was revived, and when Copernicus supported his view that the earth
moves and is not fixed.

It may be easy to explain the association of the name of Copernicus
with the Keplerian system. But the time has long passed when the
historian can support in any way this popular error, which was started
not by astronomers acquainted with Kepler's work, but by those who
desired to put the Church in the wrong by extolling Copernicus.

Copernicus dreaded much the abuse he expected to receive from
philosophers for opposing the authority of Aristotle, who had declared
that the earth was fixed. So he sought and obtained the support of
the Church, dedicating his great work to Pope Paul III. in a lengthy
explanatory epistle. The Bishop of Cracow set up a memorial tablet in
his honour.

Copernicus was the most refined exponent, and almost the last
representative, of the Epicyclical School. As has been already
stated, his successor, Tycho Brahe, supported the same use of
epicycles and excentrics as Copernicus, though he held the earth to be
fixed. But Tycho Brahe was eminently a practical observer, and took
little part in theory; and his observations formed so essential a
portion of the system of Kepler that it is only fair to include his
name among these who laid the foundations of the solar system which we
accept to-day.

In now taking leave of the system of epicycles let it be remarked that
it has been held up to ridicule more than it deserves. On reading
Airy's account of epicycles, in the beautifully clear language of his
_Six Lectures on Astronomy_, the impression is made that the