Then Aratus proceeds to describe and explain all the Signs and Constellations as the Greeks in his day understood, or rather misunderstood, them, after their true meaning and testimony had been forgotten.
Moreover, Aratus describes them, not as they were seen in his day, but as they were seen some 4,000 years before. The stars were not seen from Tarsus as he describes them, and he must therefore have written from a then ancient Zodiac. For notwithstanding that we speak of “fixed stars,” there is a constant, though slow, change taking place amongst them. There is also another change taking place owing to the slow recession of the pole of the heavens (about 50" in the year); so that while Alpha in the constellation of Draco was the Polar Star when the Zodiac was first formed, the Polar Star is now Alpha in what is called Ursa Minor. This change alone carries us back at least 5,000 years. The same movement which has changed the relative position of these two stars has also caused the constellation of the Southern Cross to become invisible in northern latitudes. When the constellations were formed the Southern Cross was visible in N. latitude 40°, and was included in their number. But, though known by tradition, it had not been seen in that latitude for some twenty centuries, [pg 015] until the Cape of Good Hope had been discovered. Then was seen again The Southern Cross depicted by the Patriarchs. Here is another indisputable proof as to the antiquity of the formation of the Zodiac.
Ptolemy (150 a.d.) transmits them from Hïpparchus (130 b.c.) “as of unquestioned authority, unknown origin, and unsearchable antiquity.”
Sir William Drummond says that “the traditions of the Chaldean Astronomy seem the fragments of a mighty system fallen into ruins.”
The word Zodiac itself is from the Greek Ζωδιακός, which is not from Ζάω, to live, but from a primitive root through the Hebrew Sodi, which in Sanscrit means a way. Its etymology has no connection with living creatures, but denotes a way, or step, and is used of the way or path in which the sun appears to move amongst the stars in the course of the year.
To an observer on the earth the whole firmament, together with the sun, appears to revolve in a circle once in twenty-four hours. But the time occupied by the stars in going round, differs from the time occupied by the sun. This difference amounts to about one-twelfth part of the whole circle in each month, so that when the circle of the heavens is divided up into twelve parts, the sun appears to move each month through one of them. This path which the sun thus makes amongst the stars is called the Ecliptic.[18]
Each of these twelve parts (consisting each of about 30 degrees) is distinguished, not by numbers or by letters, but by pictures and names, and this, as we have seen, from the very earliest times. They are preserved to the present day in our almanacs, and we are taught their order in the familiar rhymes:—
“The Ram, the Bull, the heavenly Twins,
And next the Crab, the Lion shines,
The Virgin and the Scales;