the_o motion_n last_v also_o but_o when_o that_o cease_v the_o motion_n cease_v likewise_o and_o it_o be_v add_v that_o this_o quality_n can_v last_v always_o be_v in_o its_o nature_n so_o imperfect_a that_o it_o can_v last_v long_o beside_o it_o be_v object_v that_o experience_n show_v that_o all_o motion_n do_v cease_v little_a by_o little_a as_o appear_v in_o a_o wheel_n that_o have_v be_v violent_o agitate_a in_o a_o ball_n that_o have_v be_v roll_v on_o a_o billiard-table_n in_o a_o ball_n suspend_v and_o vibrate_v and_o in_o other_o innumerable_a body_n the_o motion_n of_o which_o do_v by_o little_a and_o little_o diminish_v and_o at_o last_o be_v quite_o extinguish_v vii_o a_o finite_a cause_n may_v have_v a_o effect_v that_o last_v always_o i_o say_v it_o be_v very_o easy_a to_o answer_v all_o these_o objection_n and_o many_o such_o other_o if_o any_o one_o will_v maintain_v that_o motion_n be_v a_o infinite_a effect_n because_o it_o last_v forever_o he_o must_v also_o say_v that_o rest_n will_v be_v a_o infinite_a effect_n if_o it_o thus_o last_v eternal_o and_o that_o consequent_o a_o finite_a cause_n not_o be_v able_a to_o have_v a_o infinite_a effect_n it_o must_v be_v say_v that_o after_o a_o man_n have_v put_v a_o body_n at_o rest_n this_o body_n can_v remain_v in_o that_o rest_n forever_o but_o that_o rest_n must_v at_o last_o cease_v and_o the_o body_n begin_v to_o move_v which_o be_v not_o consonant_a to_o reason_n there_o be_v a_o great_a difference_n between_o a_o infinite_a and_o a_o ever-during_a effect_n and_o if_o it_o be_v true_a that_o a_o finite_a cause_n can_v produce_v a_o infinite_a effect_n it_o be_v as_o true_a that_o a_o cause_n how_o bound_v soever_o it_o be_v may_v produce_v a_o ever-subsisting_a effect_n if_o it_o be_v not_o destroy_v by_o some_o new_a cause_n for_o if_o i_o make_v a_o square_a figure_n upon_o wax_n this_o figure_n will_v last_v always_o if_o nothing_o survene_v to_o spoil_v it_o or_o to_o destroy_v the_o wax_n itself_o so_o that_o it_o be_v not_o incongruous_a at_o all_o to_o say_v that_o if_o rest_v or_o motion_n be_v once_o produce_v in_o a_o body_n this_o rest_n or_o motion_n shall_v last_v without_o end_n if_o nothing_o come_v to_o destroy_v it_o viii_o this_o quality_n which_o be_v call_v impetuosity_n last_v always_o as_o to_o that_o quality_n which_o be_v pretend_v to_o be_v produce_v in_o the_o body_n by_o he_o that_o strike_v it_o it_o be_v all_o one_o to_o i_o whether_o it_o be_v believe_v to_o be_v so_o or_o not_o but_o this_o i_o say_v that_o if_o that_o quality_n be_v necessary_a it_o will_v last_v forever_o after_o it_o have_v be_v once_o produce_v and_o that_o it_o will_v never_o cease_v to_o be_v till_o some_o new_a cause_n destroy_v it_o and_o herein_o the_o sentiment_n of_o vasquez_n 1._o 2._o d._n 81._o c._n 2_o &_o 3._o be_v very_o remarkable_a when_o he_o teach_v general_o of_o all_o form_n substantial_a and_o accidental_a and_o particular_o of_o motion_n and_o impetuosity_n that_o if_o they_o can_v subsist_v one_o moment_n without_o need_v the_o influence_n of_o their_o first_o efficient_a cause_n they_o will_v last_v always_o until_o they_o be_v destroy_v by_o the_o production_n of_o a_o new_a contrary_a form_n if_o man_n will_v still_o persist_v in_o this_o opinion_n and_o say_v that_o this_o quality_n be_v so_o weak_a in_o its_o own_o nature_n that_o it_o destroy_v itself_o i_o do_v maintain_v that_o after_o this_o quality_n shall_v have_v be_v destroy_v the_o motion_n notwithstanding_o must_v continue_v for_o the_o reason_n already_o deliver_v in_o regard_n that_o motion_n can_v cease_v unless_o rest_v be_v produce_v a_o new_a but_o there_o must_v always_o be_v a_o positive_a cause_n to_o produce_v a_o new_a what_o effect_v soever_o it_o be_v whereas_o there_o need_v none_o such_o to_o make_v that_o subsist_v which_o be_v already_o in_o be_v and_o this_o be_v the_o true_a reason_n why_o a_o square_a figure_n make_v in_o wax_n will_v last_v eternal_o if_o god_n shall_v keep_v all_o external_a agent_n from_o destroy_v any_o thing_n in_o that_o wax_n because_o this_o square_a body_n of_o wax_n can_v not_o lose_v this_o figure_n unless_o another_o figure_n be_v produce_v and_o as_o a_o figure_n can_v begin_v to_o be_v a_o new_a unless_o there_o be_v some_o positive_a cause_n to_o produce_v it_o and_o we_o also_o suppose_v that_o there_o be_v none_o such_o in_o this_o case_n it_o must_v needs_o follow_v that_o this_o first_o figure_n which_o be_v already_o produce_v keep_v forever_o the_o possession_n of_o its_o existence_n it_o be_v the_o same_o thing_n with_o motion_n and_o although_o this_o pretend_a impetuosity_n cease_v to_o be_v yet_o the_o motion_n which_o be_v already_o produce_v be_v not_o therefore_o to_o cease_v also_o because_o there_o be_v no_o new_a cause_n produce_v rest_n and_o motion_n can_v cease_v but_o rest_n must_v be_v produce_v instead_o thereof_o ix_o the_o body_n which_o we_o move_v do_v cease_v to_o move_v because_o they_o be_v impede_v last_o when_o we_o see_v that_o body_n move_v by_o we_o do_v in_o a_o little_a time_n cease_v to_o move_v that_o prove_v nothing_o against_o we_o it_o be_v certain_a that_o those_o body_n meet_v with_o impediment_n to_o their_o motion_n whence_o we_o see_v that_o the_o more_o or_o the_o less_o we_o remove_v of_o those_o impediment_n the_o more_o or_o less_o do_v those_o motion_n continue_v thus_o a_o ball_n roll_v much_o long_o over_o a_o very_a smooth_a alley_n than_o in_o a_o rugged_a way_n a_o wheel_n turn_v much_o better_o if_o its_o axletree_n be_v slender_a and_o well_o turn_v than_o when_o it_o be_v big_a and_o irregular_a a_o stone_n be_v cast_v much_o far_o in_o the_o air_n than_o in_o water_n but_o i_o shall_v endeavour_v in_o the_o sequel_n of_o this_o discourse_n to_o explain_v how_o all_o these_o impediment_n do_v by_o little_a and_o little_o make_v the_o motion_n of_o body_n to_o cease_v x._o a_o demand_n for_o the_o safety_n of_o the_o follow_a demonstration_n all_o i_o have_v be_v just_a now_o deduce_v about_o the_o nature_n and_o perpetuity_n of_o motion_n be_v in_o a_o manner_n necessary_a for_o the_o understanding_n what_o i_o pretend_v to_o demonstrate_v in_o this_o discourse_n but_o as_o this_o question_n can_v never_o be_v handle_v so_o clear_o but_o that_o it_o will_v always_o be_v obnoxious_a to_o the_o cavil_n of_o disputant_n i_o foresee_v well_o enough_o that_o after_o all_o my_o reason_v it_o will_v doubtless_o so_o fall_v out_o that_o all_o will_v not_o be_v convince_v of_o what_o i_o shall_v have_v undertake_v to_o prove_v and_o beside_o not_o be_v willing_a to_o clash_v with_o any_o nor_o to_o leave_v ground_n to_o believe_v that_o i_o build_v my_o discourse_n upon_o a_o doubtful_a principle_n i_o declare_v that_o for_o the_o firmness_n of_o my_o demonstration_n i_o need_v not_o it_o shall_v be_v think_v that_o motion_n will_v in_o effect_n be_v perpetual_a so_o it_o be_v but_o allow_v i_o which_o no_o man_n can_v deny_v that_o motion_n once_o begin_v last_v at_o least_o for_o some_o time_n and_o continue_v the_o more_o uniform_o the_o less_o impediment_n there_o be_v to_o stop_v or_o diminish_v it_o let_v this_o continuance_n of_o motion_n be_v explain_v by_o the_o production_n of_o a_o impress_a quality_n or_o by_o a_o simple_a determination_n or_o by_o whatever_o you_o please_v it_o be_v indifferent_a to_o i_o i_o only_o demand_v it_o may_v be_v allow_v i_o to_o take_v this_o as_o a_o postulatum_fw-la of_o geometry_n that_o after_o a_o body_n be_v once_o move_v it_o continue_v to_o move_v for_o some_o time_n and_o that_o this_o time_n be_v considerable_a when_o there_o be_v nothing_o without_o able_a to_o stop_v or_o lessen_v the_o motion_n by_o the_o mean_n of_o which_o demand_v i_o hope_v that_o all_o the_o follow_a demonstration_n will_v be_v find_v of_o full_a force_n xi_o a_o body_n receive_v successive_o many_o determination_n remain_v only_o affect_v with_o the_o last_o a_o body_n not_o only_o persever_v in_o rest_n or_o motion_n according_a as_o it_o have_v once_o begin_v to_o be_v in_o either_o but_o it_o persist_v also_o in_o the_o same_o kind_n of_o motion_n and_o with_o the_o same_o degree_n of_o celerity_n in_o which_o it_o have_v be_v put_v for_o example_n if_o it_o have_v begin_v to_o move_v in_o a_o straight_a line_n eastward_o with_o one_o degree_n of_o celerity_n it_o continue_v to_o move_v with_o the_o same_o degree_n without_o ever_o recede_v a_o jot_n from_o the_o same_o line_n which_o be_v evident_a from_o the_o same_o reason_n i_o allege_v to_o prove_v the_o motion_n to_o last_v always_o but_o it_o be_v to_o be_v note_a that_o when_o a_o body_n have_v successive_o receive_v many_o different_a determination_n it_o remain_v
a_o discourse_n of_o local_a motion_n undertake_v to_o demonstrate_v the_o law_n of_o motion_n and_o withal_o to_o prove_v that_o of_o the_o seven_o rule_n deliver_v by_o m._n des-cartes_n on_o this_o subject_a he_o have_v mistake_v six_o by_o a._n m._n english_v out_o of_o french_a london_n print_v by_o w._n g._n and_o be_v to_o be_v sell_v by_o moses_n pitt_n at_o the_o white-hart_n in_o little-britain_n 1670._o the_o preface_n i_o pretend_v not_o to_o celebrate_v in_o this_o place_n the_o mechanic_n and_o to_o set_v forth_o the_o advantage_n which_o the_o knowledge_n of_o motion_n afford_v we_o it_o be_v sufficient_o know_v that_o all_o the_o production_n which_o come_v either_o from_o the_o industry_n of_o man_n or_o from_o the_o cause_n of_o nature_n be_v make_v no_o otherwise_o but_o by_o motion_n so_o that_o it_o be_v not_o possible_a to_o penetrate_v into_o the_o secret_n of_o nature_n nor_o to_o succeed_v in_o the_o invention_n and_o practice_n of_o art_n without_o the_o assistance_n of_o the_o mechanic_n that_o be_v without_o the_o knowledge_n of_o the_o law_n of_o motion_n neither_o do_v i_o undertake_v here_o to_o go_v through_o this_o whole_a subject_n it_o be_v too_o vast_a to_o be_v comprise_v in_o so_o brief_a a_o discourse_n as_o this_o be_v intend_v i_o have_v confine_v myself_o to_o what_o may_v be_v call_v the_o element_n of_o this_o knowledge_n and_o i_o insist_v particular_o on_o consider_v the_o communication_n which_o be_v make_v of_o motion_n in_o percussion_n it_o be_v true_a that_o this_o subject_n have_v be_v handle_v by_o very_o eminent_a man_n but_o i_o take_v it_o quite_o otherwise_o in_o hand_n i_o think_v than_o they_o have_v do_v for_o without_o make_v any_o particular_a hypothesis_n i_o make_v it_o my_o business_n to_o search_v in_o the_o very_a source_n of_o nature_n the_o cause_n of_o all_o the_o effect_n we_o find_v in_o motion_n and_o i_o undertake_v to_o give_v the_o demonstration_n of_o they_o which_o without_o suppose_v any_o experiment_n at_o all_o be_v only_o found_v upon_o incontrolable_a principle_n of_o pure_a metaphysic_n the_o design_n will_v doubtless_o appear_v bold_a to_o those_o who_o know_v the_o difficulty_n there_o be_v in_o thus_o prevent_v experiment_n and_o in_o prescribe_v to_o nature_n such_o law_n as_o she_o be_v afterward_o to_o observe_v it_o may_v also_o come_v to_o pass_v that_o the_o difference_n to_o be_v find_v between_o the_o rule_n which_o i_o endeavour_v to_o establish_v here_o and_o those_o which_o m._n des-cartes_n have_v lay_v down_o in_o his_o principle_n of_o physics_n will_v furnish_v matter_n to_o exercise_v the_o curiosity_n of_o those_o who_o love_v the_o philosophy_n of_o that_o author_n and_o engage_v they_o to_o make_v search_n wherein_o my_o paralogism_n may_v consist_v in_o regard_n that_o the_o ratiocination_n which_o i_o employ_v be_v so_o opposite_a to_o those_o which_o many_o have_v take_v hitherto_o for_o true_a demonstration_n for_o i_o advow_v that_o of_o the_o seven_o rule_n of_o motion_n which_o m._n des-cartes_n deliver_v there_o be_v but_o one_o only_a which_o agree_v with_o i_o so_o that_o either_o this_o philosopher_n have_v not_o hit_v aright_o in_o this_o point_n or_o i_o myself_o be_o fall_v into_o considerable_a error_n mean_a time_n i_o can_v be_v ignorant_a of_o what_o have_v be_v publish_v through_o all_o france_n touch_v the_o rule_n of_o percussion_n which_o have_v be_v propose_v by_o some_o famous_a mathematician_n of_o the_o royal_a academy_n of_o london_n and_o paris_n if_o there_o be_v honour_n in_o invent_v any_o thing_n new_a in_o science_n i_o do_v not_o contest_v with_o these_o person_n about_o that_o which_o they_o pretend_v to_o of_o have_v find_v the_o secret_a of_o the_o law_n of_o motion_n i_o willing_o and_o full_o yield_v it_o to_o they_o and_o i_o claim_v nothing_o therein_o yet_o this_o i_o can_v say_v that_o it_o be_v now_o three_o year_n that_o i_o give_v abroad_o all_o what_o i_o deliver_v here_o in_o this_o discourse_n and_o that_o if_o my_o rule_n be_v compare_v with_o they_o there_o may_v possible_o be_v find_v conformity_n enough_o to_o make_v man_n believe_v that_o i_o have_v light_v together_o with_o they_o upon_o the_o truth_n but_o there_o will_v also_o be_v find_v difference_n enough_o to_o make_v man_n judge_v that_o i_o have_v not_o learn_v it_o from_o they_o beside_o that_o they_o have_v do_v no_o more_o than_o mere_o to_o propose_v their_o rule_n without_o prove_v they_o whereas_o i_o undertake_v to_o demonstrate_v all_o those_o i_o advance_v and_o although_o m._n hugens_n have_v give_v we_o hope_n of_o publish_v short_o a_o book_n wherein_o he_o will_v prove_v all_o his_o rule_n yet_o not_o withstand_v without_o compare_v myself_o to_o so_o excellent_a a_o person_n i_o dare_v affirm_v that_o his_o method_n will_v be_v quite_o different_a from_o i_o forasmuch_o as_o he_o have_v already_o explain_v himself_o sufficient_o to_o give_v we_o to_o understand_v that_o his_o demonstration_n be_v ground_v upon_o particular_a hypothesis_n however_o i_o have_v already_o declare_v myself_o about_o the_o little_a pretention_n i_o have_v to_o the_o glory_n of_o pass_v for_o the_o inventor_n of_o these_o thing_n i_o leave_v it_o altogether_o to_o those_o gentleman_n and_o if_o they_o will_v allow_v i_o a_o share_n therein_o i_o shall_v receive_v it_o as_o a_o favour_n and_o take_v it_o kind_o that_o they_o will_v acknowledge_v i_o have_v hit_v upon_o their_o thought_n or_o at_o least_o not_o considerable_o shoot_v beside_o the_o mark._n a_o table_n of_o the_o head_n i._o a_o body_n be_v in_o itself_o indifferent_a to_o rest_n or_o motion_n pag._n 1._o ii_o if_o a_o body_n be_v once_o at_o rest_n it_o will_v ever_o remain_v therein_o pag._n 2._o iii_o and_o if_o it_o be_v once_o in_o motion_n it_o continue_v also_o to_o move_v always_o pag._n 3._o iv_o that_o rest_n be_v not_o a_o mere_a negation_n pag._n 4._o v._o that_o there_o be_v as_o much_o positive_a action_n in_o rest_n as_o in_o motion_n pag._n 5._o vi_o objection_n pag._n 8._o vii_o a_o finite_a cause_n may_v have_v a_o effect_v that_o last_v always_o pag._n 9_o viii_o this_o quality_n which_o be_v call_v impetuosity_n last_v always_o pag._n 11._o ix_o the_o body_n which_o we_o move_v do_v cease_v to_o move_v because_o they_o be_v impede_v pag._n 13._o x._o a_o demand_n for_o the_o safety_n of_o the_o follow_a demonstration_n pag._n 14._o xi_o a_o body_n receive_v successive_o many_o determination_n remain_v only_o affect_v with_o the_o last_o pag._n 16._o xii_o a_o free_a body_n can_v be_v determine_v to_o move_v in_o a_o curve_v line_n nor_o with_o unequal_a celerity_n pag._n 17._o xiii_o every_o body_n that_o move_v about_o a_o centre_n endeavour_n to_o recede_v from_o it_o pag._n 19_o fourteen_o the_o star_n can_v move_v of_o themselves_o pag._n 20._o xv._o how_o a_o body_n may_v be_v move_v circular_o pag._n 21._o xvi_o one_o body_n move_v against_o another_o body_n give_v it_o its_o whole_a motion_n pag._n 23._o xvii_o in_o the_o meeting_n of_o two_o body_n there_o be_v make_v a_o percussion_n which_o be_v mutual_a and_o equal_o receive_v in_o both_o pag._n 24._o xviii_o a_o move_a body_n meet_v with_o another_o body_n that_o be_v quiescent_n give_v it_o all_o its_o motion_n and_o remain_v itself_o moveless_a pag._n 26._o xix_o what_o be_v mean_v by_o absolute_a and_o respective_a velocity_n pag._n 28._o xx._n the_o percussion_n be_v as_o the_o respective_a velocity_n pag._n 29._o xxi_o two_o body_n meet_v one_o another_o turn_v back_o make_v a_o exchange_n of_o their_o velocity_n pag._n 31._o xxii_o two_o body_n move_v towards_o the_o same_o place_n continue_v after_o their_o encounter_n by_o exchange_v their_o velocity_n pag._n 33._o xxiii_o a_o hard_a body_n come_v to_o hit_v another_o body_n that_o can_v be_v shake_v be_v reflect_v with_o its_o whole_a motion_n pag._n 35._o xxiv_o the_o angle_n of_o reflection_n be_v equal_a to_o the_o angle_n of_o incidence_n pag_n 38._o xxv_o it_o may_v be_v imagine_v that_o tbe_n oblique_a motion_n be_v compose_v of_o two_o motion_n pag._n 40._o xxvi_o a_o remark_n upon_o the_o argument_n of_o p._n riccioli_n pag._n 42._o xxvii_o a_o remark_n upon_o some_o citadel_n pag._n 45._o xxviii_o a_o general_a rule_n of_o all_o percussion_n pag._n 46._o xxix_o there_o be_v always_o equal_a quantity_n of_o respective_a motion_n p._n 48._o xxx_o the_o midst_n of_o two_o body_n be_v always_o uniform_o move_v in_o a_o direct_a line_n pag._n 49._o xxxi_o all_o these_o rule_n be_v true_a whether_o the_o body_n be_v equal_a or_o not_o pag._n 50._o xxxii_o a_o body_n move_v in_o pleno_fw-la as_o free_o as_o in_o vacuo_fw-la pag._n 52._o xxxiii_o motion_n diminish_v little_a by_o little_a in_o the_o air._n pag._n 54._o xxxiv_o the_o percussion_n of_o equal_a body_n
be_v make_v in_o pleno_fw-la as_o in_fw-la vacuo_fw-la pag._n 56._o xxxv_o when_o the_o body_n be_v unequal_a the_o percussion_n be_v make_v in_o pleno_fw-la otherwise_o than_o in_o vacuo_fw-la pag._n 57_o xxxvi_o the_o percussion_n of_o unequal_a body_n can_v be_v reduce_v to_o one_o general_n rule_n pag._n 59_o xxxvii_o of_o refraction_n pag._n 61._o xxxviii_o the_o conclusion_n pag._n 62._o a_o appendix_n contain_v a_o review_n of_o this_o discourse_n make_v by_o the_o author_n himself_o pag._n 67._o a_o discourse_n of_o local_a motion_n i._o a_o body_n be_v in_o itself_o indifferent_a to_o rest_n or_o motion_n if_o we_o shall_v imagine_v that_o in_o the_o world_n there_o be_v nothing_o corporeal_a but_o one_o or_o two_o ball_n and_o sever_v from_o the_o same_o whatever_o may_v cause_v any_o kind_n of_o secret_a commerce_n whereby_o the_o one_o may_v attract_v or_o repel_v the_o other_o or_o if_o we_o shall_v consider_v such_o ball_n free_a from_o all_o kind_n of_o particular_a determination_n without_o levity_n without_o gravity_n in_o vacuo_fw-la or_o at_o least_o in_o a_o space_n altogether_o uniform_a where_o nothing_o be_v that_o may_v carry_v they_o rather_o this_o than_o that_o way_n or_o hinder_v they_o to_o move_v free_o if_o they_o shall_v happen_v to_o be_v propel_v towards_o a_o place_n then_o shall_v we_o conceive_v these_o ball_n to_o be_v absolute_o indifferent_a to_o touch_v one_o another_o or_o to_o be_v sever_v to_o be_v here_o or_o there_o forasmuch_o as_o they_o will_v find_v nothing_o more_o in_o one_o place_n than_o in_o another_o and_o consequent_o be_v equal_o indifferent_a for_o rest_n or_o motion_n ii_o if_o a_o body_n be_v once_o at_o rest_n it_o will_v ever_o remain_v therein_o and_o so_o if_o we_o further_o conceive_v that_o one_o of_o these_o ball_n be_v at_o rest_n have_v be_v put_v in_o that_o state_n by_o some_o cause_n that_o have_v power_n to_o stir_v or_o stop_v body_n we_o at_o the_o same_o time_n conceive_v it_o will_v eternal_o remain_v at_o rest_n if_o there_o be_v not_o some_o new_a cause_n displace_v it_o by_o put_v it_o into_o motion_n because_o this_o ball_n be_v of_o itself_o indifferent_a to_o rest_n or_o motion_n and_o be_v once_o determine_v to_o rest_n it_o be_v impossible_a it_o shall_v of_o itself_o quit_v that_o rest_n and_o fall_v to_o motion_n wherefore_o it_o must_v needs_o continue_v forever_o in_o that_o rest_n if_o nothing_o happen_v to_o make_v it_o change_v that_o state_n iii_o and_o if_o it_o be_v once_o in_o motion_n it_o continue_v also_o to_o move_v always_o by_o the_o same_o reason_n we_o must_v conceive_v that_o if_o one_o of_o these_o ball_n be_v put_v in_o motion_n by_o some_o cause_n or_o other_o it_o will_v continue_v to_o move_v forever_o if_o no_o new_a cause_n come_v to_o stop_v it_o because_o this_o ball_n be_v of_o itself_o indifferent_a to_o motion_n and_o rest_n and_o be_v once_o determine_v to_o motion_n it_o be_v impossible_a it_o shall_v determine_v itself_o to_o cease_v from_o that_o motion_n to_o take_v rest_n and_o so_o it_o must_v ever_o remain_v in_o this_o motion_n if_o nothing_o else_o come_v to_o stop_v it_o iv_o that_o rest_n be_v not_o a_o mere_a negation_n i_o find_v that_o we_o be_v general_o incline_v to_o consider_v rest_n as_o a_o cessation_n of_o action_n and_o to_o take_v motion_n for_o a_o positive_a action_n which_o we_o experiment_n in_o ourselves_o when_o we_o move_v ourselves_o or_o will_v move_v another_o body_n whereas_o we_o conceive_v a_o body_n to_o be_v at_o rest_n from_o the_o time_n that_o no_o body_n touch_v it_o or_o that_o there_o be_v no_o other_o cause_n which_o actual_o imprint_n in_o it_o this_o quality_n or_o this_o action_n necessary_a to_o motion_n and_o so_o it_o seem_v that_o although_o a_o body_n be_v once_o at_o rest_n remain_v therein_o forever_o yet_o it_o shall_v not_o follow_v that_o if_o it_o be_v once_o in_o motion_n it_o shall_v ever_o persist_v therein_o since_o that_o for_o to_o be_v move_v there_o be_v require_v a_o positive_a action_n but_o that_o rest_n be_v nothing_o else_o but_o a_o negation_n or_o a_o cease_v from_o action_n or_o motion_n v._o that_o there_o be_v as_o much_o positive_a action_n in_o rest_n as_o in_o motion_n but_o if_o the_o weight_n of_o our_o body_n which_o we_o must_v bear_v the_o rigidness_n of_o our_o limb_n which_o we_o must_v bend_v the_o agitation_n of_o the_o spirit_n which_o we_o must_v employ_v and_o many_o other_o thing_n make_v we_o feel_v some_o resistance_n and_o oblige_v we_o to_o use_v some_o force_n to_o overcome_v these_o impediment_n we_o can_v draw_v from_o thence_o any_o sequel_n against_o our_o hypothesis_n in_o which_o we_o suppose_v there_o be_v no_o impediment_n neither_o of_o gravity_n nor_o of_o particular_a inclination_n nor_o of_o any_o body_n resist_v from_o without_o in_o this_o case_n it_o be_v manifest_a that_o there_o need_v no_o more_o action_n for_o motion_n than_o for_o rest_n and_o that_o for_o the_o rest_n of_o a_o body_n it_o be_v not_o less_o requisite_a it_o shall_v be_v put_v at_o rest_n than_o it_o be_v necessary_a for_o its_o motion_n that_o it_o shall_v be_v put_v into_o it_o and_o indeed_o if_o we_o consider_v well_o the_o nature_n of_o rest_n and_o motion_n we_o shall_v find_v that_o motion_n may_v as_o well_o be_v call_v a_o cessation_n of_o rest_n as_o rest_v a_o cessation_n of_o motion_n or_o rather_o we_o shall_v find_v that_o both_o be_v something_o positive_a in_o regard_n that_o motion_n be_v a_o state_n by_o which_o a_o body_n correspond_v successive_o â—o_o many_o place_n or_o a_o pass_a presence_n or_o a_o sequel_n of_o divers_a presence_n in_o divers_a place_n as_o rest_n be_v a_o state_n by_o which_o a_o body_n always_o correspond_v to_o one_o and_o the_o same_o place_n or_o one_o and_o the_o same_o presence_n in_o one_o and_o the_o same_o place_n so_o that_o rest_v as_o well_o as_o motion_n be_v a_o state_n or_o a_o presence_n but_o differ_v in_o this_o that_o rest_n be_v a_o state_n of_o consistency_n and_o a_o constant_a presence_n always_o keep_v to_o be_v the_o same_o whereas_o motion_n be_v a_o change_a state_n and_o a_o transitory_a presence_n now_o in_o what_o manner_n soever_o these_o constant_a or_o pass_a presence_n be_v consider_v if_o there_o be_v any_o action_n or_o any_o power_n or_o any_o kind_n of_o cause_n in_o the_o body_n which_o be_v to_o produce_v this_o consecution_n of_o divers_a presence_n in_o motion_n there_o be_v no_o less_o action_n or_o force_n necessary_a in_o rest_n to_o preserve_v the_o same_o presence_n in_o regard_n that_o to_o preserve_v a_o thing_n be_v to_o produce_v it_o continual_o it_o be_v therefore_o evident_a that_o after_o the_o presence_n have_v be_v produce_v by_o a_o body_n in_o the_o first_o instant_n i_o speak_v in_o the_o sense_n of_o those_o who_o hold_v that_o there_o be_v a_o true_a production_n of_o these_o presence_n it_o must_v needs_o be_v also_o produce_v a_o new_a in_o the_o instant_n follow_v by_o the_o same_o body_n to_o make_v it_o remain_v quiescent_n but_o methinks_v there_o be_v in_o that_o as_o much_o action_n and_o as_o much_o power_n as_o there_o be_v for_o the_o produce_v in_o the_o second_o instant_n a_o new_a presence_n instead_o of_o reproduce_v the_o first_o nec_fw-la minor_fw-la est_fw-la virtus_fw-la quà m_fw-la quaerere_fw-la parta_fw-la tueri_fw-la so_o that_o whether_o there_o be_v to_o be_v produce_v every_o instant_n a_o new_a presence_n for_o motion_n or_o reproduced_a the_o same_o presence_n for_o rest_n it_o will_v always_o amount_v to_o the_o same_o and_o a_o body_n will_v have_v no_o less_o work_n to_o preserve_v to_o itself_o this_o same_o presence_n and_o to_o remain_v quiescent_n than_o to_o produce_v new_a presence_n and_o conserve_v itself_o in_o motion_n whence_o it_o be_v to_o be_v conclude_v that_o as_o a_o body_n from_o the_o very_a time_n it_o have_v be_v once_o determine_v to_o rest_n be_v sufficient_o determine_v always_o to_o keep_v itself_o in_o the_o same_o presence_n so_o also_o from_o the_o very_a moment_n it_o have_v be_v once_o determine_v to_o motion_n it_o be_v sufficient_o determine_v always_o to_o produce_v new_a presence_n and_o so_o to_o move_v itself_o without_o cease_v vi_o objection_n i_o shall_v not_o stay_v to_o answer_v all_o the_o cavil_v scruple_n that_o may_v be_v cast_v in_o upon_o this_o subject_a see_v they_o be_v easy_a enough_o to_o resolve_v for_o instance_n it_o be_v say_v that_o a_o finite_a cause_n can_v produce_v a_o infinite_a effect_n and_o that_o this_o motion_n will_v be_v infinite_a since_o it_o will_v last_v forever_o it_o be_v further_o allege_v that_o whoever_o move_v a_o body_n impress_v therein_o a_o certain_a quality_n call_v impetuosity_n and_o that_o as_o long_o as_o this_o quality_n last_v
vacuo_fw-la whence_o it_o appear_v that_o those_o who_o will_v prove_v the_o necessity_n of_o a_o vacuum_n from_o motion_n do_v not_o reason_n well_o xxxiii_o motion_n diminish_v little_a by_o little_a in_o the_o air._n but_o if_o the_o hard_a body_n be_v in_o a_o spongious_a liquor_n capable_a of_o compression_n or_o if_o this_o liquor_n be_v not_o so_o well_o bound_v in_o but_o that_o the_o extrimety_n will_v yield_v a_o little_a then_o the_o motion_n will_v not_o be_v perpetual_a but_o diminish_v by_o degree_n and_o be_v at_o last_o quite_o extinct_a for_o the_o hard_a body_n will_v find_v more_o resistance_n by_o the_o anteriour_a part_n of_o the_o liquor_n than_o it_o will_v receive_v of_o impulse_n by_o the_o posteriour_a because_o the_o liquor_n which_o be_v before_o be_v compress_v or_o the_o extremity_n yield_v the_o communication_n of_o the_o impression_n can_v be_v make_v perfect_o and_o so_o the_o posteriour_a part_n of_o the_o liquor_n will_v not_o be_v so_o much_o thrust_v as_o the_o anteriour_a and_o consequent_o will_v not_o so_o much_o thrust_v the_o hard_a body_n as_o the_o anteriour_a one_o retard_v it_o and_o it_o be_v for_o this_o reason_n that_o all_o the_o motion_n cease_v in_o the_o air_n and_o water_n or_o in_o other_o liquor_n because_o it_o be_v certain_a that_o the_o air_n be_v spongious_a and_o easy_o compress_v and_o that_o the_o liquor_n be_v not_o bound_v but_o by_o the_o air_n when_o they_o be_v abroad_o or_o at_o least_o by_o the_o side_n of_o some_o vessel_n that_o can_v yield_v and_o bend_v a_o little_a for_o we_o know_v by_o certain_a experience_n that_o glass_n vessel_n will_v stretch_v and_o even_o those_o of_o iron_n and_o brass_n will_v bend_v to_o the_o stroke_n make_v upon_o they_o xxxiv_o the_o percussion_n of_o equal_a body_n be_v make_v in_o pleno_fw-la as_o in_fw-la vacuo_fw-la the_o percussion_n that_o be_v make_v of_o body_n thus_o move_v in_o liquor_n differ_v in_o something_o from_o those_o that_o be_v make_v in_o vacuo_fw-la to_o understand_v the_o cause_n thereof_o we_o be_v to_o note_v that_o when_o a_o hard_a body_n be_v move_v in_o a_o liquor_n it_o also_o communicate_v its_o motion_n to_o the_o same_o liquor_n in_o such_o a_o manner_n that_o it_o move_v also_o in_o follow_v the_o hard_a body_n so_o as_o to_o divide_v itself_o and_o to_o open_v before_o and_o to_o follow_v and_o close_v itself_o after_o the_o body_n and_o if_o the_o body_n by_o any_o accident_n shall_v come_v to_o lose_v its_o motion_n yet_o the_o liquor_n be_v thus_o determine_v to_o move_v will_v give_v again_o to_o that_o body_n its_o motion_n and_o carry_v it_o away_o with_o itself_o in_o some_o such_o manner_n as_o river_n carry_v away_o with_o they_o the_o float_a wood._n if_o therefore_o a_o body_n come_v to_o hit_v another_o equal_a to_o it_o the_o phoenomena_fw-la will_v happen_v as_o in_o vacuo_fw-la because_o these_o two_o equal_a body_n be_v encompass_v with_o the_o same_o quantity_n of_o liquor_n as_o much_o as_o the_o liquor_n of_o the_o body_n percuss_v hinder_v this_o same_o body_n percuss_v from_o move_v free_o so_o much_o a_o equal_a quantity_n of_o liquor_n which_o be_v about_o the_o body_n percutient_fw-la drive_v also_o anew_o the_o percutient_fw-la as_o well_o as_o the_o percussed_a thus_o their_o motion_n after_o the_o percussion_n will_v be_v make_v as_o in_o vacuo_fw-la forasmuch_o as_o the_o resistance_n of_o the_o liquor_n from_o the_o body_n percuss_v be_v precise_o recompense_v by_o the_o impulsion_n of_o the_o liquor_n from_o the_o body_n percutient_fw-la xxxv_o when_o the_o body_n be_v unequal_a the_o percussion_n be_v make_v in_o pleno_fw-la otherwise_o than_o in_o vacuo_fw-la but_o if_o the_o body_n percutient_fw-la be_v great_a it_o must_v needs_o receive_v not_o so_o great_a a_o effect_n from_o the_o percussion_n as_o the_o other_o because_o it_o be_v carry_v away_o with_o more_o violence_n by_o the_o liquor_n which_o environ_n it_o for_o we_o see_v that_o a_o beam_n carry_v away_o by_o the_o stream_n of_o a_o river_n have_v much_o more_o effect_n when_o it_o come_v to_o hit_v against_o a_o bridge_n or_o a_o mill_n than_o a_o stick_n will_v have_v be_v carry_v down_o by_o the_o same_o river_n although_o the_o beam_n shall_v not_o move_v swift_a than_o the_o stick_n and_o that_o because_o the_o beam_n come_v to_o hit_v be_v also_o carry_v by_o the_o great_a quantity_n of_o water_n surround_v it_o whereas_o the_o stick_n be_v but_o little_a so_o by_o reason_n of_o the_o small_a space_n it_o take_v up_o and_o of_o the_o little_a water_n by_o which_o it_o be_v carry_v away_o thus_o therefore_o if_o the_o little_a body_n be_v at_o rest_n and_o the_o great_a come_v to_o hit_v it_o this_o great_a by_o communicate_v its_o motion_n to_o the_o small_a will_n not_o so_o be_v stop_v as_o to_o become_v moveless_a as_o it_o will_v do_v in_o vacuo_fw-la but_o it_o will_v continue_v to_o move_v and_o to_o follow_v though_o more_o slow_o on_o the_o contrary_a if_o the_o great_a one_o be_v quiescent_n the_o small_a after_o it_o shall_v have_v hit_v the_o other_o and_o communicate_v to_o it_o a_o part_n of_o its_o motion_n will_v be_v reflect_v lose_v a_o part_n of_o its_o velocity_n and_o from_o all_o this_o it_o appear_v that_o aristotle_n be_v not_o so_o much_o to_o be_v blame_v as_o some_o pretend_v when_o to_o explicate_v the_o cause_n of_o the_o continuation_n of_o the_o motion_n we_o see_v he_o have_v make_v use_n of_o the_o medium_n that_o be_v of_o the_o liquid_a substance_n wherein_o our_o body_n be_v move_v xxxvi_o the_o percussion_n of_o unequal_a body_n can_v be_v reduce_v to_o one_o general_n rule_n to_o determine_v the_o excess_n which_o there_o may_v be_v in_o the_o resistance_n or_o in_o the_o great_a impression_n of_o these_o unequal_a body_n i_o esteem_v a_o thing_n not_o to_o be_v undertake_v at_o least_o if_o we_o consider_v the_o body_n such_o as_o we_o have_v they_o among_o we_o because_o that_o depend_v from_o the_o resistance_n make_v by_o the_o liquid_a body_n wherein_o the_o hard_a body_n we_o see_v be_v move_v from_o the_o facility_n they_o have_v to_o be_v condense_v or_o rarify_v and_o from_o many_o other_o thing_n that_o can_v be_v know_v to_o we_o no_o more_o than_o a_o infinity_n of_o other_o impediment_n the_o combination_n whereof_o may_v infinite_o diversify_v all_o the_o effect_n of_o the_o percussion_n only_o i_o may_v say_v that_o make_v a_o certain_a hypothesis_n which_o appear_v natural_a enough_o it_o may_v be_v show_v by_o the_o precedent_a rule_n that_o the_o percussion_n of_o body_n unequal_a shall_v be_v after_o the_o manner_n deliver_v by_o monsieur_n hugens_n in_o the_o late_a 867._o late_a publish_a march_v 18._o 1669._o in_o french_a and_o insert_v also_o in_o the_o philosophical_a transaction_n numb_a 46._o pag._n 927._o which_o rule_v of_o motion_n be_v conform_v to_o those_o of_o dr._n christ_n wren_n print_v in_o the_o transaction_n numb_a 43._o pag._n 867._o journal_n des_n scavans_n but_o i_o shall_v not_o stay_v long_o upon_o that_o i_o may_v possible_o meet_v with_o another_o opportunity_n to_o discourse_v more_o ample_o of_o it_o xxxvii_o of_o refraction_n there_o appear_v also_o from_o what_o i_o have_v be_v explain_v the_o reason_n of_o the_o refraction_n that_o be_v make_v when_o a_o hard_a body_n pass_v out_o of_o one_o liquor_n into_o another_o of_o different_a consistence_n for_o if_o the_o hard_a body_n pass_v out_o of_o a_o more_o free_a liquor_n into_o one_o that_o be_v less_o so_o it_o will_v lose_v somewhat_o of_o its_o velocity_n in_o the_o passage_n find_v more_o resistance_n in_o the_o liquor_n which_o be_v before_o than_o it_o feel_v itself_o thrust_v by_o that_o which_o follow_v and_o so_o the_o refraction_n will_v be_v make_v by_o recede_v from_o the_o perpendicular_a on_o the_o contrary_a if_o the_o body_n pass_v out_o of_o a_o more_o impede_a liquor_n into_o another_o more_o free_a the_o refraction_n will_v be_v make_v by_o approach_v to_o the_o perpendicular_a and_o the_o body_n will_v increase_v its_o velocity_n in_o the_o passage_n because_o it_o be_v thrust_v more_o by_o the_o liquor_n which_o follow_v than_o it_o be_v detain_v by_o that_o which_o be_v find_v before_o and_o it_o be_v of_o this_o augmentation_n of_o velocity_n which_o i_o think_v no_o body_n have_v as_o yet_o give_v the_o reason_n of_o i_o shall_v not_o note_v the_o measure_n of_o these_o refraction_n because_o that_o have_v be_v do_v by_o other_o and_o their_o demonstration_n may_v be_v very_o well_o accommodate_v to_o the_o thing_n here_o by_o i_o advance_v nor_o do_v i_o speak_v in_o this_o place_n of_o the_o refraction_n of_o light_n because_o i_o believe_v that_o that_o be_v make_v quite_o otherwise_o that_o be_v by_o cause_n and_o mean_n altogether_o different_a as_o