e manner in which mechanized astronomical models
developed in China, we can detect a similar line running from
Hellenistic time, through India and Islam to the medieval Europe that
inherited their learning. There are many differences, notably because of
the especial development of that peculiar characteristic of the West,
mathematical astronomy, conditioned by the almost accidental conflux of
Babylonian arithmetical methods with those of Greek geometry. However,
the lines are surprisingly similar, with the exception only of the
crucial invention of the escapement, a feature which seems to be
replaced by the influx of ideas connected with perpetual motion wheels.

HELLENISTIC PERIOD

Most interesting and frequently cited is the bronze planetarium said to
have been made by Archimedes and described in a tantalisingly
fragmentary fashion by Cicero and by later authors. Because of its
importance as a prototype, we give the most relevant passages in
full.[11]

Cicero's descriptions of Archimedes' planetarium are (italics supplied):

Gaius Sulpicius Gallus ... at a time when ... he happened
to be at the house of Marcus Marcellus, his colleague in
the consulship [166 B.C.], ordered the celestial globe to
be brought out which the grandfather of Marcellus had
carried off from Syracuse, when that very rich and
beautiful city was taken [212 B.C.].... Though I had heard
this globe (sphaerae) mentioned quite frequently on
account of the fame of Archimedes, when I saw it I did not
particularly admire it; for that other celestial globe,
also constructed by Archimedes, which the same Marcellus
placed in the temple of Virtue, is more beautiful as well
as more widely known among the people. But when Gallus
began to give a very learned explanation of the device, I
concluded that the famous Sicilian had been endowed with
greater genius than one would imagine possible for human
being to possess. For Gallus told us that the other kind
of celestial globe, which was solid and contained no
hollow space, was a very early invention, the first one of
that kind having been constructed by Thales of Miletus,
and later marked by Eudoxus of Cnidus--a disciple of
Plato, it was claimed--with constellations and stars which
are fixed in the sky. He also said that many years later
Aratus ... had described it in verse.... But this newer
kind of globe, he said, on which were delineated the
motions of