obvious conclusion that the stars might be bodies like our globe,
shining either by their own light or by that of the sun, would
have been a first step to the understanding of the true system of
the world.

There is historic evidence that this deduction did not wholly
escape the Greek thinkers. It is true that the critical student
will assign little weight to the current belief that the vague
theory of Pythagoras--that fire was at the centre of all things--
implies a conception of the heliocentric theory of the solar
system. But the testimony of Archimedes, confused though it is in
form, leaves no serious doubt that Aristarchus of Samos not only
propounded the view that the earth revolves both on its own axis
and around the sun, but that he correctly removed the great
stumbling-block in the way of this theory by adding that the
distance of the fixed stars was infinitely greater than the
dimensions of the earth's orbit. Even the world of philosophy was
not yet ready for this conception, and, so far from seeing the
reasonableness of the explanation, we find Ptolemy arguing against
the rotation of the earth on grounds which careful observations of
the phenomena around him would have shown to be ill-founded.

Physical science, if we can apply that term to an uncoordinated
body of facts, was successfully cultivated from the earliest
times. Something must have been known of the properties of metals,
and the art of extracting them from their ores must have been
practised, from the time that coins and medals were first stamped.
The properties of the most common compounds were discovered by
alchemists in their vain search for the philosopher's stone, but
no actual progress worthy of the name rewarded the practitioners