same_o effect_n as_o if_o so_o much_o water_n be_v put_v into_o the_o scale_n b._n and_o just_o so_o much_o the_o porringer_n weigh_v less_o in_o the_o water_n than_o in_o the_o air._n and_o as_o to_o what_o he_o say_v of_o the_o great_a resistance_n which_o the_o hand_n find_v when_o we_o strike_v hard_o on_o the_o water_n we_o be_v to_o consider_v not_o only_o the_o weight_n of_o the_o water_n but_o the_o swiftness_n requisite_a to_o make_v way_n for_o the_o hand_n move_v so_o fast_o like_a as_o if_o a_o weight_n of_o 10_o pound_n hang_v in_o the_o air_n by_o a_o thread_n the_o least_o touch_n of_o the_o finger_n will_v move_v it_o slow_o but_o to_o move_v it_o 10_o time_n so_o fast_o will_v require_v a_o force_n 10_o time_n as_o strong_a and_o if_o you_o strike_v it_o hard_o with_o a_o swift_a stroke_n of_o the_o hand_n that_o which_o make_v very_o little_a resistance_n to_o a_o gentle_a touch_n will_v considerable_o withstand_v the_o stroke_n of_o a_o swift_a hand_n not_o because_o the_o weight_n be_v 10_o time_n heavy_a than_o before_o or_o do_v 10_o time_n as_o much_o resist_v motion_n but_o because_o it_o do_v 10_o time_n as_o much_o resist_v a_o motion_n 10_o time_n as_o swift_a now_o so_o much_o strength_n as_o be_v requisite_a to_o move_v so_o much_o water_n with_o so_o much_o swiftness_n as_o be_v necessary_a to_o make_v way_n for_o so_o swift_a a_o motion_n of_o the_o hand_n so_o much_o resistance_n must_v the_o water_n give_v to_o such_o a_o stroke_n from_o its_o own_o gravity_n without_o the_o assistance_n of_o the_o suppose_a crassitude_n or_o viscosity_n but_o when_o in_o the_o present_a case_n we_o consider_v how_o much_o the_o porringer_n weigh_v in_o water_n we_o consider_v only_o whether_o it_o remove_v so_o much_o weight_n though_o never_o so_o slow_o not_o with_o what_o swiftness_n it_o will_v remove_v it_o and_o as_o to_o that_o a_o very_a little_a weight_n more_o than_o what_o it_o move_v will_v suffice_v but_o his_o main_a objection_n lie_v in_o the_o other_o point_n that_o the_o porringer_n weigh_v as_o heavy_a at_o d_o the_o depth_n of_o 12_o or_o but_o of_o 1_o inch_n as_o at_o c_o the_o depth_n of_o 25_o or_o 40_o inch_n fig._n 16._o and_o just_o so_o say_v i_o it_o ought_v to_o be_v for_o every_o thing_n weigh_v in_o water_n just_a so_o much_o as_o its_o weight_n be_v heavy_a than_o so_o much_o water_n as_o for_o instance_n
if_o the_o plain_a δδ_n fig._n 16._o be_v in_o all_o part_n equal_o press_v it_o be_v confess_o the_o same_o as_o if_o not_o press_v at_o all_o for_o so_o long_o there_o be_v no_o reason_n why_o one_o part_n shall_v rise_v rather_o than_o another_o and_o so_o it_o will_v be_v if_o d_o be_v just_a as_o heavy_a as_o so_o much_o water_n but_o if_o d_o be_v heavy_a than_o be_v that_o part_n of_o it_o overcharge_v just_o so_o much_o as_o d_o be_v heavy_a than_o so_o much_o water_n as_o will_v fill_v the_o place_n if_o this_o be_v absent_a and_o therefore_o if_o not_o relieve_v by_o so_o much_o weight_n in_o the_o scale_n b_o it_o will_v sink_v and_o just_o so_o much_o will_v serve_v at_o c_o that_o be_v it_o must_v weigh_v equal_o whether_o at_o the_o depth_n of_o c_o or_o d_o or_o any_o other_o depth_n but_o say_v he_o if_o the_o incumbent_a water_n do_v gravitate_fw-la on_o d_o it_o will_v more_o gravitate_fw-la on_z c_o because_o at_o a_o great_a depth_n true_o it_o do_v so_o but_o as_o the_o pressure_n at_o c_o be_v great_a than_o at_o d_o so_o be_v the_o counterpressure_n at_o χ_n more_o than_o at_o δ_n and_o just_o so_o much_o more_o so_o that_o whatever_o be_v the_o pregravitation_n at_o d_o must_v be_v the_o pregravitation_n at_o c_o also_o and_o it_o be_v the_o pregravitation_n only_o that_o be_v weigh_v just_o as_o when_o the_o scale_n a_o outweigh_v b_o by_o 5_o ounce_n and_o into_o each_o scale_n you_o put_v 10_o pound_n it_o will_v yet_o outweigh_v but_o just_a 5_o ounce_n as_o it_o do_v before_o so_o that_o his_o argument_n from_o this_o experiment_n will_v not_o hold_v against_o we_o and_o the_o solution_n he_o give_v will_v hold_v as_o little_a it_o be_v say_v he_o because_o the_o porringer_n drive_v up_o no_o more_o water_n out_o of_o its_o place_n at_o the_o one_o station_n than_o at_o the_o other_o but_o this_o be_v a_o mistake_n for_o while_o the_o pillar_n α_n c_o fig._n 16._o to_o make_v room_n for_o the_o porringer_n drive_v away_o the_o water_n from_o c_o to_o χ_n that_o at_o χ_n thrust_v up_o all_o above_o it_o as_o high_a as_o α_n to_o make_v room_n for_o itself_o as_o α_n d_o do_v all_o that_o over_o δ_n so_o that_o the_o water_n displace_v be_v not_o the_o same_o in_o both_o and_o therefore_o the_o porrigner_n if_o not_o assist_v by_o the_o incumbent_a water_n will_v not_o equal_o weigh_v in_o different_a depth_n contrary_a to_o his_o own_o experiment_n which_o therefore_o make_v against_o himself_o but_o the_o great_a plausible_a objection_n be_v that_o a_o man_n under_o water_n feel_v not_o the_o weight_n of_o it_o and_o why_o say_v he_o but_o because_o man_n body_n be_v heavy_a than_o so_o much_o water_n the_o water_n do_v not_o gravitate_fw-la on_o it_o but_o this_o reason_n be_v as_o the_o school_n speak_v non_fw-la causa_fw-la pro_fw-la causa_fw-la if_o the_o question_n be_v why_o the_o water_n do_v not_o raise_v the_o body_n as_o it_o will_v do_v so_o much_o wood_n the_o reason_n have_v be_v good_a because_o so_o much_o water_n do_v not_o press_v downward_o more_o than_o the_o body_n do_v and_o therefore_o be_v not_o able_a to_o press_v it_o away_o but_o when_o the_o question_n be_v why_o a_o man_n do_v not_o feel_v it_o that_o be_v why_o he_o be_v not_o hurt_v by_o it_o or_o put_v to_o pain_n the_o answer_n because_o specifical_o light_a will_v not_o serve_v for_o 1._o a_o man_n by_o this_o reason_n shall_v not_o feel_v the_o weight_n of_o wood_n because_o proportionable_o light_a than_o himself_o yet_o we_o find_v a_o man_n will_v as_o much_o sink_n under_o a_o load_n of_o wood_n as_o a_o load_n of_o lead_n if_o of_o equal_a weight_n and_o if_o it_o be_v say_v this_o be_v because_o though_o the_o man_n be_v not_o yet_o the_o air_n about_o he_o be_v light_a than_o that_o wood_n i_o say_v it_o be_v so_o but_o this_o shall_v therefore_o cause_v only_o a_o lateral_a pressure_n on_o that_o air_n not_o a_o direct_a pressure_n on_o the_o man._n and_o though_o a_o man_n stand_v up_o to_o the_o neck_n in_o water_n he_o shall_v yet_o find_v the_o burden_n of_o the_o wood_n lay_v on_o his_o shoulder_n notwithstanding_o that_o both_o the_o man_n and_o all_o about_o he_o be_v proportionable_o heavy_a than_o wood._n and_o he_o shall_v equal_o feel_v it_o as_o if_o it_o be_v a_o equal_a weight_n of_o lead_n if_o both_o be_v above_o the_o water_n so_o that_o the_o circumjacent_a air_n be_v not_o that_o which_o make_v the_o wood_n weigh_v upon_o the_o man._n 2._o though_o the_o whole_a man_n be_v heavy_a than_o so_o much_o water_n yet_o many_o part_n of_o he_o be_v light_a and_o will_v of_o themselves_o swim_v in_o water_n though_o by_o their_o connexion_n with_o some_o heavy_a they_o be_v make_v to_o sink_v like_o wood_n tie_v to_o a_o piece_n of_o lead_n now_o all_o these_o part_n at_o least_o aught_o to_o feel_v pain_n if_o the_o specific_a gravity_n be_v the_o only_a cause_n of_o indolency_n but_o do_v not_o 3._o a_o man_n immerse_v in_o quicksilver_n which_o be_v a_o heavy_a fluid_n though_o he_o will_v thereby_o be_v boy_v up_o yet_o will_v he_o no_o more_o feel_v the_o incumbent_a weight_n than_o a_o like_a weight_n of_o water_n and_o though_o the_o experiment_n can_v so_o convenient_o be_v make_v in_o quicksilver_n as_o in_o water_n yet_o as_o to_o part_v it_o may_v be_v make_v by_o thrust_v the_o hand_n into_o quicksilver_n which_o shall_v no_o more_o be_v press_v by_o it_o than_o if_o thrust_v into_o a_o equivalent_a depth_n of_o water_n that_o be_v about_o 14_o time_n as_o deep_a and_o fly_n or_o other_o small_a animal_n immerse_v in_o quicksilver_n be_v not_o thereby_o press_v to_o death_n but_o do_v safe_o emerge_n to_o the_o top._n so_o that_o it_o be_v but_o a_o fancy_n to_o think_v that_o only_o the_o proportional_a or_o specific_a lightness_n of_o the_o water_n be_v the_o cause_n of_o that_o indolence_n since_o liquids_n proportionable_o heavy_a if_o not_o positive_o heavy_a will_v be_v feel_v as_o little_a 4._o let_v we_o suppose_v a_o invert_v syphon_n fig._n 17._o fill_v from_o a_o to_o b_o with_o quicksilver_n from_o thence_o to_o c_z with_o water_n so_o high_a as_o to_o balance_v the_o quicksilver_n at_o a._n if_o now_o oil_n which_o be_v light_a than_o either_o be_v pour_v on_o a_o i_o ask_v whether_o the_o quicksilver_n at_o a_o will_v not_o be_v thereby_o depress_v and_o that_o at_o b_o and_o c_o raise_v certain_o it_o will_n but_o why_o the_o oil_n can_v by_o their_o principle_n gravitate_fw-la on_o ab_fw-la because_o this_o be_v quicksilver_n nor_o yet_o as_o they_o speak_v mediate_o upon_o bc_n for_o even_o this_o be_v water_n and_o therefore_o heavy_a than_o oil_n no_o nor_o on_o the_o air_n above_o c_o for_o the_o oil_n at_o da_fw-la be_v already_o low_a than_o it_o and_o therefore_o can_v affect_v to_o possess_v its_o place_n it_o shall_v therefore_o by_o their_o principle_n not_o gravitate_fw-la at_o all_o since_o there_o be_v nothing_o below_o it_o light_a than_o itself_o on_o which_o it_o shall_v gravitate_fw-la yet_o gravitate_fw-la we_o see_v it_o will_v and_o thrust_v out_o of_o place_n that_o whole_a body_n abc_n notwithstanding_o if_o that_o be_v considerable_a the_o high_a position_n of_o c_o and_o its_o great_a specific_a heaviness_n and_o all_o this_o while_n the_o animal_n in_o bc_n shall_v remain_v unhurt_a notwithstanding_o there_o be_v not_o only_a gravitatio_fw-la ad_fw-la pondus_fw-la but_o gravitatio_fw-la ad_fw-la motum_fw-la too_o so_o that_o the_o notion_n of_o non-gravitation_a on_o a_o fluid_n not_o specifical_o light_a than_o itself_o be_v quite_o out_o of_o door_n and_o the_o truth_n be_v suppose_v abc_n to_o be_v in_o equipoise_n the_o superfusion_n of_o ad_fw-la will_n equal_o depress_v a_o whatever_o the_o liquor_n be_v if_o the_o weight_n be_v equal_a and_o ounce_n weight_n will_v still_o be_v a_o ounce_n weight_n and_o a_o ounce_n weight_n will_v just_o so_o much_o depress_v the_o quicksilver_n whether_o it_o be_v a_o ounce_n of_o wine_n water_n oil_n or_o quicksilver_n that_o be_v just_o so_o much_o as_o to_o thrust_v half_o that_o weight_n out_o of_o the_o leg_n of_o fig._n 17._o into_o the_o leg_n fc_n without_o any_o regard_n have_v to_o the_o specific_a gravity_n or_o levity_n of_o the_o liquor_n ad_fw-la which_o as_o to_o this_o point_n be_v of_o no_o consideration_n at_o all_o and_o if_o the_o high_a position_n of_o d_o above_o a_o be_v think_v of_o moment_n the_o high_a position_n of_o c_o above_o both_o must_v be_v so_o too_o and_o there_o will_v be_v nothing_o steady_a to_o fix_v upon_o but_o that_o the_o positive_a weight_n of_o df_n be_v at_o least_o in_o proportion_n to_o the_o bigness_n of_o the_o pipe_n
abate_v but_o here_o he_o proceed_v upon_o a_o mistake_n also_o for_o though_o it_o be_v very_o true_a that_o water_n will_v flow_v upon_o a_o declivity_n yet_o not_o as_o fluid_v but_o as_o heavy_a for_o we_o see_v a_o bowl_n run_v down_o a_o hill_n though_o not_o a_o fluid_a but_o a_o solid_a body_n and_o a_o broad_a solid_a lie_v on_o a_o narrow_a pillar_n in_o fig._n 22._o have_v in_o every_o part_n a_o lateral_a pressure_n as_o well_o as_o water_n and_o if_o it_o be_v cut_v in_o the_o midst_n will_v fall_v off_o on_o either_o side_n as_o water_n will_v do_v and_o when_o it_o do_v not_o the_o reason_n be_v not_o a_o want_n of_o propension_n but_o because_o this_o lateral_a propension_n be_v check_v or_o impede_v by_o a_o great_a strength_n of_o cohesion_n like_v as_o its_o perpendicular_a propension_n be_v check_v by_o that_o great_a strength_n of_o the_o pillar_n and_o like_v as_o the_o pillar_n if_o too_o weak_a will_v break_v under_o the_o perpendicular_a weight_n so_o if_o the_o strength_n of_o cohesion_n be_v less_o than_o its_o lateral_a propension_n the_o solid_a will_v divide_v as_o a_o fluid_a will_v do_v as_o when_o a_o solid_a break_v by_o its_o own_o weight_n in_o fig._n 23._o on_o the_o contrary_a water_n in_o a_o pail_n or_o other_o vessel_n though_o a_o fluid_a have_v its_o lateral_a propension_n restrain_v by_o the_o side_n of_o the_o vessel_n as_o by_o a_o great_a strength_n but_o do_v not_o lose_v it_o and_o if_o the_o side_n chance_v not_o to_o be_v strong_a enough_o will_v break_v through_o do_v at_o least_o endeavour_v it_o though_o they_o be_v strong_a enough_o so_o that_o both_o in_o solid_n and_o fluid_n each_o particle_n have_v its_o lateral_a propension_n as_o well_o as_o perpendicular_a though_o it_o be_v sometime_o restrain_v or_o overpower_v there_o by_o the_o cohesion_n of_o part_n here_o by_o the_o strength_n of_o the_o side_n but_o in_o both_o case_n if_o those_o strength_n be_v too_o weak_a that_o propension_n prevail_v now_o as_o this_o lateral_a propension_n of_o fluids_n be_v keep_v in_o by_o the_o side_n of_o the_o vessel_n as_o to_o the_o utmost_a part_n of_o it_o so_o as_o to_o the_o inner_a part_n of_o it_o they_o keep_v in_o each_o other_o the_o lateral_a pressure_n of_o a_o fig._n 24._o be_v sustain_v by_o that_o of_o b_o and_o this_o by_o that_o not_o as_o by_o great_a but_o as_o by_o equal_a strength_n for_o a_o can_v thrust_v away_o b_o without_o thrust_v up_o a_o body_n as_o heavy_a as_o itself_o nor_o b_o thrust_v away_o a._n so_o that_o the_o lateral_a pressure_n of_o the_o part_n be_v mutual_o sustain_v each_o by_o other_o and_o the_o perpendicular_a pressure_n by_o the_o part_n under_o it_o hence_o it_o come_v to_o pass_v that_o those_o under-part_n bear_v only_o the_o pressure_n of_o a_o column_n and_o no_o more_o which_o be_v the_o expedient_a that_o i_o intimate_v but_o now_o and_o therefore_o in_o the_o heap_n of_o wheat_n but_o now_o mention_v though_o upon_o a_o aperture_n in_o the_o bottom_n more_o fall_v down_o than_o such_o a_o pillar_n because_o when_o that_o be_v go_v the_o lateral_a pressure_n of_o the_o rest_n do_v operate_v yet_o while_o that_o pillar_n be_v there_o that_o part_n of_o the_o bottom_n do_v bear_v no_o more_o but_o it_o but_o if_o these_o expedient_n of_o his_o do_v not_o serve_v what_o be_v the_o reason_n you_o will_v ask_v that_o the_o man_n under_o water_n feel_v not_o the_o weight_n of_o it_o i_o will_v answer_v first_o that_o it_o be_v not_o agree_v that_o at_o a_o great_a depth_n a_o man_n shall_v feel_v no_o pain_n at_o all_o and_o i_o hear_v that_o mr._n gratrix_fw-la have_v contrive_v a_o way_n of_o take_v breath_n at_o a_o great_a depth_n under_o water_n through_o long_a pipe_n reach_v to_o the_o top_n of_o it_o yet_o find_v his_o breast_n there_o so_o compress_a by_o the_o water_n that_o he_o can_v not_o draw_v breath_n but_o in_o small_a depth_n of_o water_n i_o do_v not_o deny_v but_o that_o a_o man_n may_v remain_v for_o some_o time_n without_o any_o considerable_a pain_n the_o reason_n i_o judge_v be_v this_o because_o the_o man_n encompass_v by_o a_o fluid_a whether_o specifical_o heavy_a or_o light_a than_o himself_o it_o make_v no_o matter_n be_v equal_o press_v on_o all_o side_n and_o thereby_o suffer_v no_o luxation_n of_o part_n and_o consequent_o no_o sense_n of_o pain_n but_o upon_o the_o luxation_n or_o laceration_n of_o any_o part_n especial_o a_o nervous_a part_n pain_n arise_v hence_o it_o be_v that_o our_o flesh_n feel_v not_o the_o hardness_n of_o our_o bone_n because_o so_o fit_v thereunto_o as_o to_o suffer_v no_o luxation_n or_o laceration_n by_o it_o but_o if_o the_o bone_n be_v break_v or_o dislocate_v we_o shall_v then_o find_v it_o to_o hurt_v we_o and_o feel_v it_o hard_a and_o sharp_a and_o though_o the_o body_n by_o such_o compression_n may_v be_v contract_v into_o a_o less_o room_n by_o reason_n of_o the_o air_n blood_n and_o other_o springy_a liquid_n yet_o these_o be_v all_o uniform_o press_v without_o any_o tear_n of_o the_o nervous_a part_n he_o suffer_v nothing_o of_o pain_n from_o it_o and_o hence_o it_o be_v that_o the_o eggshell_n but_o now_o mention_v though_o press_v by_o a_o body_n specifical_o heavy_a than_o itself_o by_o which_o therefore_o according_a to_o their_o principle_n it_o ought_v to_o be_v crush_v receive_v no_o prejudice_n because_o equal_o press_v on_o all_o side_n which_o it_o do_v the_o more_o easy_o sustain_v by_o reason_n of_o its_o round_a form_n in_o the_o nature_n of_o a_o continue_a arch._n and_o we_o find_v in_o experience_n that_o a_o round_a glass_n though_o but_o of_o equal_a thickness_n will_v bear_v a_o much_o great_a pressure_n from_o without_o than_o from_o within_o and_o more_o than_o if_o it_o be_v flat-sided_n and_o more_o if_o the_o pressure_n be_v of_o all_o side_n than_o if_o but_o in_o some_o only_o all_o which_o concur_v in_o the_o eggshell_n so_o situate_v but_o if_o press_v only_o upon_o one_o side_n a_o less_o pressure_n will_v break_v it_o i_o add_v also_o that_o though_o in_o perfect_a fluid_n there_o be_v no_o such_o arch_v yet_o in_o a_o heap_n of_o solid_n as_o that_o of_o wheat_n something_a there_o be_v of_o that_o nature_n and_o the_o more_o as_o those_o grain_n be_v big_a and_o convenient_o shape_v and_o may_v therefore_o help_v to_o bear_v the_o burden_n like_v as_o 4_o or_o 5_o leg_n in_o the_o table_n we_o mention_v if_o strong_a enough_o will_v supply_v the_o defect_n of_o one_o weak_a one_o which_o therefore_o be_v not_o break_v though_o not_o strong_a enough_o of_o itself_o to_o bear_v its_o part_n but_o the_o more_o any_o such_o heap_n approach_v to_o the_o nature_n of_o a_o fluid_a the_o less_o be_v there_o room_n for_o such_o arch_v and_o in_o perfect_a fluid_n none_o at_o all_o hence_o it_o be_v also_o that_o a_o sponge_n though_o light_a than_o water_n and_o flaccid_n also_o will_v not_o yet_o though_o fasten_v to_o the_o bottom_n of_o a_o vessel_n be_v crush_v together_o by_o the_o weight_n of_o the_o incumbent_a water_n because_o the_o water_n within_o its_o pore_n do_v bear_v out_o the_o side_n with_o as_o great_a a_o strength_n as_o that_o without_o will_v press_v they_o in_o and_o the_o like_a we_o see_v when_o the_o lung_n take_v out_o of_o animal_n be_v immerse_v in_o water_n and_o the_o same_o account_n serve_v for_o the_o pressure_n of_o air_n on_o animal_n the_o air_n within_o press_v as_o strong_o outward_a by_o its_o spring_n as_o that_o without_o press_v inward_a there_o be_v no_o hurt_n to_o the_o animal_n at_o all_o and_o contrariwise_a the_o pressure_n of_o the_o air_n into_o the_o mouth_n and_o throat_n do_v not_o break_v open_a his_o breast_n or_o belly_n because_o balance_v with_o as_o great_a a_o pressure_n without_o but_o if_o a_o hand_n or_o arm_n be_v put_v into_o the_o air-pump_n and_o the_o air_n about_o it_o pump_v out_o that_o there_o be_v a_o failure_n of_o the_o outward_a compression_n to_o balance_n that_o within_o the_o arm_n the_o spring_n of_o that_o within_o it_o will_v put_v the_o arm_n to_o a_o great_a torture_n as_o divers_a of_o this_o society_n have_v find_v by_o experience_n and_o many_o animal_n by_o that_o mean_n have_v be_v kill_v within_o the_o same_o pneumatick_a engine_n in_o a_o much_o short_a time_n than_o will_v have_v be_v for_o want_n of_o respiration_n only_o the_o like_a be_v see_v in_o the_o break_n of_o glass_n bubble_n hermetical_o seal_v and_o of_o lamb_n bladder_n in_o the_o same_o pneumatick_a engine_n upon_o the_o subtraction_n of_o the_o ambient_fw-la air_n as_o also_o the_o boil_a of_o warm_a water_n and_o the_o strange_a expansion_n of_o blood_n into_o bubble_n upon_o such_o
or_o a_o syphon_n invert_v fig._n 28_o 29._o the_o fluid_a at_o a_o by_o sink_v itself_o will_v raise_v that_o at_o b_o to_z the_o level_v le_z then_o in_o case_n the_o nose_n at_o b_o be_v not_o so_o high_a the_o liquor_n if_o not_o otherwise_o stop_v must_v needs_o run_v over_o and_o if_o any_o shall_v say_v the_o reason_n hereof_o be_v because_o the_o air_n at_o b_o fly_n away_o by_o its_o levity_n and_o the_o water_n follow_v to_o avoid_v a_o vacuity_n he_o will_v hardly_o be_v assent_v to_o by_o those_o who_o see_v a_o visible_a weight_n or_o force_n at_o a_o to_o over-press_a it_o and_o thrust_v it_o out_o and_o for_o the_o same_o reason_n if_o the_o nose_n or_o pipe_n before_o it_o come_v to_o the_o height_n of_o e_o be_v recurvate_a fig._n 30_o 31._o and_o turn_v down_o to_o o_o that_o which_o will_v have_v run_v over_o at_o b_o will_n now_o run_v out_o at_o o_o be_v thrust_v up_o to_o b_o by_o the_o weight_n of_o a_o and_o fall_v down_o from_o thence_o by_o its_o own_o weight_n but_o in_o case_n a_o be_v low_a than_o b_o fig._n 32._o and_o the_o fluid_a uniform_o heavy_a a_o will_v not_o be_v able_a to_o drive_v it_o up_o to_o b_o much_o less_o make_v it_o there_o run_v over_o or_o turn_v about_o to_o o_o but_o contrariwise_a if_o it_o be_v full_a to_o b_o this_o will_v praeponderate_v and_o raise_v that_o at_o a._n yet_o if_o ac_fw-la be_v a_o heavy_a fluid_n suppose_v quicksilver_n &_o cb_n a_o light_a as_o wine_n or_o water_n the_o effect_n will_v follow_v as_o before_o till_o the_o great_a height_n of_o cb_n do_v countervail_v the_o great_a heaviness_n of_o ac_fw-la and_o contrariwise_a if_o ac_fw-la be_v specifical_o light_a than_o cb_n fig._n 33._o suppose_v that_o water_n and_o this_o quicksilver_n then_o must_v that_o be_v in_o such_o proportion_n high_a than_o this_o or_o else_o it_o will_v not_o rise_v to_o b_o nor_o run_v out_o at_o o._n but_o if_o ac_fw-la be_v high_o than_o in_o such_o proportion_n the_o effect_n will_v follow_v from_o the_o praegravitation_n of_o a_o without_o have_v recourse_n to_o a_o fuga_fw-la vacui_fw-la and_o thus_o far_o the_o ancient_n will_v agree_v with_o we_o for_o they_o never_o fly_v to_o a_o fuga_fw-la vacui_fw-la so_o long_o as_o there_o be_v visible_a weight_n or_o force_n to_o thrust_v up_o the_o fluid_a but_o that_o which_o give_v occasion_n to_o introduce_v this_o notion_n of_o fuga_fw-la vacui_fw-la be_v but_o these_o two_o experiment_n and_o such_o as_o be_v reducible_a thereunto_o wherein_o for_o want_v of_o a_o force_n to_o raise_v liquid_n by_o way_n of_o trusion_n they_o have_v recourse_n to_o this_o of_o traction_n ne_fw-la detur_fw-la vacuum_fw-la the_o first_o that_o of_o suction_n in_o pump_n syringe_n and_o other_o the_o like_a occasion_n the_o other_o be_v that_o of_o a_o syphon_n whereby_o liquor_n be_v carry_v over_o considerable_a height_n above_o their_o level_n for_o if_o the_o nose_n of_o a_o syringe_n be_v immerse_v in_o water_n as_o at_o b_o fig._n 34._o and_o the_o handle_n or_o embolus_fw-la be_v draw_v back_o the_o water_n or_o other_o fluid_a will_v follow_v it_o from_o b_o into_z d_o which_o be_v contrary_a to_o the_o nature_n of_o a_o heavy_a body_n and_o no_o other_o force_n appear_v to_o thrust_v it_o up_o it_o be_v imagine_v that_o nature_n abhor_v a_o vacuum_n and_o this_o make_v the_o liquor_n rise_v contrary_a to_o its_o particular_a propension_n to_o which_o fuga_fw-la vacui_fw-la as_o it_o be_v wont_a to_o be_v call_v linus_n of_o late_a and_o some_o other_o after_o he_o have_v give_v the_o name_n funiculus_fw-la and_o the_o like_a be_v to_o be_v say_v of_o all_o sort_n of_o pump_n and_o other_o the_o like_a engine_n which_o draw_v water_n by_o way_n of_o suction_n and_o as_o to_o the_o syphon_n if_o the_o end_n c_o be_v immerse_v in_o water_n or_o other_o liquor_n fig._n 35._o though_o b_o the_o top_n of_o the_o syphon_n be_v much_o high_a than_o a_o the_o surface_n of_o the_o liquor_n yet_o if_o o_o be_v low_a than_o a_o though_o it_o will_v not_o of_o itself_o begin_v to_o run_v yet_o if_o by_o suction_n or_o otherwise_o it_o be_v set_v a_o run_a this_o current_n will_v continue_v till_o either_o a_o be_v sink_v so_o low_a as_o to_o let_v in_o air_n at_o c_o or_o be_v low_a than_o the_o outward_a orifice_n o._n the_o reason_n whereof_o say_v they_o since_o there_o appear_v not_o any_o force_n to_o thrust_v it_o up_o must_v needs_o be_v this_o boy_n flow_v out_o by_o its_o own_o weight_n if_o cb_n do_v not_o follow_v it_o contrary_a to_o the_o propension_n of_o its_o own_o gravity_n a_o vacuum_n must_v needs_o ensue_v which_o therefore_o they_o suppose_v nature_n do_v abhor_v for_o answer_v i_o say_v first_o there_o be_v no_o other_o foundation_n in_o nature_n to_o prove_v this_o abhorrence_n but_o only_o these_o experiment_n and_o this_o not_o otherwise_o know_v but_o be_v only_o invent_v as_o a_o expedient_a to_o serve_v a_o turn_n if_o we_o can_v otherwise_o solve_v the_o phaenomenon_n and_o show_v a_o force_n which_o they_o do_v not_o think_v of_o there_o will_v be_v no_o need_n of_o this_o expedient_a at_o all_o and_o this_o abhorrence_n must_v be_v either_o gratis_o dictum_fw-la without_o any_o cogent_a proof_n or_o some_o other_o evidence_n must_v be_v show_v for_o it_o than_o those_o who_o do_v introduce_v it_o be_v aware_a of_o for_o all_o the_o subsidiary_a proof_n of_o late_o invent_v be_v not_o the_o ground_n of_o introduce_v the_o opinion_n and_o therefore_o without_o dispute_v whether_o nature_n can_v or_o can_v admit_v a_o vacuum_n i_o shall_v only_o show_v that_o there_o be_v no_o need_n of_o that_o notion_n as_o to_o this_o business_n next_o that_o this_o fuga_fw-la vacui_fw-la be_v not_o the_o cause_n of_o water_n thus_o rise_v in_o a_o pump_n or_o syphon_n i_o thus_o argue_v for_o if_o so_o it_o ought_v to_o hold_v to_o any_o height_n whatever_o a_o pump_n for_o instance_n must_v draw_v water_n a_o hundred_o foot_n high_a and_o a_o syphon_n convey_v water_n over_o the_o high_a hill_n or_o tower_n for_o the_o argument_n equal_o hold_v whether_o the_o height_n of_o b_o be_v two_o foot_n or_o two_o hundred_o foot_n if_o boy_n flow_v out_o and_o cb_n not_o follow_v a_o vacuum_n must_v ensue_v equal_o in_o either_o case_n and_o the_o consequence_n of_o this_o argument_n be_v so_o clear_a that_o in_o confidence_n thereof_o the_o ancient_n do_v not_o doubt_v but_o that_o it_o will_v be_v so_o none_o that_o we_o know_v of_o till_o galilaeo_n time_n have_v ever_o question_v it_o or_o assign_v any_o determinate_a height_n beyond_o which_o a_o pump_n will_v not_o draw_v water_n or_o over_o which_o a_o syphon_n will_v not_o convey_v it_o and_o it_o be_v a_o surprise_a discovery_n and_o whole_o unexpected_a when_o about_o the_o end_n of_o the_o last_o century_n it_o be_v first_o find_v out_o by_o experience_n that_o water_n can_v not_o thus_o be_v draw_v high_a than_o about_o 34_o foot_n i_o say_v about_o 34_o foot_n not_o just_a so_o much_o because_o that_o alter_v with_o the_o temperature_n of_o the_o air._n when_o the_o air_n be_v very_a light_n it_o will_v not_o much_o exceed_v 32_o foot_n when_o very_o heavy_a it_o may_v reach_v 35_o foot_n which_o experiment_n alone_o do_v evident_o evince_v that_o the_o suppose_a fuga_fw-la vacui_fw-la be_v not_o of_o a_o infinite_a but_o of_o a_o determinate_a strength_n which_o put_v galileo_n upon_o the_o inquiry_n whether_o it_o be_v not_o from_o some_o other_o cause_n than_o fuga_fw-la vacui_fw-la that_o it_o will_v be_v draw_v so_o high_a but_o not_o high_o and_o he_o happy_o light_v on_o this_o hypothesis_n of_o the_o counter-gravitation_a of_o the_o incumbent_n air._n the_o same_o have_v be_v since_o improve_v by_o torricellio_n and_o other_o after_o he_o who_o rational_o argue_v that_o if_o such_o counter-gravitation_a of_o the_o air_n will_v countervail_v the_o weight_n of_o 34_o foot_n of_o water_n it_o ought_v in_o light_a liquor_n countervail_v a_o great_a height_n and_o a_o less_o height_n in_o heavy_a and_o find_v upon_o experiment_n that_o so_o it_o be_v if_o some_o little_a difference_n chance_n to_o be_v sometime_o discover_v it_o be_v to_o be_v account_v for_o from_o some_o different_a constitution_n of_o the_o air_n about_o we_o or_o other_o little_a accident_n too_o many_o to_o be_v here_o recount_v and_o particular_o that_o as_o water_n will_v be_v so_o raise_v about_o 34_o foot_n so_o quicksilver_n to_o the_o height_n of_o about_o 29_o inch_n and_o no_o more_o i_o mean_v 28_o 29_o or_o 30_o as_o the_o air_n temperature_n do_v vary_v which_o agree_v with_o the_o proportion_n of_o the_o specific_a weight_n of_o those_o liquid_n quicksilver_n be_v near_o upon_o 14_o time_n as_o heavy_a