practicable_a way_n for_o seaman_n yet_o mention_v when_o the_o theory_n of_o the_o moon_n motion_n be_v better_a know_v mr._n f._n have_v ingenious_o write_v to_o this_o purpose_n in_o his_o doctrine_n of_o the_o sphere_n annex_v to_o sir_n ionas_n moor_n system_n mathematics_n to_o which_o i_o advise_v you_o it_o be_v say_v that_o the_o moon_n move_v swift_a at_o new_a and_o full_a then_o at_o quarter_n to_o find_v the_o moon_n place_n by_o observation_n the_o most_o ingenious_a mathematical_a way_n be_v by_o take_v her_o distance_n from_o two_o know_a fix_a star_n see_v mr._n seller_n practical_a navigation_n the_o doctrine_n of_o the_o sphere_n problem_n 20._o but_o few_o seaman_n understand_v the_o affection_n and_o solution_n of_o spherical_a triangle_n that_o way_n be_v tedious_a and_o troublesome_a i_o know_v seaman_n care_v not_o to_o take_v so_o much_o pain_n beside_o the_o trouble_n of_o find_v the_o moon_n parallax_n and_o contrive_v instrument_n for_o take_v her_o exact_a distance_n from_o fix_a star_n the_o moon_n place_n may_v be_v find_v geometrical_o by_o scale_n and_o compass_n or_o on_o large_a map_n of_o the_o fix_a star_n first_o know_v her_o distance_n from_o any_o two_o know_a star_n in_o that_o map_n but_o a_o easy_a way_n be_v if_o we_o can_v contrive_v a_o instrument_n to_o take_v her_o difference_n of_o longitude_n from_o any_o fix_a star_n at_o one_o distance_n which_o i_o think_v not_o impossible_a especial_o when_o she_o be_v near_o the_o meridian_n or_o nonagesima_fw-la and_o then_o be_v the_o best_a time_n of_o observe_v illuminatio_fw-la lunae_fw-la per_fw-la solem._n see_v mr._n seller_n his_o atlas_n coelestibus_fw-la in_o the_o figure_n take_v from_o p._n gassendi_n institutio_fw-la astronomia_fw-la lib._n 2_o cap._n 26._o etc._n etc._n the_o moon_n be_v a_o round_a body_n and_o receive_v its_o light_n from_o the_o sun_n it_o follow_v that_o always_o one_o half_a of_o it_o yea_o somewhat_o more_o must_v be_v enlighten_v by_o he_o for_o see_v that_o the_o sun_n exceed_v the_o moon_n in_o bigness_n and_o that_o the_o big_a sphere_n always_o enlighten_v above_o half_a the_o less_o it_o do_v follow_v that_o above_o one_o half_a of_o the_o body_n of_o the_o moon_n must_v always_o be_v illuminate_v and_o see_v that_o the_o moon_n alter_v her_o position_n and_o in_o run_v about_o the_o earth_n do_v various_o face_n the_o sun_n it_o must_v needs_o be_v that_o according_a to_o its_o various_a access_n to_o or_o recess_n of_o the_o sun_n less_o or_o more_o of_o the_o illuminate_v half_a will_v appear_v to_o we_o which_o variation_n of_o her_o appearance_n be_v common_o call_v her_o phase_n the_o moon_n be_v never_o less_o enlighten_v then_o when_o she_o be_v at_o the_o full_a or_o in_o opposition_n with_o the_o sun_n because_o when_o she_o be_v full_a only_a that_o part_n towards_o we_o be_v enlighten_v whereas_o when_o new_a or_o in_o conjunction_n with_o the_o sun_n she_o be_v whole_o illuminate_v that_o part_n which_o be_v then_o towards_o we_o be_v enlighten_v by_o the_o earth_n and_o the_o other_o part_n that_o be_v turn_v from_o we_o by_o the_o sun_n for_o the_o moon_n do_v not_o only_o borrow_v her_o light_n from_o the_o sun_n but_o receive_v some_o weak_a illustration_n from_o the_o earth_n because_o the_o earth_n be_v a_o opake_v body_n must_v of_o necessity_n reflect_v part_n of_o her_o receive_a light_n and_o forasmuch_o as_o the_o earth_n be_v big_a than_o the_o moon_n consequent_o more_o light_a must_v be_v derive_v from_o the_o earth_n to_o the_o moon_n then_o from_o the_o moon_n to_o the_o earth_n this_o be_v confirm_v by_o experience_n because_o this_o secondary_a light_n as_o galilaeus_fw-la call_v it_o after_o the_o first_o quarter_n quite_o vanish_v by_o reason_n of_o the_o moon_n be_v too_o far_o distant_a and_o without_o the_o bound_n to_o which_o the_o reflect_a beam_n of_o the_o earth_n reach_v le_fw-fr grands_fw-fr body_n of_o philosophy_n see_v fig._n 30._o part_n 5._o chap._n 20._o now_o if_o the_o difference_n of_o the_o moon_n phase_n or_o the_o quantity_n of_o her_o illumination_n by_o the_o sun_n be_v mensurable_a by_o instrument_n than_o this_o method_n may_v happen_v to_o prove_v good_a for_o find_v the_o longitude_n in_o the_o ph._n tr_fw-la n._n 29._o p_o 451._o be_v a_o description_n of_o a_o instrument_n for_o divide_v a_o foot_n into_o many_o thousand_o part_n and_o thereby_o measure_v the_o diameter_n of_o the_o planet_n to_o great_a exactness_n etc._n etc._n also_o see_v ph._n tr_fw-la n._n 21._o p._n 373._o concern_v a_o way_n for_o take_v the_o diameter_n of_o the_o planet_n and_o for_o know_v the_o parallax_n of_o the_o moon_n etc._n etc._n the_o consideration_n hereof_o i_o humble_o recommend_v to_o the_o ingenious_a more_o especial_o to_o the_o royal_a society_n of_o london_n i_o have_v almost_o forget_v i_o desire_v you_o to_o take_v notice_n that_o one_o good_a map_n of_o the_o fix_a star_n may_v serve_v for_o ever_o without_o alteration_n save_o that_o it_o may_v decay_v in_o time_n which_o bad_a usage_n or_o a_o little_a alteration_n of_o the_o sun_n declination_n which_o be_v scarce_o worth_a our_o notice_n in_o one_o hundred_o year_n provide_v that_o either_o the_o equinoctial_a or_o the_o ecliptic_a line_n in_o those_o map_n be_v make_v to_o slide_v upon_o it_o and_o then_o it_o be_v only_o slide_v they_o a_o little_a every_o year_n according_a to_o the_o praecession_n of_o the_o aequinox_n the_o like_a aught_o to_o be_v consider_v in_o celestial_a globe_n and_o planisphere_n also_o one_o good_a table_n of_o the_o fix_a star_n place_n may_v serve_v for_o ever_o by_o add_v only_o the_o praecession_n of_o the_o aequinox_n chap._n vii_o longitude_n by_o jupiter_n satellite_n galilaeus_n in_o the_o year_n 1610_o the_o seven_o of_o january_n at_o the_o first_o hour_n of_o the_o night_n discover_v 4_o less_o planet_n about_o jupiter_n which_o like_o so_o many_o little_a moon_n be_v whirl_v round_o he_o those_o of_o they_o which_o be_v near_a to_o jupiter_n move_v more_o swift_o than_o those_o which_o be_v more_o remote_a the_o revolution_n of_o those_o secondary_a planet_n be_v thus_o calculate_v the_o innermost_a satellite_fw-la revolve_v to_o the_o sun_n in_o 1_o d_o 18_o h_o 28′_n 36″_n so_o precise_o that_o in_o 100_o year_n the_o difference_n be_v not_o sensible_a the_o period_n of_o the_o revolution_n of_o the_o other_o three_o satellite_n to_o jupiter_n shade_n be_v as_o follow_v  _fw-fr d_o h_o ′_o ″_o ‴_o period_n secundi_fw-la 3_o 13_o 17_o 54_o 3_o period_n tertii_fw-la 7_o 3_o 59_o 39_o 22_o period_n quaerti_n 16_o 18_o 5_o 6_o 50_o the_o attendant_n of_o jupiter_n whenever_o they_o enter_v the_o verge_n of_o his_o shadow_n do_v suffer_v a_o eclipse_n after_o the_o same_o manner_n as_o the_o moon_n do_v when_o she_o dip_v in_o the_o shadow_n of_o the_o earth_n and_o be_v total_o deprive_v of_o light_n as_o be_v opake_v body_n which_o borrow_v their_o light_n from_o the_o sun_n the_o 3_o first_o of_o these_o in_o every_o revolution_n produce_v 4_o eclipse_n the_o first_o when_o the_o satelles_fw-la enter_v into_o the_o rim_z of_o jupiter_n the_o second_o when_o the_o shadow_n of_o the_o satelles_fw-la do_v darken_v the_o rim_z of_o the_o say_a planet_n the_o three_o when_o the_o upper_a part_n of_o jupiter_n at_o his_o elongation_n from_o we_o do_v hide_v the_o satellite_n and_o the_o four_o when_o the_o satelles_fw-la dip_v in_o the_o shadow_n of_o jupiter_n so_o as_o that_o the_o first_o satelles_fw-la within_o the_o space_n of_o 7_o day_n do_v effect_n 16_o eclipse_n the_o second_o 8_o the_o three_o 4_o so_o that_o all_o of_o they_o together_o produce_v 28_o eclipse_n the_o four_o after_o that_o he_o have_v reach_v the_o nodes_fw-la do_v make_v 4_o eclipse_n in_o 17_o day_n but_o when_o near_o his_o bound_n he_o never_o suffer_v a_o defect_n of_o his_o light_n because_o his_o latitude_n be_v so_o large_a that_o he_o never_o touch_v the_o rim_z of_o jupiter_n or_o reach_v his_o shadow_n these_o eclipse_n be_v of_o great_a use_n in_o order_n to_o the_o determine_n of_o the_o longitude_n of_o place_n le_z grand_n philosophy_n but_o the_o eclipse_n for_o our_o purpose_n be_v only_o the_o immersion_n or_o emersion_n of_o the_o satellite_n in_o the_o verge_n of_o jupiter_n shade_n many_o there_o be_v who_o prefer_v this_o phaenomenon_n before_o other_o because_o the_o satellite_n of_o jupiter_n have_v no_o sensible_a parallax_n and_o in_o every_o position_n of_o jupiter_n above_o the_o horizon_n in_o the_o night_n when_o wether_n permit_v be_v convenient_o to_o be_v observe_v with_o a_o telescope_n of_o 12_o or_o 15_o foot_n long_o a_o fine_a dance_a instrument_n indeed_o at_o sea_n especial_o in_o a_o gale_n of_o wind_n than_o not_o manageable_a to_o look_v through_o a_o tube_n of_o 15_o or_o 18_o foot_n
do_v i_o reflect_v i_o expect_v no_o thanks_o for_o my_o pain_n but_o to_o be_v reflect_v on_o again_o as_o harrison_n whimsy_n or_o the_o like_a i_o pray_v forsooth_o how_o many_o such_o whimsical_a invention_n can_v my_o countryman_n boast_v of_o that_o they_o have_v not_o borrow_a i_o have_v often_o hear_v they_o boast_v of_o drake_n and_o candish_n sail_v the_o world_n about_o but_o not_o a_o word_n of_o the_o portuguese_n that_o show_v the_o way_n if_o any_o envious_a person_n pretend_v i_o have_v borrow_v most_o of_o my_o book_n may_v he_o be_v oblige_v to_o quote_v the_o author_n where_o i_o have_v not_o i_o advise_v some_o mathematic_a bookseller_n for_o his_o and_o the_o public_a good_a to_o re-print_n mr._n street_n astr_n car._n with_o its_o appendix_n and_o calendar_n and_o to_o add_v a_o new_a and_o more_o easy_a theory_n of_o the_o moon_n motion_n by_o mr._n halley_n or_o mr._n newton_n table_n of_o jupiter_n satellite_n and_o a_o catalogue_n of_o fix_a star_n and_o their_o true_a place_n by_o mr._n flamstead_n if_o they_o be_v to_o be_v have_v if_o not_o to_o borrow_v from_o mr._n cassini_n and_o hevelius_n some_o of_o the_o ordinary_a mathematician_n may_v hate_v to_o be_v outdo_v by_o a_o tarpolin_n if_o they_o have_v aught_o to_o say_v against_o he_o it_o be_v because_o his_o practice_n and_o experience_n may_v prove_v he_o to_o be_v a_o more_o competent_a artist_n in_o navigation_n then_o themselves_o if_o i_o have_v commit_v some_o blunder_n the_o name_n of_o tar_n and_o the_o novelty_n of_o the_o subject_a may_v excuse_v i_o to_o the_o judicious_a your_o friend_n and_o servant_n edward_n harrison_n the_o content_n chap._n i._n concern_v a_o first_o meridian_n pag._n 1._o chap._n ii_o a_o definition_n of_o longitude_n chap._n iii_o a_o definition_n of_o time_n and_o aequation_n of_o natural_a day_n chap._n iu._n of_o automata_n or_o horological_a self-mover_n chap._n v._n of_o or_o concern_v longitude_n by_o magnetic_a variation_n chap._n vi_o longitude_n by_o the_o moon_n motion_n by_o her_o conjunction_n or_o eclipse_n and_o apulse_n to_o fix_a star_n of_o her_o illumination_n by_o the_o sun_n chap._n vii_o longitude_n by_o jupiter_n satellite_n chap._n viii_o conclusion_n idea_n longitudinis_fw-la be_v a_o brief_a definition_n of_o the_o best_a know_a axiom_n for_o find_v the_o longitude_n etc._n etc._n chap._n i._o concern_v a_o first_o meridian_n divers_a be_v the_o opinion_n of_o the_o ancient_n about_o the_o middle_n and_o centre_n of_o this_o world_n before_o christianity_n the_o european_a heathen_n esteem_v those_o place_n as_o the_o centre_n of_o this_o world_n where_o their_o god_n be_v chief_o worship_v as_o at_o delphos_n for_o apollo_n oracle_n at_o ephesus_n for_o diana_n temple_n etc._n etc._n the_o primitive_a christian_n believe_v jerusalem_n to_o be_v the_o middle_n of_o the_o world_n ptolemy_n who_o live_v anno_fw-la christi_fw-la 138._o begin_v his_o longitude_n at_o the_o most_o western_a part_n as_o he_o think_v at_o the_o fortunate_a island_n now_o call_v the_o canary_n lactantius_n be_v of_o opinion_n that_o the_o earth_n be_v a_o plain_a and_o not_o a_o round_a body_n and_o will_v not_o believe_v there_o be_v any_o such_o thing_n as_o antipode_n which_o be_v now_o receive_v and_o embrace_v for_o a_o certain_a approve_a truth_n since_o the_o earth_n globular_a form_n have_v be_v discover_v there_o have_v be_v many_o disagree_a opinion_n about_o a_o first_o meridian_n geographer_n begin_v at_o st._n michael_n at_o gratioso_fw-la at_o pico_n some_o begin_v at_o the_o lizard_n of_o england_n other_o at_o london_n some_o at_o paris_n a_o spanish_a merchant_n willing_a to_o prefer_v a_o island_n to_o this_o honour_n write_v viz._n nullum_fw-la inveni_fw-la inter_fw-la auctores_fw-la quos_fw-la legebam_fw-la concordiam_fw-la aliis_fw-la hesperides_n insulae_fw-la pro_fw-la primario_fw-la meridiano_fw-la placebant_fw-la quibusdam_fw-la corni_fw-la insula_fw-la pluribus_fw-la fortunatae_fw-la insulae_fw-la non_fw-la nullis_fw-la palma_n insula_fw-la aliis_fw-la alia_fw-la atque_fw-la alia_fw-la loca_fw-la etc._n etc._n and_o a_o little_a further_o propose_v a_o island_n he_o call_v abroxos_n it_o lie_v towards_o the_o coast_n of_o brasile_n ought_v he_o not_o think_v you_o to_o have_v be_v complain_v of_o to_o the_o pope_n for_o not_o know_v his_o duty_n to_o st._n peter_n church_n in_o rome_n the_o reason_n why_o many_o begin_v their_o first_o meridian_n from_o the_o isle_n azore_n be_v because_o it_o be_v say_v thereabouts_o the_o compass_n have_v no_o variation_n concern_v which_o i_o shall_v say_v more_o when_o i_o come_v to_o write_v of_o longitude_n by_o magnetic_a variation_n methinks_v they_o take_v up_o too_o much_o breadth_n for_o a_o first_o meridian_n for_o suppose_v i_o be_v to_o draw_v a_o large_a draught_n of_o the_o azore_n or_o of_o the_o city_n of_o london_n where_o must_v i_o place_v my_o first_o meridian_n a_o meridian-line_n in_o a_o sea-chart_n or_o map_n be_v no_o big_a than_o other_o line_n save_v only_o so_o as_o to_o distinguish_v it_o from_o the_o rest_n beside_o astronomer_n and_o astrologer_n pretend_v to_o observe_v and_o calculate_v to_o second_o of_o time_n and_o motion_n therefore_o our_o first_o meridian_n ought_v to_o be_v suppose_v to_o be_v a_o small_a narrow_a line_n or_o circle_n i_o can_v baffle_v and_o impose_v on_o the_o world_n as_o our_o predecessor_n have_v false_a argument_n for_o other_o place_n from_o whence_o they_o may_v account_v their_o first_o meridian_n god_n forbid_v i_o shall_v be_v so_o wicked_a honour_n and_o glory_n and_o beginning_n of_o good_a belong_v to_o god_n a_o first_o meridian_n may_v be_v represent_v and_o if_o the_o head_n of_o our_o church_n and_o state_n think_v it_o good_a let_v there_o be_v make_v a_o figure_n represent_v a_o first_o meridian_n and_o erect_v over_o st._n paul_n church_n in_o london_n with_o this_o inscription_n glory_n be_v to_o god_n good_a will_n towards_o man_n this_o present_v our_o first_o meridian_n etc._n etc._n this_o may_v be_v a_o ornament_n to_o our_o church_n may_v it_o be_v sacrilege_n for_o any_o of_o the_o king_n of_o england_n subject_n to_o account_v any_o other_o meridian_n a_o first_o merid._n save_o that_o which_o pass_v right_a over_o st._n pauls-church_n in_o london_n cut_v the_o equinoctial_a at_o right_a angle_n and_o pass_v through_o both_o its_o pole_n i_o hope_v this_o advice_n may_v put_v a_o period_n to_o cavil_v about_o a_o first_o meridian_n indeed_o i_o may_v except_v against_o wicked_a captious_a atheistical_a humour_n for_o there_o be_v never_o any_o thing_n by_o the_o wit_n of_o man_n so_o well_o devise_v or_o so_o sure_o establish_v which_o in_o continuance_n of_o time_n have_v not_o be_v corrupt_v it_o be_v always_o midday_n or_o noon_n in_o some_o part_n of_o the_o world_n every_o meridian_n be_v divide_v into_o four_o part_n or_o four_o time_n ninety_o degree_n and_o subdivide_v etc._n etc._n they_o be_v innumerable_a but_o you_o may_v reduce_v they_o to_o what_o number_n you_o please_v as_o to_o 21600_o or_o half_o so_o many_o or_o more_o or_o less_o as_o be_v most_o convenient_a for_o your_o purpose_n they_o be_v all_o equidistant_n at_o the_o equinoctial_a and_o in_o every_o lesser_a circle_n parallel_n to_o the_o equinoctial_a but_o incline_v near_o together_o until_o they_o intersect_v one_o another_o in_o the_o pole_n i_o allow_v but_o one_o first_o meridian_n begin_v at_o st._n pauls-church_n in_o london_n or_o if_o occasion_n require_v you_o may_v begin_v at_o any_o other_o part_n of_o the_o same_o meridian_n chap_n ii_o a_o definition_n of_o longitude_n circle_n of_o longitude_n on_o the_o earth_n have_v their_o beginning_n at_o any_o part_n of_o our_o first_o meridian_n pass_v round_o the_o earth_n and_o terminate_v where_o they_o begin_v may_v be_v imagine_v to_o be_v infinite_a in_o number_n but_o may_v be_v reduce_v to_o what_o number_n you_o think_v most_o convenient_a for_o your_o purpose_n there_o be_v but_o one_o great_a circle_n the_o equinoctial_a all_o circle_n parallel_v to_o it_o be_v lesser_a and_o lesser_a circle_n as_o they_o decline_v towards_o the_o pole_n each_o divide_v into_o 360°_n and_o subdivide_v etc._n etc._n and_o may_v be_v account_v either_o easterly_a or_o westerly_n as_o the_o practitioner_n please_v it_o be_v our_o design_n to_o measure_v the_o arch_n of_o these_o circle_n by_o astronomical_a observation_n or_o otherwise_o thereby_o to_o know_v our_o difference_n of_o longitude_n from_o our_o first_o meridian_n when_o we_o be_v either_o to_o the_o eastward_o or_o westward_o of_o the_o same_o longitude_n in_o the_o heaven_n be_v account_v on_o one_o great_a circle_n the_o ecliptic_a you_o may_v if_o you_o please_v also_o account_v it_o on_o lesser_a circle_n parallel_n to_o the_o ecliptic_a but_o that_o be_v needless_a and_o not_o usual_a which_o have_v its_o beginning_n at_o the_o first_o point_n of_o aries_n or_o where_o the_o
bear_v from_o we_o about_o north_n distant_a 6_o or_o 7_o league_n the_o mean_a variation_n by_o three_o azimuth_n compass_n and_o nine_o observation_n be_v 10°_n n._n westerly_n the_o same_o year_n november_n the_o 16_o variation_n at_o st._n helena_n 1°_n 4′_n n._n westerly_n the_o difference_n be_v 8°_n 56′_n the_o the_o meridian_n distance_n by_o plain_a chart_n be_v 20°_n difference_n of_o longitude_n be_v 21°_n 54′_n in_o sail_v direct_o between_o the_o two_o aforesaid_a place_n we_o raise_v or_o lay_v sea_n term_n the_o variation_n somewhat_o gradual_o therefore_o have_v the_o difference_n of_o longitude_n and_o the_o difference_n of_o the_o variation_n give_v between_o the_o two_o say_a place_n it_o may_v be_v suppose_v that_o the_o difference_n of_o longitude_n between_o the_o place_n may_v be_v find_v by_o observation_n of_o the_o variation_n i_o answer_v yes_o it_o may_v be_v near_o guess_v at_o and_o i_o know_v how_o to_o make_v proportion_n for_o find_v the_o difference_n of_o longitude_n by_o the_o variation_n not_o only_o between_o the_o two_o aforesaid_a place_n but_o in_o many_o other_o place_n but_o it_o be_v a_o method_n i_o do_v not_o approve_v of_o and_o advise_v the_o industrious_a seaman_n not_o to_o use_v it_o except_o in_o case_n of_o great_a necessity_n but_o rather_o to_o learn_v by_o former_a journal_o or_o from_o some_o experience_a artist_n what_o variation_n be_v at_o such_o place_n where_o you_o be_v bind_v to_o and_o all_o along_o your_o voyage_n as_o near_o as_o you_o can_v notwithstanding_o the_o variation_n of_o the_o variation_n i_o believe_v the_o difference_n of_o the_o variation_n between_o any_o two_o place_n in_o east-india_n may_v be_v always_o near_o the_o same_o and_o not_o only_o there_o but_o in_o most_o other_o part_n of_o the_o world_n near_o the_o isle_n azore_v except_v that_o be_v not_o above_o 20_o or_o 30_o degree_n distant_a asunder_o this_o i_o recommend_v as_o a_o secret_a worthy_a observation_n but_o there_o be_v several_a place_n that_o will_v not_o allow_v of_o any_o proportion_n like_o the_o former_a as_o the_o down_n the_o channel_n of_o england_n and_o several_a degree_n westerly_a from_o vshant_n there_o be_v but_o little_a difference_n in_o the_o variation_n the_o variation_n also_o alter_v apace_o in_o sail_v n._n or_o s._n under_o the_o same_o meridian_n not_o always_o gradual_o but_o in_o some_o place_n fast_o than_o in_o other_o it_o be_v find_v by_o experience_n and_o practice_n that_o the_o morning_n variation_n be_v the_o great_a as_o i_o have_v find_v sometime_o near_o 30_o minute_n and_o my_o opinion_n be_v that_o this_o difference_n happen_v not_o from_o the_o oval_a form_n or_o eliptical_a motion_n of_o the_o earth_n but_o that_o the_o sun_n refraction_n be_v considerable_o great_a in_o a_o morning_n if_o the_o sun_n great_a refraction_n be_v but_o 34′_n as_o our_o astronomer_n affirm_v how_o come_v it_o to_o pass_v that_o some_o englishman_n and_o hollander_n that_o winter_a in_o green-land_n and_o nova_n zembla_n see_v the_o sun_n five_o day_n soon_o then_o be_v expect_v according_a to_o the_o latitude_n of_o the_o place_n but_o to_o prevent_v the_o former_a difference_n or_o error_n subtract_v the_o sun_n refraction_n from_o the_o observe_v altitude_n allow_v the_o refraction_n when_o the_o sun_n be_v in_o the_o horizon_n to_o be_v a_o few_o minute_n more_o in_o a_o morning_n then_o in_o the_o evening_n i_o can_v at_o present_v certify_v you_o how_o many_o minute_n the_o difference_n be_v because_o i_o have_v lose_v my_o former_a amplitudal_n observation_n it_o be_v a_o fault_n in_o our_o east-india_n commander_n that_o they_o have_v not_o use_v to_o subtract_v the_o sun_n refraction_n etc._n etc._n they_o common_o take_v the_o sun_n declination_n from_o the_o precede_a noon_n which_o be_v also_o a_o great_a fault_n vide_fw-la astr_n ang._n page_n 94._o tabula_fw-la refractionum_fw-la triplex_fw-la but_o near_o the_o pole_n it_o be_v probable_a the_o sun_n refraction_n be_v great_a then_o near_o the_o equinoctial_a if_o the_o variation_n of_o the_o compass_n be_v better_o know_v and_o table_n of_o the_o variation_n for_o all_o the_o most_o note_a part_n in_o the_o world_n as_o headlands_n cape_n island_n etc._n etc._n the_o table_n calculate_v to_o a_o certain_a year_n because_o of_o the_o increase_n and_o decrease_v of_o the_o variation_n and_o the_o difference_n of_o the_o variation_n between_o those_o place_n then_o the_o knowledge_n thereof_o will_v be_v almost_o as_o good_a as_o the_o longitude_n know_v some_o few_o place_n except_v and_o if_o there_o be_v 10_o or_o 20_o year_n difference_n in_o lay_v or_o set_v down_o the_o variation_n in_o some_o place_n it_o matter_n not_o provide_v the_o year_n be_v set_v down_o when_o the_o variation_n be_v so_o much_o at_o such_o place_n and_o whether_o increase_v or_o decrease_v as_o for_o example_n suppose_v in_o the_o year_n 1708_o one_o shall_v happen_v to_o be_v 10_o or_o 12_o league_n south_n off_o of_o c._n b._n esperance_fw-fr and_o find_v the_o variation_n 12°_n 28′_n as_o i_o tell_v you_o before_o the_o difference_n of_o the_o variation_n between_o the_o say_a cape_n and_o st._n helena_n be_v 8°_n 56′_n by_o which_o rule_n when_o you_o be_v at_o the_o say_a cape_n you_o may_v know_v what_o the_o variation_n be_v at_o st._n helena_n viz._n 3°_n 32′_n both_o n._n westerly_n increase_v the_o like_a example_n may_v be_v consider_v of_o most_o other_o place_n in_o the_o world_n that_o be_v not_o above_o 20_o or_o 30°_n distant_a asunder_o except_o about_o the_o azore_n i_o present_v you_o with_o another_o method_n viz._n when_o we_o have_v such_o or_o such_o variation_n at_o london_n thereby_o to_o know_v what_o variation_n there_o be_v in_o any_o other_o part_n of_o the_o world_n for_o if_o at_o this_o present_a writing_n i_o know_v exact_o what_o variation_n there_o be_v in_o all_o part_n of_o the_o world_n i_o believe_v it_o will_v be_v no_o hard_a matter_n then_o by_o know_v the_o variation_n at_o london_n to_o find_v what_o variation_n there_o be_v in_o other_o part_n in_o future_a age_n this_o method_n i_o recommend_v to_o the_o consideration_n of_o the_o ingenious_a as_o also_o to_o see_v if_o they_o can_v find_v the_o lattitude_n and_o longitude_n of_o each_o magnetic_a pole_n but_o some_o people_n with_o think_v i_o have_v write_v nothing_o to_o the_o purpose_n if_o i_o do_v not_o tell_v they_o wherefore_o there_o be_v little_a or_o no_o variation_n about_o the_o azore_n the_o quantity_n of_o the_o earth_n attraction_n be_v but_o little_a in_o some_o place_n two_o degree_n or_o three_o may_v be_v the_o most_o and_o in_o most_o place_n at_o sea_n the_o more_o solid_a part_n of_o the_o earth_n have_v no_o attractive_a quality_n for_o then_o the_o needle_n be_v without_o the_o command_n of_o the_o more_o magnetic_a vigour_n of_o the_o earth_n as_o for_o example_n in_o the_o year_n 1688_o about_o 8_o or_o 10_o league_n at_o sea_n in_o the_o off_a at_o c._n b._n esperance_fw-fr when_o we_o have_v about_o ten_o deg._n variation_n i_o be_v tell_v by_o experience_a artist_n that_o there_o be_v not_o above_o 7½_n or_o 8_o deg._n at_o most_o variation_n ashore_o or_o in_o the_o harbour_n at_o the_o cape_n which_o be_v a_o very_a quick_a alteration_n for_o any_o where_o thereabouts_o above_o ten_o league_n off_o at_o sea_n in_o sail_v on_o any_o point_n of_o the_o compass_n 10_o league_n you_o will_v not_o alter_v your_o variation_n above_o 12_o or_o 14_o minute_n at_o most_o the_o like_a experiment_n have_v be_v prove_v on_o the_o coast_n of_o india_n and_o in_o the_o meriterranean_a therefore_o it_o be_v evident_a that_o promontory_n cape_n and_o headland_n draw_v the_o compass_n a_o little_a and_o that_o only_o when_o you_o be_v near_o they_o within_z 10_o or_o 12_o league_n beside_o the_o earth_n quality_n of_o hinder_v it_o from_o point_v to_o its_o pole_n there_o be_v four_o pole_n at_o least_o which_o have_v a_o sympathetical_a virtue_n with_o the_o magnetical_a needle_n to_o which_o it_o natural_o incline_v two_o of_o they_o that_o be_v further_a within_o the_o earth_n orb_n i_o call_v its_o more_o proper_a pole_n and_o the_o other_o two_o in_o the_o cortex_fw-la of_o the_o earth_n the_o magnetical_a pole_n these_o four_o pole_n draw_v the_o needle_n some_o one_o way_n and_o some_o another_o so_o that_o they_o hold_v it_o among_o they_o each_o require_v a_o share_n but_o that_o pole_n predominate_v most_o to_o which_o it_o be_v near_o the_o isle_n of_o azore_n i_o account_n lie_v almost_o between_o the_o two_o proper_a pole_n which_o two_o pole_n always_o for_o aught_o i_o know_v bear_v n._n and_o s._n from_o those_o island_n for_o there_o it_o be_v without_o the_o attraction_n of_o the_o magnetic_a pole_n but_o i_o believe_v there_o be_v some_o variation_n
they_o be_v careful_a in_o the_o practic_n part_n of_o navigation_n it_o very_o often_o happen_v that_o one_o error_n correct_v another_o as_o for_o example_n suppose_v we_o err_v 4_o or_o 5_o minute_n in_o the_o lattitude_n 2_o or_o 3_o minute_n in_o the_o sun_n r._n a._n or_o dec._n in_o the_o day_n time_n 3_o or_o 4_o min._n in_o the_o star_n r._n a._n and_o about_o as_o many_o in_o its_o altitude_n it_o be_v ten_o to_o one_o odds_o but_o these_o error_n if_o not_o much_o great_a will_v so_o help_v to_o correct_v one_o another_o that_o you_o will_v come_v very_o near_o the_o true_a time_n of_o the_o day_n or_o night_n and_o what_o blockhead_n will_v trust_v to_o one_o observation_n when_o he_o can_v have_v the_o mean_v of_o 6_o or_o 8_o observation_n i_o account_v he_o a_o ignorant_a observer_n that_o err_v above_o 10_o or_o 12_o second_n of_o time_n day_n or_o night_n trust_v not_o to_o mr._n seller_n colson_n norwood_n newton_n table_n of_o the_o sun_n r._n a._n for_o for_o they_o be_v of_o no_o use_n in_o this_o case_n in_o observe_v the_o time_n of_o the_o night_n be_v very_o careful_a to_o find_v the_o sun_n r._n a._n true_a for_o want_v of_o good_a table_n of_o the_o sun_n place_n and_o r._n asc_n table_n of_o the_o sun_n place_n and_o declination_n may_v serve_v with_o a_o little_a more_o trouble_n for_o example_n anno_fw-la 1696_o march_v the_o 19_o at_o 3_o h_o a.m._n 30°_n to_o the_o westward_n of_o our_o first_o meridian_n i_o desire_v to_o know_v the_o sun_n r._n asc_n the_o table_n of_o the_o sun_n place_n and_o dec._n in_o most_o book_n of_o navigation_n want_v correction_n mr._n parker_n ephemeris_fw-la for_o this_o year_n give_v the_o sun_n place_n at_o noon_n in_o our_o first_o meridian_n 9°_n 44′_n ♈_o ☉_o dec._n 3°_n 51′_n n._n but_o 30°_n to_o the_o westward_n the_o ☉_o place_n at_o noon_n will_v in_o 9°_n 49′_n ♈_o and_o the_o ☉_o dec._n 3°_n 53′_n n._n if_o you_o consider_v the_o diurnal_a difference_n of_o the_o ☉_o place_n and_o dec._n you_o will_v find_v his_o place_n at_o the_o time_n propose_v to_o be_v in_o 9°_n 27_o ♈_o ☉_o dec._n 3°_n 44′_n n._n then_o have_v the_o ☉_o present_z dec._n say_v as_o rad._n to_o tang._n comp._n 23°_n 29′_n ☉_o great_a declination_n so_o be_v the_o tang._n 3°_n 44′_n the_o present_a dec._n to_o the_o sine_fw-la 8°_n 38′_n the_o ☉_o r._n a._n from_fw-la ♈_o at_o the_o time_n and_o place_n propose_v but_o there_o be_v a_o ready_a way_n have_v find_v the_o ☉_o place_n vide_fw-la astr_n car._n tabula_fw-la ascensionum_fw-la rectarum_fw-la and_o against_o the_o ☉_o place_n be_v the_o ☉_o r._n ascention_n etc._n etc._n this_o example_n i_o think_v fit_a to_o add_v for_o seman_n instruction_n in_o answer_n to_o the_o second_o objection_n that_o the_o theory_n of_o the_o moon_n motion_n be_v false_a it_o be_v not_o long_o ago_o since_o mr._n thomas_n street_n live_v among_o we_o who_o say_v as_o i_o have_v be_v inform_v that_o he_o be_v capable_a to_o perfect_v the_o theory_n of_o the_o moon_n motion_n so_o that_o her_o place_n may_v be_v as_o true_o find_v by_o calculation_n as_o any_o of_o the_o rest_n of_o the_o planet_n if_o he_o have_v encouragement_n it_o be_v ten_o thousand_o pity_n he_o have_v not_o but_o such_o be_v our_o english_a ingratitude_n there_o be_v now_o live_v in_o england_n two_o man_n that_o i_o believe_v be_v capable_a to_o perfect_v the_o theory_n of_o the_o moon_n motion_n which_o if_o either_o of_o they_o will_v be_v please_v to_o undertake_v as_o also_o to_o furnish_v we_o with_o large_a map_n of_o the_o fix_a star_n such_o as_o dr._n sprat_n be_v please_v to_o mention_v hist_o r._n s._n p._n 190._o i_o may_v be_v capable_a to_o practise_v and_o instruct_v other_o in_o the_o practic_n part_n of_o longitude_n at_o sea_n or_o the_o ingenious_a may_v put_v it_o to_o practice_n without_o my_o further_a assistance_n table_n of_o the_o moon_n place_n right_a ascension_n and_o declination_n will_v be_v please_v easie_n and_o more_o intelligible_a to_o our_o seaman_n if_o they_o be_v true_o calculate_v for_o noon_n or_o midnight_n in_o our_o first_o meridian_n but_o i_o think_v i_o can_v find_v as_o great_a objection_n as_o either_o of_o the_o former_a it_o be_v very_o difficult_a to_o contrive_v a_o instrument_n useful_a at_o sea_n for_o take_v the_o moon_n true_a distance_n from_o fix_a star_n for_o if_o you_o err_v but_o one_o minute_n of_o motion_n in_o the_o distance_n it_o will_v produce_v a_o error_n of_o about_o 28′_n in_o longitude_n and_o if_o the_o star_n place_n which_o you_o take_v your_o distance_n from_o happen_v to_o be_v one_o or_o two_o minute_n false_a the_o error_n will_v be_v so_o much_o the_o great_a also_o idleness_n be_v the_o root_n of_o ignorance_n and_o many_o other_o evil_n our_o mathematic_a schoolmaster_n that_o teach_v navigation_n most_o of_o their_o scholar_n when_o they_o come_v to_o sea_n be_v half_a to_o begin_v again_o a_o seaman_n have_v much_o nightwork_n as_o well_o as_o daywork_n it_o be_v convenient_a to_o go_v to_o school_n at_o night_n to_o learn_v to_o know_v the_o star_n how_o to_o find_v the_o time_n of_o the_o night_n by_o observation_n and_o how_o to_o find_v the_o moon_n place_n by_o observation_n i_o mean_v to_o practise_v it_o for_o example_n be_v best_a precept_n many_o able_a mathematician_n have_v write_v concern_v find_v the_o longitude_n by_o the_o moon_n eclipse_n concern_v which_o you_o may_v find_v many_o example_n in_o ph._n trans_fw-la of_o the_o royal_a society_n as_o also_o in_o a_o new_a system_fw-la of_o the_o mathematics_n by_o sir_n ionas_n more_o in_o the_o doctrine_n of_o the_o sphere_n to_o which_o i_o refer_v you_o it_o be_v more_o difficult_a to_o find_v the_o longitude_n by_o a_o eclipse_n of_o the_o sun_n then_o of_o the_o moon_n because_o that_o of_o the_o moon_n happen_v at_o one_o and_o the_o same_o time_n all_o over_o the_o world_n but_o a_o eclipse_n of_o the_o sun_n appear_v various_a in_o the_o various_a part_n of_o the_o earth_n the_o duration_n of_o a_o solar_a eclipse_n appear_v long_a in_o some_o place_n of_o the_o earth_n then_o in_o other_o therefore_o the_o end_n of_o a_o solar_a eclipse_n happen_v not_o at_o the_o same_o moment_n of_o time_n all_o over_o the_o world_n the_o superior_a planet_n suffer_v no_o eclipse_n when_o the_o earth_n come_v between_o they_o and_o the_o sun_n because_o the_o conical_a shadow_n of_o the_o earth_n can_v reach_v they_o anno_fw-la 1688_o october_n the_o 14_o 12°_n 40′_n mer._n do_v west_n plain_a chart_n from_o the_o mauritius_n i_o observe_v the_o sun_n eclipse_v at_o the_o end_n of_o the_o eclipse_n the_o ☉_o alt_z 27°_n 35′_n ☉_o dec._n 12°_n 3′_n s._n lat._n 31°_n 6′_n s._n will_v give_v the_o hour_n of_o the_o day_n 10_o h_o 33′_n 48″_n a._n m._n in_o our_o first_o meridian_n the_o end_n of_o the_o eclipse_n happen_v by_o some_o calculation_n at_o 7_o h_o 15′_n a._n m._n the_o difference_n be_v 3_o h_z 18′_n 48″_n convert_v into_o degree_n and_o minute_n give_v 49°_n 41′_n longitude_n east_n from_o our_o first_o meridian_n the_o penumbra_fw-la of_o the_o moon_n disk_n signify_v little_a or_o nothing_o astronomer_n make_v more_o ado_n about_o it_o then_o needs_o brother_n tar_n have_v a_o care_n of_o peep_v on_o a_o eclipse_n of_o the_o sun_n through_o a_o telescope_n for_o endanger_v the_o eyesight_n as_o i_o know_v one_o captain_n norgrave_n do_v i_o will_v tell_v thou_o the_o best_a way_n i_o know_v for_o observe_v eclipse_n of_o sun_n or_o moon_n take_v a_o looking-glass_n set_v it_o before_o thou_o so_o that_o thou_o may_v see_v the_o sun_n or_o moon_n by_o reflection_n on_o the_o glass_n then_o with_o a_o perspective_n or_o two_o or_o three_o foot_n telescope_n look_v on_o the_o looking-glass_n for_o the_o sun_n etc._n etc._n or_o you_o may_v have_v smoke_v or_o red_a glass_n to_o save_v the_o eyesight_n that_o the_o longitude_n may_v be_v find_v by_o the_o moon_n eclipse_v any_o of_o the_o rest_n of_o the_o planet_n or_o any_o know_a fix_a star_n be_v as_o certain_a as_o by_o eclipse_n of_o the_o sun_n or_o moon_n if_o mr._n halley_n be_v capable_a to_o observe_v the_o transit_fw-la of_o the_o sun_n and_o mercury_n as_o appear_v by_o these_o word_n viz._n schema_fw-la solis_fw-la ad_fw-la ingressum_fw-la mercurii_n st._n helena_n anno_fw-la 1677_o octob._n 28_o 9_o h_o 26′_n 40″_n p._n m._n sure_o with_o ordinary_a telescope_n we_o may_v be_v capable_a to_o observe_v when_o a_o star_n begin_v to_o culminate_v and_o limerge_n in_o or_o near_o the_o moon_n disk_n of_o or_o concern_v longitude_n by_o the_o moon_n approach_v and_o apulse_n to_o fix_a star_n this_o some_o think_v will_v be_v the_o most_o