awakened by the revolutionary doctrines of Copernicus. It may be
noted, as an interesting circumstance, that the time at which he
discovered the scheme of the solar system has coincided with a
remarkable epoch in the world's history. The great astronomer had
just reached manhood at the time when Columbus discovered the new
world.

Before the publication of the researches of Copernicus, the orthodox
scientific creed averred that the earth was stationary, and that the
apparent movements of the heavenly bodies were indeed real
movements. Ptolemy had laid down this doctrine 1,400 years before.
In his theory this huge error was associated with so much important
truth, and the whole presented such a coherent scheme for the
explanation of the heavenly movements, that the Ptolemaic theory was
not seriously questioned until the great work of Copernicus
appeared. No doubt others, before Copernicus, had from time to time
in some vague fashion surmised, with more or less plausibility, that
the sun, and not the earth, was the centre about which the system
really revolved. It is, however, one thing to state a scientific
fact; it is quite another thing to be in possession of the train of
reasoning, founded on observation or experiment, by which that fact
may be established. Pythagoras, it appears, had indeed told his
disciples that it was the sun, and not the earth, which was the
centre of movement, but it does not seem at all certain that
Pythagoras had any grounds which science could recognise for the
belief which is attributed to him. So far as information is
available to us, it would seem that Pythagoras associated his scheme
of things celestial with a number of preposterous notions in natural
philosophy. He may certainly have made a correct statement as to
which was the most important body in the solar system, but he