Note 11 — PREFACE

The objection which has been urged against astrology, that the signs are continually moving from their positions, cannot invalidate this conclusion. That objection has, in fact, no real existence; for Ptolemy seems to have been aware of this motion of the signs, and has fully provided for it in the 25th Chapter of the 1st Book of the Tetrabiblos. From that chapter it is clear that the respective influences he ascribes to the twelve signs (or divisions of the zodiac) were considered by him as appurtenant to the places they occupied, and not to the stars of which they were composed. He has expressly and repeatedly declared that the point of the vernal equinox is ever the beginning of the zodiac, and that the 30 degrees following it ever retain the same virtue as that which he has in this work attributed to Aries, although the stars forming Aries may have quitted those degrees: the next 30 degrees are still be accounted as Taurus, and so of the rest. There is abundant proof throughout the Tetrabiblos, that Ptolemy considered the virtues of the constellations of the zodiac distinctly from those of the spaces they occupied.