shown by the compass, for, by the compass, if a place A bear due east from a place B, the place B will bear due west from the place A; but this is not the case when measured with a quadrant of altitude.

88. The FIXED STARS are so called, because they have been usually observed to keep the same distance with respect to each other. The stars have an apparent motion from east to west, in circles parallel to the equinoctial, arising from the revolution of the earth on its axis, from west to east; and, on account of the precession of the equinoxes, their longitudes increase about 504 seconds in a year; this likewise causes a variation in their declinations and right ascensions: their latitudes are also subject to a small variation.

89. The POETICAL RISING AND SETTING OF THE STARS, so called because they are taken notice of by the ancient poets, who referred the rising and setting of the stars to the sun. Thus when a star rose with the sun, or set when the sun rose, it was said to rise and set Cosmically. When a star rose at sun-setting, or set with the sun, it was said to rise and set Achronically. When a star first became visible in the morning, after having been so near the sun as to be hid by the splendour of his rays, it was said to rise Heliacally; and when a star first became invisible in the evening, on account of its nearness to the sun, it was said to set Heliacally.

90. A CONSTELLATION is an assemblage of stars on the surface of the celestial globe, circumscribed by the outlines of some assumed figure, as a ram, a dragon, a bear, &c. This division of the stars into constellations is necessary, in order to direct a person to any part of the heavens where a particular star is situated.

The following Tables contain all the constellations on the New British Globes.

The zodiacal constellations are 12 in number, the northern constellations 34, and the southern 47, making in the whole 93.

Foreign mathematicians have changed the names of some of these constellations, diminished the number of stars in others, in order to form new constellations, &c. but as these modern improvements have not been introduced upon our globes, it will be unnecessary to specify them here.

The largest stars are called stars of the first magnitude; those of the sixth magnitude are the smallest that can be seen by the naked eye. The number of stars in each constellation, except those marked with asterisks, are taken from Flamstead.

An Alphabetical List of the Constellations with the Right Ascension (R.) and Declination (D.) of the middle of each, for the ready finding them on the Globe.

N. B. The figures in the left hand column refer to the numbers in the preceding tables, where the English names of the constellations are given, together with the number of stars in each, and the names of the principal stars: the letter N or S, immediately following the name of the constellation, shows whether it be north or south of the zodiac; if the constellation be situated in the zodiac it has the letter Z annexed to it. N and S in the column marked D, point out whether the middle of the constellation has north or south declination.