onomy of
the Greeks."[139:1]

There is a widespread notion that early astronomy, whether amongst the
Hebrews or elsewhere, took the form of astrology; that the
fortune-telling came first, and the legitimate science grew out of it.
Indeed, a claim is not infrequently made that no small honour is due to
the early astrologers, since from their efforts, the most majestic of
all the sciences is said to have arisen.

These ideas are the exact contrary of the truth. Mathematical, or
perhaps as we might better call it, planetary astrology, as we have it
to-day, concerns itself with the apparent movements of the planets in
the sense that it uses them as its material; just as a child playing in
a library might use the books as building blocks, piling, it may be, a
book of sermons on a history, and a novel on a mathematical treatise.
Astrology does not contribute, has not contributed a single observation,
a single demonstration to astronomy. It owes to astronomy all that it
knows of mathematical processes and planetary positions. In astronomical
language, the calculation of a horoscope is simply the calculation of
the "azimuths" of the different planets, and of certain imaginary points
on the ecliptic for a given time. This is an astronomical process,
carried out according to certain simple formulae. The calculation of a
horoscope is therefore a straightforward business, but, as astrologers
all admit, its interpretation is where the skill is required, and no
real rules can be given for that.

Here is the explanation why the sun and moon are classed together with
such relatively insignificant bodies as the other five planets, and are
not even ranked as their chief. The ancient astrologer, like the modern,
cared nothing for the actual luminary in the heavens; all he cared for
was its written symbol on his tablets, and there Sun and Saturn could be
looked upon as equal, or Saturn as the greater. It is a rare thing for a
modern astrologer to introduce the place of an actual star into a
horoscope; the calculations all refer to the positions of the _Signs_
of the Zodiac, which are purely imaginary divisions of the heavens; not
to the _Constellations_ of the Zodiac, which are the actual star-groups.

Until astronomers had determined the apparent orbits of the planets, and
drawn up tables by which their apparent places could be predicted for
some time in advance, it was impossible for astrologers to cast
horoscopes of the present kind