nomy, nay one of the greatest men that ever appeared on earth. Our Author is not the first who has spoken of Kepler with enthusiasm, though perhaps he goes too far, when he exalts him above Copernicus and Ticho-Brahe; who, he affirms, could have no advantage over the ancient founders of astronomy, of whose labours we have fome remains in the tables of the Perfians, Indians and Siamese; whereas Kepler destroyed the edifice of the ancients to erect another more permanent and more fublime. There is no doubt of Kepler's extraordinary genius, discoveries and merit: but if Copernicus had no advantage over the ancient founders of astronomy, what could induce our Author to call his labours the epocha of a grand revolution in aftronomy in the preceding volume, and to say in this, when he is introducing Kepler, that at the first appearance of the Copernican system, truth was new and without support, and stood in need of fuch a genius as Kepler to discern its grandeur? All this is not very confiftent. If in affirming that Copernicus had no advantage over the ancient astronomers, he has in view his ancient primitive nation, the faultless monster which the world ne'er faw, which had brought astronomy and the other sciences to perfection, and of whose science Copernicus and the rest had only recovered some fragments, he may, in this respect, say the fame thing of Kepler that he did of Copernicus;-and if he has not in view this primitive nation, but the astronomers whose names and labours have come down to us from an early antiquity, then it is not true that Copernicus, Ticho-Brahe, and others of that class had no advantage over the ancient founders of astronomy.

Be that as it may, Kepler was, indeed, a luminary of the first magnitude in the astronomical world, and there were even streaks of genius in his most extravagant fingularities. Descartes, Gregory, and even the immortal Newton acknowledge their obligations to him, on many occafions; and he will certainly be revered, as long as true genius and astronomical science remain in esteem among men. Kepler adopted, without hesitation, the Copernican system; but he went much farther: he discovered the true forms of the planetary orbits, proved that they were elliptical, and not circular; and it is this discovery, that, according to M. BAILLY, fet astronomy on a new and folid bafis, annihilated the system of the ancients, and went even beyond the science of the famous primitive people, who, by what we can learn (fays our Author) from the vesiges of antiquity, had got no farther than the knowledge of circular motions. Kepler's ge-nius and labours are admirably described and appreciated by our learned, ingenious and eloquent Author:-he shews us this great man in all his aspects, discovering the proportions of the ce lestial orbits, and those laws of their motions that laid the foundations

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dations of the Newtonian astronomy, creating a new science of optical astronomy, composed of the motion of the stars and the phenomenon of light by which it is perceived-perfecting, this application of optics to astronomy, the theory of eclipses, making discoveries which seemed to require the use of the telescope, before that inftrument was invented-associating natural philosophy to astronomy-applying the principles of metaphyfics to explain the phenomena of motion-with many other effential operations and improvements in astronomical science, which the curious Reader will certainly be desirous of perusing in the work itself.

M. BAILLY suspends his account of the labours of Kepler, in order to introduce his cotemporary and rival Galilei, who was born at Pisa, in 1564, who laid the foundations and unfolded the elementary truths, on which Newton created the fublime theory of motion, discovered the laws of accelerated motion in falling bodies, and enriched astronomical science with a multitude of other discoveries, which were greatly facilitated by his invention of the telescope, or at least by his application of it to astronomical uses. - It is one of those circumstances that would afflict humanity, if man's principal destination looked no farther than the present state of things, that Kepler lived and died in indigence, and that Galilei was perfecuted.

In the third book our Author treats, first, of the aftronomers that were the cotemporaries of Kepler and Galilei, and afterwards of their fuccessors. Here we meet with an account of the labours of Longomontanus, a Dane, Albert Curtius, Father Scheiner, a Jesuit (who was the first that attended to, or at leaft explained the elliptical form that the fun affumes in his approach to the horizon), de Rheita, Bayer of Augsburg, Robert Fiudd, and Horrox, the first who observed the passage of Venus, and seemed to have been born for that object alone. Horrox lived in the obscurity of retirement, and the filence of study, and at the age of twenty-two, when he died, he had already the foundest notions and the moit extensive knowledge of physical astronomy. Vendelinus, Sneillus, Blaeu, Hortenfius, Cavalieri, Fontana, the learned and indefatigable compiler Riccioli, Peyreic, and others of inferior note, are also treated in this book.

Book fourth. Decortes (fays M. BAILLY), who taught us to think, who broke the yoke of authority, and would admit no truths before they were examined with precision and ascertained by evidence, is one of those philofophers who produced the greatest number of errors. The parallel, or rather contraft, in which he represents the different methods followed by Bacon and Descartes in the investigation of truth, is beautiful, ingenious and folid, and though it contains, in substance, what has been often faid of these two great men, yet it has an aspect of noveity

novelty by that luminous arrangement of ideas, and that unequalled felicity of expreffion, that reign through this whole. work, and are particularly confpicuous in this fourth book. As to the merit of Descartes in astronomical science, it is confiderable; he opened a path to the most interesting discoveries by his geometrical inventions, and he discovered, in effect, that centrifugal force which is an agent of such importance in the motion of the celestial bodies; but he neither decompounded it, nor investigated the forces that conspire to produce it, nor difcerned the power ver that retains, counterbalances, and modifies it. His hypotheses in dioptrics and other branches of natural philosophy are admirably appreciated and criticised in the rest of this book; in which we find interesting digreffions from the main subject of the work before us.

The fifth book contains an account of Bouillaud, Hevelius, Huygens, and fome other astronomers, such as Ward, Street, Rook, Wing, Mercator, Linemann, and Langrenus. The celebrated Christian Huyghens appears here in all his luftre;-his improvements of the telescope, his discovery of Saturn's ring and of one of his fatellites; his pendulum, his writings, give him an eminent rank among astronomers.

The fixth book exhibits the erection of academies, and the invention of instruments; and in the seventh our Author treats of the methods of observing the heavenly bodies. This book is learned, full of matter, and incapable of being even superficially abridged. The principal object of the eighth book is the celebrated J. D. Caffini, who was born at Perinaldo in the county of Nice, in the year 1625, whose tables of the motions of the satellites, and other astronomical discoveries and improvements, procured him a high reputation, and an honourable fettlement in France, under the protection of Lewis XIV. and Colbert. In the ninth book M. Bailly treats of the measure of the earth, and of the voyages that have been undertaken in France for the improvement of astronomy; and in the tenth he enumerates the labours and discoveries of many eminent astronomers about the same time. The eleventh book contains the labours of Flamstead, Halley and Hook (which laid the foundations of aftronomy in England), and the discoveries that were made in that science from the year 1672 to 1686.

Newton, and Newton alone, employs the head, heart, imagination, and pen of our excellent Author in the twelfth book, which contains above one hundred and ten pages, and in which, not only, nothing is omitted, but all the rays, that were blended in the luftre of that immortal man, are diftinguished by M. BAILLY, and are collected here in all their glow of light and truth. There is a certain tone of eloquent fimplicity, gravity and dignity in this book, that is worthy of its fubject, and does fingular

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fingular honour to its Author. He praises Newton with pleas fure, knowledge, admiration and eafe. He considers all studied ornaments in his expreffions, as beneath the dignity of the English philofopher, who was fingularly modeft, did great things with fimplicity, and followed Nature. Newton, no doubt, is well known; but those who know him most will certainly peruse this part of M. BAILLY's work with the greatest pleasure; and what ample instruction, what a fund of admiration will it not yield to those who are not acquainted with all the wonders of this man's genius, and all the excellence and fimplicity of his heart?" I shall fay nothing of his studies (these are the words of our Author); he seems rather to have discovered, than studied, and it may be almost said, that he acquired knowledge by intuition. He ran through the elements of Euclid: the bare mention of the theorems laid open to him their demonftration, and he proceeded to the geometry of Descartes, where he difcerned the language of a great genius, and ideas proportioned to his own capacity and powers. No mistake, no errors have yet been discovered in his writings; accordingly, Fontenelle applies to him the witty thought of an ancient writer concerning the majestic river that fertilizes Egypt, and whose source was fo long unknown, il n'a pas été permis aux hommes de voir le Nil foible et naissant.”

After having remarked, that it was referved for Newton to demonftrate the causes of gravity, and to fecure that important difcovery upon the foundation of mathematical certainty, M. BAILLY enters into an ample detail concerning the system of attraction, and all the other discoveries of that transcendent genius. "His researches were admired-many, however, entertained doubts with respect to their results: time and long study were requifite in order to understand him, and to render even the most knowing worthy to receive his lessons." - We need not enter into our Author's enumeration of the fublime contents of the Newtonian philofophy; but we cannot resist the pleafure of making a few extracts from the portrait of the English philosopher, with which the Author concludes this twelfth book.

" Newton, says he, is as fingular by the character of his genius, as by his fublime discoveries; it was gold without alloy, perfectly pure. Genius, by its nature, is ardent, vehement, and the need in which it stands of motion, seems to be the spring which makes it foar. But the genius of Newton was vast without the ardor of paffion, and calm without lofing aught of its activity. The objects and ideas which other mortals pursue with fuch agitation, pain and effort, seem to have offered themselves to the intuition of this great man, who exhibits to us the image of an obferver, fixed and motionless, who fees fucceffively

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cessively the whole heavens unfolding, around him, their properties and powers. The genius of Newton seems to have transported him to the center of nature-to the point where all the rays of truth converge and terminate; there he became a simple spectator, and has related what he saw. What a distance is there between him and his great forerunners, both with respect to extent and accuracy of ideas! Their lustre was always more or less tarnished by errors--Newton produces nothing but truths."

"The fimplicity and modesty of Newton were the consequences of his fuperiority; men of that order execute with facility the most difficult things; how then should they admire what has cost them so little pain and effort? - Men applaud themselves most, when they are surprised at their productions, they set a high value on the fruits of painful efforts;-pride is the indication of mediocrity, and the acknowledgment of our weakness.".

"One of the circumstances that shew Newton's discoveries were (to him) as easy, as they were in themselves important and fublime, is the little pains he was at to insure to himself the honour of having made them. He suspended the publication of a curious discovery, because he saw that Mercator was also in the way to find it out, and if truth was investigated, it was equal to him who made the discovery. The first hints that were thrown out, questioning the originality of his ideas of light and colours, made him put off, for a great number of years, the publication of his Treatise on Optics, which is a work truly original and full of genius. The dispute, relative to the invention of the method of fluxions, gave him pain, not on account of his being obliged to share the honour of this invention with Leibnitz, but because his tranquillity was ruffled in the contest: Newton was defirous of that tranquillity, which is as necessary to the contemplation of nature as to the enjoyment of life. --Are those minds fit to be employed about the grand objects of nature and the universe, which are always accessible to the petty interefts of vain-glory, and the fumes of literary faction? Time glides along amidst these shameful divisions, genius pines, and truth escapes through the tumult. Newton defired tranquillity, because he knew what was the true employment of time; he was indifferent about fame, which followed him spontaneously, and remains infeparably attached to his memory: - If, as Plato thought, there is a fcale of beings which terminates in the highest degree of finite perfection, the nearest approach to Deity, the human species has many great men to present in this series; but Newton, accompanied with his pure, intellectual truths, would undoubtedly exhibit the highest degree of force and perfection to which the human mind has ever arisen, and would be sufficient,