ound than that
afforded by the fact that, instead of claiming credit for his great
work, he deemed it rather necessary to apologize for it and, so far as
possible, to attribute his ideas to the ancients.

A century and a half after Copernicus followed the second great step,
that taken by Newton. This was nothing less than showing that the
seemingly complicated and inexplicable motions of the heavenly bodies
were only special cases of the same kind of motion, governed by the
same forces, that we see around us whenever a stone is thrown by the
hand or an apple falls to the ground. The actual motions of the heavens
and the laws which govern them being known, man had the key with which
he might commence to unlock the mysteries of the universe.

When Huyghens, in 1656, published his Systema Saturnium, where he first
set forth the mystery of the rings of Saturn, which, for nearly half a
century, had perplexed telescopic observers, he prefaced it with a
remark that many, even among the learned, might condemn his course in
devoting so much time and attention to matters far outside the earth,
when he might better be studying subjects of more concern to humanity.
Notwithstanding that the inventor of the pendulum clock was, perhaps,
the last astronomer against whom a neglect of things terrestrial could
be charged, he thought it necessary to enter into an elaborate defence
of his course in studying the heavens. Now, however, the more distant
objects are in space--I might almost add the more distant events are in
time--the more they excite the attention of the astronomer, if only he
can hope to acquire positive knowledge about them. Not, however,
because he is more interested in things distant than in things near,
but because thus he may more completely embrace in the scope of his
work the beginning and the end, the boundaries of all things, and thus,
indirectly, more fully comprehend all that they include. From his
stand-point,

"All are but parts of one stupendous whole,
Whose body Nature is and God the soul."

Others study Nature and her plans as we see them developed on the
surface of this little planet which we inhabit, the astronomer would
fain learn the plan on which the whole universe is constructed. The
magnificent conception of Copernicus is, for him, only an introduction
to the yet more magnificent conception of infinite space containing a
collection of bodies which we call the visible universe. How far does