which, he has conquered that distant planet, and dragged him from the remotest depths of nature, and exposed him to the view of all." Galileo's glass was not of sufficient power to show him the real constitution of this extraordinary planet; it was reserved for Huyghens, about the year 1656, to declare to the world that these supposed attendant stars are, in fact, part of a ring which surrounds, and yet is completely distinct from the body of Saturn; and the still more accurate observations of Herschel have ascertained that it consists of two concentric rings revolving round the planet, and separated from each other by a space which our most powerful telescopes scarcely. enable us to measure.

Galileo's second statement concluded with the remark, that "in the other planets nothing new was to be observed;" but a month had scarcely elapsed, before he communicated to the world another enigma,

Hæc immatura a me jam frustra leguntur oy,

which, as he said, contained the announcement of a new phenomenon, in the highest degree important to the truth of the Copernican system. The interpretation of this is,

Cynthia figuras æmulatur mater amorum,

that is to say, Venus rivals the appearances of the moon -for Venus being now arrived at that part of her orbit in which she is placed between the earth and the sun,

*Huyghens announced his discovery in this form: a aa aa aa c c c c c deeeeeghi i ii i ii l l l l m m n n n n n n n n n o o o o p p q r r sttt ttu uu u u, which he afterwards recomposed into the sentence, Annulo cingitur, tenui, plano, nusquam cohærente, ad eclipticam inclinato. e Saturni Luna. Hagæ, 1656.

and consequently, with only a part of her enlightened surface turned towards the earth, the telescope shewed her in a crescent form, like the moon in a similar position, and tracing her through the whole of her orbit round the sun, or at least so long as she was not invisible from his overpowering light, Galileo had the satisfaction of seeing the enlightened portion in each position assume the form appropriate to that hypothesis. It was with reason, therefore, that he laid stress on the importance of this observation, which also established another doctrine scarcely less obnoxious to the Anti-Copernicans, namely, that a new point of resemblance was here found between the earth and one of the principal planets; and as the reflection from the earth upon the moon had shewn it to be luminous like the planets when subjected to the rays of the sun, so this change of apparent figure demonstrated that one of the planets, not near the earth, and therefore probably all, were in their own nature not luminous, and only reflected the sun's light which fell upon them; an inference, of which the probability was still farther increased a few years later by the observation of the transit of Mercury over the sun's disc.

It is curious that only twenty-five years before this discovery of the phases (or appearances) of Venus, a commentator of Aristotle, under the name of Lucillus Philalthæus, had advanced the doctrine that all the planets except the moon are luminous of themselves, and in proof of his assertion had urged, "that if the other planets and fixed stars received their light from the sun, they would, as they approached and receded from him, or as he approached and receded from them, assume the same

1

phases as the moon, which, he adds, we have never
yet observed."-He further remarks, "that Mercury
and Venus would, in the supposed case of their being
nearer the earth than the sun, eclipse it occasionally,
just as eclipses are occasioned by the moon." Perhaps
it is still more remarkable, that these very passages, in
which the reasoning is so correct, though the facts are
too hastily taken for granted, (the common error of that
school,) are quoted by Benedetti, expressly to show the
ignorance and presumption of the author. Copernicus,
whose want of instruments had prevented him from ob-
serving the horned appearance of Venus when between
the earth and sun, had perceived how formidable an ob-
stacle the non-appearance of this phenomenon presented
to his system; he endeavored, though unsatisfactorily,
to account for it by supposing that the rays of the sun
passed freely through the body of the planet, and Gali-
leo takes occasion to praise him for not being deterred
from adopting the system, which on the whole, appeared
to agree best with the phenomena, by meeting with some
which it did not enable him to explain. Milton, whose
poem is filled with allusions to Galileo and his astrono-
my, has not suffered this beautiful phenomenon to pass
unnoticed. After describing the creation of the Sun, he
adds:-

Hither, as to their fountain, other stars
Repairing, in their golden urns draw light,

And hence the morning planet gilds her horns.

Galileo also assured himself, at the same time, that the fixed stars did not receive their light from the sun. This he ascertained by comparing the vividness of their

light, in all positions, with the feebleness of that of the distant planets, and by observing the different degrees of brightness with which all the planets shown at different distances from the sun. The more remote planets did not, of course, afford equal facilities with Venus for so decisive an observation; but Galileo thought he observed, that when Mars was in quadratures, (or in the quarters, the middle points of his path on either side,) his figure varied slightly from a perfect circle. Galileo concludes the letter, in which he announces these last observations to his pupil Castelli, with the following expressions, showing how justly he estimated the opposition they encountered:-"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 stupid and 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 gaining the assent of the book-philosophers, let us abandon both the hope and the desire."

K 2

CHAPTER IX.

Account of the Academia Lincea-Del Cimento-Royal Society.

GALILEO's resignation of the mathematical professorship at Padua occasioned much dissatisfaction to all those who were connected with that university. Perhaps not fully appreciating his desire of returning to his native country, and the importance to him, and to the scientific world in general, of the complete leisure which Cosmo secured to him at Florence, (for by the terms of his diploma he was not even required to reside at Pisa, nor to give any lectures, except on extraordinary occasions, to sovereign princes and other strangers of distinction,) the Venetians remembered only that they had offered him an honorable asylum when almost driven from Pisa; that they had increased his salary to four times the sum which any previous professor had enjoyed; and, finally, by an almost unprecedented decree, that they had but just secured him in his post during the remainder of his life. Many took such offence as to refuse to have any further communication with him; and Sagredo, a constant friend of Galileo, wrote him word that he had been threatened with a similar desertion unless he should concur in the same peremptory resolution, which threats, however Sagredo, at the same time, intimates his intention of braving.

Early in the year 1611, Galileo made his first appearance in Rome, where he was received with marks of distinguished consideration, and where all ranks were