es, or a whiff
of perfumery, he may or may not have borrowed his idea from the
slot-machine of Hero; but in any event, instead of being an innovator he
was really two thousand years behind the times, for the slot-machine of
Hero is the precise prototype of these modern ones.

The particular function which the mechanism of Hero was destined to
fulfil was the distribution of a jet of water, presumably used
for sacramental purposes, which was given out automatically when a
five-drachma coin was dropped into the slot at the top of the machine.
The internal mechanism of the machine was simple enough, consisting
merely of a lever operating a valve which was opened by the weight of
the coin dropping on the little shelf at the end of the lever, and which
closed again when the coin slid off the shelf. The illustration will
show how simple this mechanism was. Yet to the worshippers, who probably
had entered the temple through doors miraculously opened, and who now
witnessed this seemingly intelligent response of a machine, the result
must have seemed mystifying enough; and, indeed, for us also, when we
consider how relatively crude was the mechanical knowledge of the time,
this must seem nothing less than marvellous. As in imagination we walk
up to the sacred tank, drop our drachma in the slot, and hold our hand
for the spurt of holy-water, can we realize that this is the land of the
Pharaohs, not England or America; that the kingdom of the Ptolemies is
still at its height; that the republic of Rome is mistress of the world;
that all Europe north of the Alps is inhabited solely by barbarians;
that Cleopatra and Julius Caesar are yet unborn; that the Christian era
has not yet begun? Truly, it seems as if there could be no new thing
under the sun.

X. SCIENCE OF THE ROMAN PERIOD

We have seen that the third century B.C. was a time when Alexandrian
science was at its height, but that the second century produced also in
Hipparchus at least one investigator of the very first rank; though, to
be sure, Hipparchus can be called an Alexandrian only by courtesy.
In the ensuing generations the Greek capital at the mouth of the
Nile continued to hold its place as the centre of scientific and
philosophical thought. The kingdom of the Ptolemies still flourished
with at least the outward appearances of its old-time glory, and a
company of grammarians and commentators of no small merit could always
be found in the service of the famous