Astronomical Myths: Based on Flammarions's "History of the Heavens"

by J. F. Blake; Camille Flammarion

The Siamese only reckoned twenty-seven, and occasionally inserted an extra one, called Abigitten, or intercalary moon. They made use, moreover, of the constellations to tell the hour of the night by their position in the heavens, and their method of doing this appears to have involved their having twenty-eight constellations. The names of the twenty-eight divisions among the Arabs were derived from parts of the larger constellations that made the twelve signs, the first being the horns, and the second the belly, of the Ram.

The twenty-eight divisions among the Persians, of which we may notice that the second was formed by the Pleiades, and called Pervis, soon gave way to the twelve, the names of which, recorded in the works of Zoroaster, and therefore not less ancient than he, were not quite the same as those now used. They were the Lamb, the Bull, the Twins, the Crab, the Lion, the Ear of Corn, the Balance, the Scorpion, the Bow, the Sea-Goat, the Watering-pot, and the Fishes.

Nor were the Chinese continually bound to the number twenty-eight. They, too, had a zodiac for the sun as well as the moon, as may be seen on some very curious pieces of money, of which those figured below are specimens.

Fig. 10.

On some of these the various constellations of the Northern hemisphere are engraved, especially the Great Bear—under innumerable disguises—and on others the twelve signs of the zodiac. These are very different, however, from the Grecian set—they are the Mouse, the Bull, the Tiger, the Hare, the Dragon, the Serpent, the Horse, the Ram, the Monkey, the Cock, the Dog, and the Pig. The Japanese series were the same. The Mongolians had a series of zodiacal coins struck in the reign of Jehanjir Shah (1014). He had pieces of gold stamped, representing the sun in the constellation of the Lion; and some years afterwards other coins were made, with one side having the impress of the particular sign in which the sun happened to be when the coin was struck. In this way a series is preserved having all the twelve signs. Tavernier tells the story that one of the wives of the Sultan, wishing to immortalise herself, asked Jehanjir to be allowed to reign for four-and-twenty hours, and took the opportunity to have a large quantity of new gold and silver zodiacal coins struck and distributed among the people.

The twenty-eight divisions are less known now, simply from the fact that the Greeks did not adopt them; but they were much used by the early Asian peoples, who distinguished them, like the twelve, by a series of animals, and they are still used by the Arabs.

So far for the nature of the zodiac, as used in various countries, and as adopted from more ancient sources by the Greeks and handed on to us. It is very remarkable that the arrangement of it, and its relation to the pole of the equator, carries with it some indication of the age in which it must have been invented, as we now proceed to show.

We may remark, in the first place, that from very early times the centre of the zodiacal circle has been marked in the celestial sphere, though there is no remarkable star near the spot; and the centre of the equatorial circle, or pole, has been even less noticed, though much more obvious. We cannot perhaps conclude that the instability of the pole was known, but that the necessity for drawing the zodiac led to attention being paid to its centre. Both the Persians and the Chinese noted in addition four bright stars, which they said watched over the rest, Taschter over the east, Sateris over the west, Venaud over the south, and Hastorang over the north. Now we must understand these points to refer to the sun, the east being the spring equinox, the west the autumnal, and the north and south the summer and winter solstices. There are no stars of any brilliancy that we could now suppose referred to in these positions; but if we turn the zodiac through 60° we shall find Aldebaran, the Antares, Regulus, and Fomalhaut, four stars of the first magnitude, pretty nearly in the right places. Does the zodiac then turn in this way? The answer is, It does.

The effect of the attraction of the sun and moon upon the equatorial protuberance of the earth is to draw it round from west to east by a very slow motion, and make the ecliptic cross the equator each year about one minute of arc to the east of where it crossed it the year before. So, then, the sidereal year, or interval between the times at which the sun is in a certain position amongst the stars, is longer than the solar year, or interval between the times at which the sun crosses the equator at the vernal equinox. Now the sun's position in the zodiac refers to the former, his appearance at the equinox to the latter kind of year. Each solar year then—and these are the years we usually reckon by—the equinox is at a point fifty seconds of arc to the east on the zodiac, an effect which is known by the name of the precession of the equinoxes.