Questions.-No. III.

1. Required the course and distance from A to B.

2. How many miles are there in 10° of longitude in the latitude of Portsmouth?

3. A ship bore from me S.S.W.

W., and a current ran

in the intermediate space S.S.E. E., 72 miles an hour; how must I steer a boat to fetch the ship, supposing I can pull in still water 10 miles an hour?

4. March 4, 1837, at noon, a point of land in lat. 50° 48′ N., and long. 1° 6' W., bore by compass N.N.E. E., distant 15 miles, (variation 2 W.), afterwards sailed as by the following log account; required the latitude and longitude. in, on March 5, at noon.

5. At what time will the star a Lyræ pass the meridian of Portsmouth on May 11, 1837, and how far N. or S. of the zenith?

6. March 8, 1837, in long. 89° 48′ E., the observed. meridian altitude of the sun's lower limb was 51° 49′ 30′′, zenith north of the sun, the index correction was 3' 17", and the height of the eye above the sea 15 feet; required the latitude.

7. March 16, 1837, at 8h 2m P.M., mean time nearly, in long. 110° E., the observed meridian altitude of the moon's lower limb was 48° 47′ 36", zenith north of the moon, the index correction was 2' 47", and the height of the eye

above the sea was 13 feet; required the latitude.

8. July 7, 1837, the observed meridian altitude of the star a Cygni was 53° 29′ 38′′, zenith north of the star, the index correction was 5' 12", and the height of the eye above the sea was 16 feet; required the latitude.

9. Oct. 16, 1837, the observed meridian altitude of the star a Ursa Majoris under the North Pole was 5° 26′ 10′′, the index correction was - 2′ 10′′, and the height of the eye

above the sea was 17 feet; required the latitude.

10. Sept. 10, 1837, at 3h 42m A.M., mean time, in long. 83° 14′ E., the observed altitude of a Ursa Minoris was 39° 47′ 48′′, the index correction was + 3′ 45′′, and the height of the eye above the sea was 17 feet; required the latitude.

11. April 10, 1837, the following double altitude of the sun was observed.

Mean time nearly. 10h 14m A.M. 11 47 A.M.

Chronometer.
10h 9m 40s
11 43 28

Obs. alt. sun's L. L.
41° 15′ 45′′
46 43 12

True bearing.

S. E.
S. by E.

The run of the ship in the interval was N.W. 6 miles, the index correction was 4′ 24′′, and the height of the eye above the sea was 20 feet; required the true latitude at the second observation, the latitude by account being 51° N., and the longitude 1° 6′ W.

12. May 10, 1837, at 3h 10m P.M., mean time, in lat. 48° 12′ N., and long. by account 45° 10′ E., when a chronometer showed Oh 10m 42s, the observed altitude of the sun's lower limb was 37° 20′ 10′′, the index correction was + 3' 10", and the height of the eye above the sea was 18 feet; required the true longitude.

On May 1, 1837, at Greenwich mean moon, the chronometer was fast on Greenwich mean time 9m 50s, and its daily rate was 35.2 gaining.

13. January 16, 1837, at 3h 4m P.M., mean time nearly, in lat. 50° 50′ N., and long. by account 65° E., the following lunar observation was taken.

The height of the eye above the sea was 16 feet: required

the true longitude.

14. May 18, 1837, at 4h 50m A.M., mean time nearly, in lat. 18° 45′ S., and long. 99° 18′ E., the sun rose by compass S. 80° 12′ E.; required the variation.

15. March 7, 1837, at 9h 10m A.M., mean time nearly, in lat. 51° 10′ N., and long. 89° 12′ E., the compass bearing of the sun was S. 74° 50' E., and at the same time the observed altitude of the sun's lower limb was 21° 40′ 43", the index correction was 2′ 18′′, and the height of the eye above the sea was 14 feet; required the variation.

16. Required the time of high water at A. on March 10, 1837, A.M. and P.M.

Change tide at A. 6h 45m P.M. app. time.

Long. A. 98° E.

Elements from Nautical Almanac and Answers.

1. S. 17° 23′ E., 319'4.

2. 379''2.

3. W. b. S. S.

4. Corrected courses S. W. 15', or W.S. W. ≥ W.; departure course W. b. N. N. 11'9; E.S.E. E. 12.9; S. W. 25'4; N. 20'-2; W. S. 14'-7; N. b. W. W. 30'. N.b. E. E. 21'. Latitude in 51° 14' 54" N. Longitude in 1° 35' 24" W.

5. At 15h 12m 42s 12° 10' 11" S. of zenith.

6. Sun's declination on March 7, at Greenwich mean noon, 5° 14′ 8′′ S.; on March 8, 4° 50′ 46′′ S.; semidiameter 16' 7". Latitude 33° 5′ 44′′ N.

7. Moon's declination on March 16, at 0h, 26° 48′ 39′′ N.; at 1h, 26° 44′ 20" N. moon's horizontal semidiameter on March 16, at Greenwich mean noon 14' 45"1; on March 16, at Greenwich mean midnight 14' 44"9; corrected horizontal parallax 54' 8"-1 and 54' 7" 4. Latitude 67° 14′ 35′′ N.

8. Declination a Cygni 44° 41′ 59′′ N. Lat. 81° 22′ 12′′ N. 9. Declination of a Ursa Majoris 62° 37' 28" N. Latitude 32° 33' 1" N.

10. Right ascension mean sun, on Sept. 9, at Greenwich mean noon, 11h 13m 18s 15. Latitude 38° 24' N.

11. Sun's declination on April 9, at Greenwich mean noon 7° 36′ 29′′ N., on April 10, 7° 58′ 43′′ N. Semidiameter 15' 58". Arc (1) 23° 13′ 15", Arc (2) 88° 17' 30", Arc (3) 65° 27' 0". Latitude 51° 0′ 47′′ N.

12. Sun's declination on May 10, at Greenwich mean noon 17° 38' 34"; on May 11, 17° 54′ 7′′ N., correct equation of time 3m 50s-2 S., and 3m 52.5 E.; semidiameter 15′ 51′′. Hour angle 3h 31m 21s. Longitude 51° 47' E.

13. Sun's declination on January 15, at Greenwich mean noon, 21° 6′ 42′′ S., on January 16, 20° 55′ 23′′ S., correct equation of time 9m 49s-1 A and 10m 95.8 A.; moon's horizontal semidiameter on January 15, at Greenwich mean midnight 15′ 2′′-1, on January 16, at Greenwich mean noon, 14′ 58′′0; corresponding horizontal parallax 55' 10"-6 and 54′ 55′′-3. True distance 121° 20 29"; distance at XXI., 120° 32′ 5′′, at XXIV., 121° 55′ 25′′. Hour angle 2h 54m 7s. Longitude 64° 55′ 45′′ E.

14. Sun's declination on May 17, at Greenwich mean noon, 10° 20′ 53′′ N., on May 18, 19° 34′ 14′′ N., true bearing E. 20° 34′ 45′′ N. Variation 30° 22′ 45′′ W.

15. Sun's declination on March 6; at Greenwich mean noon, 5° 37′ 27′′ S., on March 7, 5° 14′ 8′′ S., semidiameter 16' 8", true bearing N. 131° 9′ 15′′ E., variation 25° 59' 15" E.

16. Moon's Greenwich meridian passage on March 10, 3h 13m mean time on March 9, 2h 26m; moon's semidiameter 15′ 37′′, equation of time 11m S. from mean time, high water 9h 1m P.M. and 8h 37m A.M.

NOTE. The right ascension of mean sun is found in the Nautical Almanac in page II. of each month under the heading of "Sidereal Time."

Questions.-No. IV.

1. Required the course and distance from A to B.

Lat. A . . 60° 25' S.

B .. 64 12 S.

Long. A. 35° 22′ E.
B.. 30 10 E.

2. Sailed from Ushant due west 492.5 miles; required the latitude and longitude in.

3. A ship bore from me N.E. E. and a current set in the intermediate space N. W., 5 miles an hour; how must I steer a boat to fetch the ship, supposing I can pull in still water 7 miles an hour?

4. May 1, 1835, at noon, a point of land in latitude 51° 10' S., and long. 3° 15' E., bore by compass S.S.WW. distant 25 miles, variation 2 E., afterwards sailed as by the following log account; required the latitude and longitude in.