de.

We left Galileo standing at his telescope and beginning his survey of
the heavens. We followed him indeed through a few of his first great
discoveries--the discovery of the mountains and other variety of
surface in the moon, of the nebulae and a multitude of faint stars, and
lastly of the four satellites of Jupiter.

This latter discovery made an immense sensation, and contributed its
share to his removal from Padua, which quickly followed it. Before the
end of the year 1610 Galileo had made another discovery--this time on
Saturn. But to guard against the host of plagiarists and impostors he
published it in the form of an anagram, which, at the request of the
Emperor Rudolph--a request probably inspired by Kepler--he interpreted;
it ran thus: The farthest planet is triple.

Very soon after he found that Venus was changing from a full-moon to a
half-moon appearance. He announced this also by an anagram, and waited
till it should become a crescent, which it did. This was a dreadful blow
to the anti-Copernicans, for it removed the last lingering difficulty to
the reception of the Copernican doctrine. Copernicus had predicted,
indeed, a hundred years before, that, if ever our powers of sight were
sufficiently enhanced, Venus and Mercury would be seen to have phases
like the moon. And now Galileo with his telescope verifies the
prediction to the letter.

Here was a triumph for the grand old monk, and a bitter morsel for his
opponents.

Castelli writes, "This must now convince the most obstinate." But
Galileo, with more experience, replies: "You almost make me laugh by
saying that these clear observations are sufficient to convince the most
obstinate; it seems you have yet to learn that long ago the observations
were enough to convince those who are capable of reasoning and those who
wish to learn the truth; but that to convince the obstinate and those
who care for nothing beyond the vain applause of the senseless vulgar,
not even the testimony of the stars would suffice, were they to descend
on earth to speak for themselves. Let us, then, endeavor to procure some
knowledge for ourselves, and rest contented with this sole satisfaction;
but of advancing in popular opinion, or of gaining the assent of the
book-philosophers, let us abandon both the hope and the desire."

What a year's work it had been! In twelve months observational astronomy
had made such a bound as it has never made before or since.[31] Why did
not