observation was taken, the ship's position being by account lat. 6°4'S.: long. 115° 1′E. 13. Dec. 12th, 1854, the following double altitude of the sun was taken:— app. time at ship. 12d Oh 20m 12" 12 4 0 12 obs. alt. O 59° 24′ 9′′ bearing N. 21°E. 35 57 26 the course and distance in the interval, N. 33°W. 28 miles: eye, 19 feet required the true latitude when the second observation was made, the ship's position at the time being by account, lat. 52° 58'S.: long. 60° 3′E. 14. Feb. 19th. 1854, A.M. at ship: lat. 6° 4'S.: the following lunar observation was made: : obs. dist. mear limbs. 108° 5' 40" -35 eye, 25 feet: time by chronometer, 18d 13h 2m 50", which was supposed to be 17" 6s slow on mean time at Greenwich: determine the error of the chronometer on mean time at Greenwich by lunar: also the longitude. 15. Nov. 15th 1854: A.M. at ship: lat. 39° 50'N. the following observations were made: eye 16 feet: time by chronometer 15d 1h 0m 58, 59° 46′ 0′′ + 10 which was supposed to be 48m 11.5 slow on mean time at Greenwich: required the error of the chronometer on Greenwich mean time by lunar, and the longitude. 16. May 9th, 1854, at 8h 36m P.M. by watch at ship: lat. 8° 26' S long. by account, 107° 42'W. 17. Feb. 6th, 1854: at 5h 20m 46 P.M. by watch at ship: lat. 50° 13'N.: long. by account, 22°W.: 18. Feb. 12th. 1854: at 10h 2m 25 P.M. by watch at ship: lat. 4o 16'S: long. by ac. 131° 47′ E. obs. alt Saturn (centre) W. of mer. obs alt. < obs. dist. n.l.& h 19. Sept. 3rd, 1854: at 7h 40m 25 P.M. by watch at ship: lat. 46° 30'S: long. by account 90° 40′W. 20. A ship by dead reckoning has made S. 7° W. 100 miles, but by observation it is found to have made S. 50° E. 94 miles, required the set and drift of the current. 21. A ship by dead reckoning has made N. 69° E. 82 miles, but by observation it is found to have made S. 65° E. 101 miles, required the set and drift of the current. 22. A ship by dead reckoning has made E. 75 miles, but by observation it is found to have made N. 63° E. 78 miles, required the set and drift of the current. 23. A ship by dead reckoning has made N.30°W. 105 miles, but by observation it is found to have made N. 20° W. 101 miles, required the set and drift of the current. Paper I. 1. Jan. 7, 1854: P.M. at ship: lat. 40° 36'S.: eye 27 feet: time by chronometer 7d 6h 20m 23, which was supposed to be 20m 28 fast on mean time at Greenwich: required the longitude, and error of chronometer on Greenwich mean time, by lunar observation. 2. Feb. 17th 1854: A.M. at ship: approximate latitude, 39°: long. 166° 30′E.: observed meridian altitude 50° 10′ 40′′: CS. of observer: index error +1′2′′: eye 18 feet: required the true latitude. 3. March 20th, 1854: at 7h 17m P.M. mean time at ship: longitude 19° 56'W.: the observed altitude of Polaris off the meridian being 54° 50′ 40′′: index error +1'10": eye 23 feet required the latitude. 4. April 2nd, 1854: the following observations were made for latitude, by double altitudes, app. time at ship, 8h 16m 445A.M. 11 1. 44 A.M. obs. alt. O 31° 24′ 13′′ bearing E. by S. 1S. 61 0 20 eye 22 feet: course and distance in the interval S.E. 28 miles: lat. by account 30° 2′N.: long. 171° 11′E.: required the true latitude, when the second observation was made. 4a. Verify the above by Sumner's method. 5. April 15th, 1854: lat. 16° 50′N. long. 99° 52′W.: equal altitudes of the sun's lower limb being observed, when the corresponding times by chronometer were 15d 3h 50m 40s and 154 9h 20m 40°: determine the error of the chronometer for apparent and mean time at the place of observation, and also on mean time at Greenwich. 6. April 27th, 1854: the observed altitude of the sun's lower limb, in an artificial horizon, being 61° 15′ 40′′: index error, -2′ 10′′ required the true altitude of the sun's centre. 7. A ship by dead reckoning has made S.44°E. 97 miles, but by observation she is found to have made S. 11°W. 101 miles: determine the set and drift of the current. Paper II. 1. May 11th 1854: at 9h 48m 31 P.M. mean time by watch at ship: lat. 38° 40'S.: long. by ac. 171°6′E.: the observed distance of Regulus (a Leonis, and 's near limb being 65° 50′ 30′′: index error +1′ 16′′: required the true longitude. 2. May 10th, 1854, approximate latitude 55°: long. 86° 15′E. observed meridian altitude 40° 10′ 30′′: observer S. of : eye, 24 feet required the true latitude. 3. May 15th, 1854, at 111 Om 50 P.M. mean time at ship: long. 30° 40'W.: the observed altitude of Polaris off the meridian, being 49° 58′ 40′′: index error -50": eye 22 feet: required the latitude. 4. May 28th, 1854 the following observations were made for latitude by double altitudes, app. time at ship. 28d Oh 58m 30 28 3 29 42 obs. alt. O 66° 41′ 11′′ bearing N.W. eye 18 feet: the course and distance in the interval S.S.W.14 miles: lat. by ac. 3° 7′N.: long. 2° 15'W.: required the true latitude when the second observation was taken. 4a. Verify the above by Sumner's method. 5. May 16th, 1854: lat. 20° 28'S.: long. 28° 51'W.: equal altitudes of the sun's lower limb being observed, when the corresponding times, by chronometer were 15d 23h 5m 30s and 16d 4h 52m 10, required the error of the chronometer on apparent and mean time at the place of observation, and also on mean time at Greenwich. 6. May 24th, 1854: the observed meridian altitude of the sun's lower limb in an artificial horizon being 97° 43′ 50′′: index error +1′20′′ required the true altitude of the sun's centre. : 7. A ship by dead reckoning, makes N. by E. 106 miles, by observation she is found to have made N.N.W. 100 miles; determine the set and drift of the current. |