rch of Santa Croce, in
Florence. It was reserved for the nineteenth century to erect a suitable
memorial in his honour.

[Sidenote: Steady advance of the Copernican system.] The result of the
discoveries of Copernicus and Galileo was thus to bring the earth to her
real position of subordination and to give sublimer views of the
universe. Moestlin expresses correctly the state of the case when he
says, "What is the earth and the ambient air with respect to the
immensity of space? It is a point, a punctule, or something, if there be
any thing, less." It had been brought down to the condition of one of
the members of a family--the solar system. And since it could be no
longer regarded as holding all other bodies in submissive attendance
upon it, dominating over their movements, there was reason to suppose
that it would be found to maintain interconnexions with them in the
attitude of an equal or subordinate; in other words, that general
relations would be discovered expressive of the manner in which all the
planetary members of the solar system sustain their movements round the
sun.

[Sidenote: Kepler, his mode of inquiry.] Among those whose minds were
thoroughly occupied with this idea, Kepler stands pre-eminently
conspicuous. It is not at all surprising, considering the tone of
thought of those times, that he regarded his subject with a certain
mysticism. They who condemn his manner of thus viewing things do not
duly appreciate the mental condition of the generation in which he
lived. Whatever may be said on that point, no one can deny him a
marvellous patience, and almost superhuman painstaking disposition.
Guess after guess, hypothesis after hypothesis, he submitted to
computations of infinite labour, and doubtless he speaks the melancholy
truth when he says, "I considered and reflected till I was almost mad."
Yet, in the midst of repeated disappointment, he held, with a truly
philosophical determination, firmly to the belief that there must be
some physical interconnexion among the parts of the solar system, and
that it would certainly be displayed by the discovery of laws presiding
over the distances, times, and velocities of the planets. In these
speculations he was immersed before the publications of Galileo. In his
"Mysterium Cosmographicum" he says, "In the year 1595 I was brooding
with the whole energy of my mind on the subject of the Copernican
system."

[Sidenote: Discovery of Kepler's laws.] In 1609 he pu