e most illustrious
of his age, forced by the threat of death to deny facts which his judges
as well as himself knew to be true! He was then committed to prison,
treated with remorseless severity during the remaining ten years of
his life, and was denied burial in consecrated ground. Must not that
be false which requires for its support so much imposture, so much
barbarity? The opinions thus defended by the Inquisition are now objects
of derision to the whole civilized world.

One of the greatest of modern mathematicians, referring to this subject,
says that the point here contested was one which is for mankind of the
highest interest, because of the rank it assigns to the globe that we
inhabit. If the earth be immovable in the midst of the universe, man has
a right to regard himself as the principal object of the care of Nature.
But if the earth be only one of the planets revolving round the sun, an
insignificant body in the solar system, she will disappear entirely
in the immensity of the heavens, in which this system, vast as it may
appear to us, is nothing but an insensible point.

The triumphant establishment of the Copernican doctrine dates from the
invention of the telescope. Soon there was not to be found in all Europe
an astronomer who had not accepted the heliocentric theory with its
essential postulate, the double motion of the earth--movement of
rotation on her axis, and a movement of revolution round the sun.
If additional proof of the latter were needed, it was furnished by
Bradley's great discovery of the aberration of the fixed stars, an
aberration depending partly on the progressive motion of light, and
partly on the revolution of the earth. Bradley's discovery ranked
in importance with that of the precession of the equinoxes. Roemer's
discovery of the progressive motion of light, though denounced by
Fontenelle as a seductive error, and not admitted by Cassini, at length
forced its way to universal acceptance.

Next it was necessary to obtain correct ideas of the dimensions of the
solar system, or, putting the problem under a more limited form, to
determine the distance of the earth from the sun.

In the time of Copernicus it was supposed that the sun's distance could
not exceed five million miles, and indeed there were many who thought
that estimate very extravagant. From a review of the observations of
Tycho Brahe, Kepler, however, concluded that the error was actually in
the opposite direction,