Sun's place to the eastern point of the horizon, will be the amplitude of the Sun at rising; bring the Sun's place to the western edge of the horizon, and the number of degrees to the west point, will be the amplitude of the Sun at setting.

EXAMPLES.

Find the Sun's amplitude, at the following places, on the days given:

1. London, 21st of June-Answer. 39° 48', North.

2. New York, 22d of December.

3. Philadelphia, 21st of May.

4. Cape of Good Hope, 10th of July.

5. Cape Town, 1st of April.

6. Washington, 18th of February.
7. Mexico, 23d of September.
8. Lima, 22d of December.

9. Quito, 21st of June.

PROBLEM XXII.

To find the Sun's altitude and azimuth, at any place, for any given day and hour.

RULE.-Rectify the globe for the latitude of the place, and screw the quadrant of altitude, over that latitude; find the Sun's place in the ecliptic, bring it to the meridian, and set the index to twelve; then, if the given time be before noon, turn the globe eastward; if afternoon, turn it westward, till the index points to the given hour; bring the graduated edge of the quadrant of altitude to coincide with the Sun's place; and the number of degrees, on the quadrant, from the Sun's place to the

horizon, will be the altitude; and the number of degrees on the horizon, from the north or south points of the meridian, to the graduated edge of the quadrant, will be the Sun's azimuth.

EXAMPLES.

Find the Sun's altitude and azimuth, at the following places, at the given time:

1. New York, May 10th, 9 o'clock, a. M.—Answer. Altitude, 45°; Azimuth, 1074 N., or 7210 S.

2. London, May 1st, 10 o'clock, A. M.-Answer. Altitude, 47°; Azimuth, 136° N., or 44° S.

3. Washington, June 21st, 8 o'clock, A. M.
4. Boston, December 5th, 3 o'clock, P. M.
5. Charleston, May 12th, 10 o'clock, a. M.
6. Madrid, January 20th, 4 o'clock, P. M.
7. Stockholm, July 1st, 6 o'clock, P. M.

CHAPTER III.

PROBLEMS FOR THE CELESTIAL GLOBE.

PROBLEM I.

To find the declination and right ascension of the Sun or a Star.

RULE.-Bring the Sun's place, or the star, to the graduated side of the brazen meridian, which is numbered from the equinoctial towards the poles; and the degree of the meridian, over the Sun's place, or the star, will be the declination; and the number of degrees on the equi

noctial, between the meridian and the first point of Aries, will be the right ascension.

EXAMPLES.

1. Find the Sun's declination, and right ascension, on

2. Find the declination and right ascension of―—

Aldebaran.—Answer. Dec., 16° 6′ N.; Right Ascension, 66°.

To find the latitude and longitude of a Star.

RULE. Screw the quadrant of altitude over the north or south pole of the ecliptic, according as the star is in north or south latitude; bring its graduated edge to the star: and the number of degrees, on the quadrant, from the ecliptic to the star, will be the latitude; and the number of degrees, on the ecliptic, from the first point of Aries, eastward to the quadrant, will be the longitude.

EXAMPLES.

1. Find the latitude and longitude of Aldebaran.—Answer. Latitude, 5° S.; longitude, 67°.

2. Required, the latitude and longitude of

PROBLEM III.

The declination and right ascension of a heavenly body being given, to find its place on the globe.

RULE. Bring the given degree of right ascension to that side of the brazen meridian, which is numbered, from the equinoctial towards the poles; then under the given degree of declination, on the meridian, will be the star or place required.

EXAMPLES.

1. What star has 991° of right ascension, and 161° of south declination?-Answer. Sirius.

2. What stars have the following right ascensions and declinations?

Right Ascension, 205° Declination, 5040 N.

3. When Venus has 311 of right ascension, and 12° of north declination, what is her place on the globe?

4. When Jupiter's right ascension is 212°, and its declination 20° south, what is its place on the globe?

5. When the right ascension of the moon is 350°, and its declination 12° south, what is its place on the globe?

PROBLEM IV.

The latitude and longitude of a heavenly body being given, to find its place on the globe.

RULE.-Elevate the north or south pole, according as the given declination is north or south, 661°; bring the pole of the ecliptic to the meridian, and screw the quad

rant of altitude over it; bring the graduated edge of the quadrant to the given degree of longitude, on the ecliptic; and, under the given degree of declination, on the quadrant, will be the star or place required.

EXAMPLES.

1. What star has 31° of north latitude, and 201° of longitude? -Answer. Arcturus.

2. What stars have the following latitudes and longitudes ?—

The latitude of a place, day of the month, and hour of the day, being given, to place the globe so as to represent the appearance of the heavens, at that place and time.

RULE.-Elevate the pole for the latitude of the place; find the Sun's place in the ecliptic, bring it to the meridian, and set the index to twelve; if the time be before. noon, turn the globe eastward; if afternoon, turn it westward, till the index points to the given hour; and the surface of the globe will then represent the appearance of the heavens for the given time and place.

EXAMPLES.

Represent the appearance of the heavens at New York, forOctober 12th, at 10 o'clock, P. M.

May 21st, at 9 o'clock, P. M.

December 22d, at 3 o'clock, A. M.