Part 98

Hist. of America, vol. i, b. i.

Footnote A24:

Galileo Galilei was a strenuous defender of the system of Copernicus; for which he was condemned by the inquisition, in the year 1635, under Pope Urban VIII. This extraordinary man was a native of Florence, and born in 1564. He died in 1642, aged seventy-eight years.

W. B.

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Amongst the fixed stars too, Galileo pursued his enquiries. The Milky-Way, which had so greatly puzzled the ancient Philosophers, and which Aristotle imagined to be vapours risen to an extraordinary height, he found to consist of an innumerable multitude of small stars; whose light appears indistinct and confounded together to the naked eye. And in every part of the heavens, his telescope shewed him abundance of stars, not visible without it. In short, with such unabated ardour did this great man range through the fields of Astronomy, that he seemed to leave nothing for others to glean after him.

Nevertheless, by prodigiously encreasing the magnifying powers of their telescopes, his followers made several great discoveries; some of which I shall briefly mention. Mercury was found to become bisected, and horned near its inferior conjunction, as well as Venus. Spots were discovered in Mars, and from their apparent motion, the time of his revolution on an axis nearly perpendicular to its orbit, was determined. A sort of belts or girdles, of a variable or fluctuating nature, were found to surround Jupiter, and likewise certain spots on his surface, whence he was concluded to make one revolution in about ten hours on his axis; which is likewise nearly perpendicular to his orbit. Five moons or satellites were found to attend Saturn, which Galileo’s telescope; on account of their prodigious distance, could not reach: And the form of his ring was found to be a thin circular plane, so situated as not to be far from parallel to the plane of our equator; and always remaining parallel to itself. This ring, as well as Saturn, evidently derives its light from the sun, as appears by the shadows they mutually cast on each other.

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Footnote A25:

It has been since ascertained that Saturn has seven satellites, as is more particularly mentioned in the subsequent note. W. B.

Footnote A26:

It was about six years after the delivery of this oration, (viz. on the 13th of March, 1781,) that Herschel discovered the Georgium Sidus. And nearly eight years and an half after this first discovery, he made two others: on the 28th of August, 1789, he was enabled to ascertain, by means of his telescope of forty feet focal length, that Saturn has a sixth satellite; and, on the 17th of September following, he found that he has a seventh. The same celebrated astronomer has since made several important discoveries. Thus, under the liberal patronage of his sovereign, has the great Herschel succeeded, by his extraordinary skill and industry in the making of very large specula, in constructing telescopes, which, in the words of the learned Mr. Vince, “have opened new views of the heavens, and penetrated into the depths of the universe; unfolding scenes which excite no less our wonder than our admiration.”

Many important discoveries (some of which are noticed in the foregoing pages of these memoirs) have been made by other eminent astronomers, since the date of Dr. Rittenhouse’s Oration; some of them, indeed, since his decease; among which are the discoveries of three new planets. W. B.

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Besides several other remarkable appearances, which Hugenius discovered amongst the fixed stars, there is one in Orion’s Sword, which, I will venture to say, whoever shall attentively view, with a good telescope and experienced eye, will not find his curiosity disappointed. “Seven small stars, (says he,) of which three are very close together, seemed to shine through a cloud, so that a space round them appeared much brighter than any other part of heaven, which being very serene and black looked here as if there was an opening, through which one had a prospect into a much brighter region.” Here some have supposed old night to be entirely dispossessed, and that perpetual daylight shines amongst numberless worlds without interruption.

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Footnote A27:

The celebrated Huygens, who, in his Latin works, is styled Hugenius. W. B.

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This is a short account of the discoveries made with the telescope. Well might Hugenius congratulate the age he lived in, on such a great acquisition of knowledge: And recollecting those great men, Copernicus, Regiomontanus, and Tycho, so lately excluded from it by death, what an immense treasure, says he, would they have given for it. Those ancient philosophers too, Pythagoras, Democritus, Anaxagoras, Philolaus, Plato, Hipparchus; would they not have travelled over all the countries of the world, for the sake of knowing such secrets of nature, and of enjoying such sights as these?

Thus have we seen the materials collected, which were to compose the magnificent edifice of astronomical Philosophy; collected, indeed, with infinite labour and industry, by a few volunteers in the service of human knowledge, and with an ardour not to be abated by the weaknesses of human nature, or the threatened loss of sight, one of the greatest of bodily misfortunes! It was now time for the great master-builder to appear, who was to rear up this whole splendid group of materials into due order and proportion. And it was, I make no doubt, by a particular appointment of Providence, that at this time the immortal Newton appeared. Much had been done preparatory to this great work by others, without which if he had succeeded, we should have been ready to pronounce him something more than human. The doctrine of atoms had been taught by some of the ancients. Kepler had suspected that the planets gravitated towards each other, particularly the earth and moon; and that their motion prevented their falling together: and Galileo first of all applied geometrical reasoning to the motion of projectiles. But the solid spheres of the ancients, or the vortices of Des Cartes, were still found necessary to explain the planetary motions; or if Kepler had discarded them, it was only to substitute something else in their stead, by no means sufficient to account for those grand movements of nature. It was Newton alone that extended the simple principle of gravity, under certain just regulations, and the laws of motion, whether rectilinear or circular, which constantly take place on the surface of this globe, throughout every part of the solar system; and from thence, by the assistance of a sublime geometry, deduced the planetary motions, with the strictest conformity to nature and observation.

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Footnote A28:

Among the many eminent astronomers in the sixteenth and seventeenth centuries, mentioned by Mr. Lalande, in his Astronomie, with interesting particulars concerning most of them, the only notice he there takes of his ingenious countryman, who endeavoured to establish the theory of Vortices which he had projected, is in these words: “Descartes (René,) né en Touraine en 1596, mort à Stockholm en 1650. Sa vie a été écrite fort au long par Baillet, à Paris, 1691, in 4^o.” W. B.

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Other systems of Philosophy have been spun out of the fertile brain of some great genius or other; and for want of a foundation in nature, have had their rise and fall, succeeding each other by turns. But this will be durable as science, and can never sink into neglect, until “universal darkness buries all.”

Other systems of Philosophy have ever found it necessary to conceal their weakness, and inconsistency, under the veil of unintelligible terms and phrases, to which no two mortals perhaps ever affixed the same meaning: But the Philosophy of Newton disdains to make use of such subterfuges; it is not reduced to the necessity of using them, because it pretends not to be of nature’s privy council, or to have free access to her most inscrutable mysteries; but to attend carefully to her works, to discover the immediate causes of visible effects, to trace those causes to others more general and simple, advancing by slow and sure steps towards the great First Cause of all things.

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