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the planets. M. BAILLY mentions his invention of the Epicycles, not only with indulgence, but even with commendation, fince at that early period it accounted for all the phenomena, and must be allowed to be ingenious, notwithstanding the contemptuous manner in which it has been rejected in modern
In the fecond book our Author treats of the inftruments invented by the first Alexandrian school, for the improvement of astronomical science.
Aftronomical obfervations were made with increafing degrees of accuracy, until the time of Hipparchus, whom our Author calls the patriarch of aftronomy, and whom Pliny denominated the confident of nature. This great man, whofe hiftory, genius, and improvements of the science now under confideration, form the fubject of the third book, flourished under Ptolomy Philometor a hundred and thirty years before Chrift, and treated aftronomy with a philofophical spirit unknown before his time. He confidered that fublime fcience under a general point of view, examined the received opinions, paffed in review the truths that had been discovered, and pointed out the method. of reducing them so far into a system, as to connect them with cach other. The Chaldean doctrine, which was an unphilofophical medley, made up of the refult of obfervation and the fuggeftions of credulity and fuperftition, was established in the Alexandrian fschool before he arofe: but he treated the determinations of the Chaldeans as Defcartes did the systems of the fcholaftics.Our Author enters into a long, circumftantial, and interefting detail of the labours and difcoveries of this celebrated aftronomer, who perceived the inequality of the fun, expreffed it in tables, invented the equation of time, the parallax, and the measure of distances; who undertook and executed a true description of the heavens, and laid the folid foundations of geographical and trigonometrical fcience. We cannot follow our learned Author in his ample account of these discoveries: the only thing that we can prefent to our Readers on this and all the other articles, is fuch a flight sketch of his narration as may indicate the entertainment and inftruction which they may expect in perufing this excellent hiftory.
Three hundred years paffed between Hipparchus and Ptolomy, who flourished at Alexandria, in the fecond century, under the empire of Adrian and Marcus Antoninus. This great man was the laft ornament of the Alexandrian school. He collected all the obfervations that had been made before his time, more efpecially thofe of Hipparchus and Poffidonius (the only fuccellor of Hipparchus who had any confiderable reputation), and was for a courfe of ages at the very fummit of aftronomical fame, till Copernicus removed him on a fudden from thence, M m 4
and took his place, which he is likely to keep as long as fun and moon fhall endure. Ptolomy collected the refult of his labours and aftronomical obfervations in an immortal work, intitled the Almagest, which was to furnish aftronomers of future times with the means of furpaffing their ancient guides. This work forms the communication between ancient and modern aftronomy, and contains methods, or the germs of methods (to ufe our Author's expreffion), which are ftill employed in our times. The account of this great aftronomer is the fubject of the fourth and fifth books of this hiftory.
In the fixth and seventh, M. BAILLY treats of the aftronomical knowledge of the Arabians, the modern Tartars, the Chinese, and even of fome of the American tribes or nations. As to the Arabians, he paints their fanatical paffion for conqueft, and the devaftations that accompanied it, in the moft ftriking. manner: he reprefents these booted difciples of Mahomet, rufhing into Egypt, making them felves mafters of Alexandria, deftroying that famous library, which was (if we may use that expreffion) the focus, where all the rays of science and learning, that proceeded from all parts of the globe, were united and collected:-he defcribes them heating their ftoves with the precious treasures contained in that immenfe collection; he reprefents fciences and letters as perifhing in the ruins of that library, and the Alexandrian fchool (which had been founded 280 years before the Chriftian æra) expiring in the middle of the seventh century. M. Bailly, indeed, turns the medal, and prefents the Arabians in an afpect that, at leaft, makes fome amends for their depredations: he tells us wittily, that barbarians are like chil dren, who deftroy whatever comes into their hands, and foon after regret what they have deftroyed, cry for it, and would be glad to have it back again. Thus, fays he, the Arabians, after having burned the library, and difperfed the philofophers of the Alexandrian Tchool, looked earnestly for the light, which they themselves had extinguifhed, and from the ashes, which their odious barbarity had accumulated, and were picking out eagerly, before the century ended, the precious remains of erudition and fcience that had escaped the flames. But though he allows them the honour of fome knowledge and fome difcoveries, fuch as that of the motion of the fun's apogee, the knowledge of the pendulum, and fome other ufeful obfervations; yet upon the whole he confiders them, as only commendable for having preferved the remains of the facred fire, which they had, at firft, attempted to extinguish, and reprefents them as more formed for judiciary aftrology than for aftronomical fcience.
In the eighth book M. BAILLY follows aftronomy into Europe. After having contemplated it in its imagined grandeur (imagined by him in his chimerical hypothefis of the Atlantis) in
the early ages, and amidst the changes and shocks it received, from the revolutions and convulfions of nations, as well as in the improvements and advantages it acquired from the protection of learned princes and the labours of men of genius, he confiders the noble edifice as indebted for the completion of its grandeur to Europe. Its grandeur, indeed, is not yet completed; but great things have been done, and are ftill doing for this purpose. Italy and Germany began the work: England and France have accelerated its conftruction; at this very moment all-nations feem to join hands to raise the building, and it is difficult to fay (we use our Author's words) where the fummit of its majestic grandeur will ftop. In this book M. BAILLY fhews the obligations which aftronomical science has, in this part of the globe, to the talents, genius, refearches and penetration of Purbach, Regiomontanus, and Waltherus. The firft of these three famous aftronomers compofed a theory of the planets, in which he en deavours to correct the fyftem of Ptolomy. John Muller (ge-` nerally known under the name of Regiomontanus, which is the Latin word for Koningsberg, the place of his nativity) was the difciple of Purbach, and furpaffed his mafter. He is confidered as the inventor of the Ephemerides, and in the year 1474, Pope Sixtus IV, having conceived a defign of reforming the calendar, fent for him, as the propereft perfon to execute that defign, and made him Archbishop of Ratifbon. Two years before this, in 1472, he observed a comet, which was the firft that was noticed in Europe. He was intimately perfuaded of the motion of the earth, and would perhaps have anticipated Copernicus in the reformation of aftronomy, and the re-invention of the true fyftem of the world, had he not been carried off by the plague, at the age of forty. Waltherus was the friend of Muller, who had affifted him by his liberal contributions to the expence that he was at in the conftruction of aftronomical inftruments, and obtained much inftruction from his converfation while he lived, and from his papers after his death. He was fufpected of having published fome of Muller's productions as his own; it cannot, however, be denied, that he was a man of fagacity and genius, of which his use of clocks, for the measure of time in aftronomical obfervations, is an evident proof.
The grand revolution that happened in the hiftory of aftronomy from the rife of Copernicus, towards the conclufion of the fifteenth century, to the time of Ticho-Brahe, who was born in the midft of the fixteenth, employs our Author in the ninth and tenth books of this hiftory, which conclude the firft volume. In fuch a fublime flight as that of Copernicus, who forbids us to believe. the motion that we fee, and engages us to confider as certain, that of which we have not the leaft perception or feeling; who represents the fun and the ftars as motionlefs, and our heavy
globe whirling itfelf with rapidity about the great fource of light, who could have imagined, that he had hit upon the truth, and found out the real fyftem of the univerfe? His difcovery became a fundamental truth in aftronomy, and he treated that fcience with the creating fpirit of a philofopher and a legiflator. He did not, however, bring the art of observing to perfection,—an art which requires rather patience and fagacity than invention and genius.
The science of aftronomy, notwithstanding this noble difcovery, flood in need of facts and obfervations; and these were furnished in a rich abundance by that fpirit of affiduity, curiofity, and detail, that diftinguifhed Ticho-Brahe, whom the impulfion of genius and nature rendered an aftronomer; while an eclipse of the fun in 1560 gave the word. The labours of Ticho-Brahe are well known: our Author unfolds, in an ample narration, their nature and their merit: he does juftice to this great man by acknowledging, that his fyftem is not incompatible with mathematical principles, and even that it corrects with dexterity the abfurdities that the hypothefis of Ptolomy had introduced into the wife arrangements of the univerfe. But he attacks the system of the Danish aftronomer upon the principles of natural philofophy, and that victoriously:-he blames him for not having adopted the fyftem of Copernicus, and for running the risk (by fubftituting another in its place) of plunging the truth anew in the very abyfs from which it fo lately emerged.
It is a mortifying inftance of the infirmity of human nature, even in its best appearances, that the greatest part of the eminent aftronomers already mentioned, were tainted with the superstitious nonsense of judicial aftrology. It was not only the Arabians who gave into this folly,-it was not only an Abu-elMaafar, who believed, amidst the nobleft efforts of learning and genius, that the Jewish, Egyptian, Turkish, and Christian religions were derived, respectively, from the conjunction of certain planets: but Hipparchus, Ptolomy, Purbach, Muller, Ticho-Brahe, and many others laboured under a fimilar folly; and this gives our Author occafion to fay feveral good things on this difeafe of the human imagination, in an excellent differtation on aftrology,
This volume is terminated by feveral inftructive illustrations relative to aftronomical science, a curious lift of the oriental aftronomical manufcripts, that are to be found in fome of the principal libraries of Europe, and an indication of the works of the principal aftronomers: the whole accompanied with thirteen plates accurately engraven.
Kepler feems to be the aftronomical hero of our Author. He was a native of Wirtemberg, and was born in 1571. According to M. BAILLY, Kepler was the true founder of modern aftro
nomy, nay one of the greateft 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 aftronomy, of whose labours we have fome remains in the tables of the Perfians, Indians and Siamefe; whereas Kepler deftroyed 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 aftronomy, what could induce our Author to call his labours the epocha of a grand revolution in afronomy in the preceding volume, and to say in this, when he is introducing Kepler, that at the first appearance of the Copernican fyftem, truth was new and without fupport, and flood in need of fuch a genius as Kepler to difcern its grandeur? All this is not very confiftent.—If in affirming that Copernicus had no advantage over the ancient aftronomers, he has in view his ancient primitive nation, the faultless monfter which the world ne'er faw,-which had brought aftronomy and the other sciences to perfection, and of whose science Copernicus and the rest had only recovered fome fragments, he may, in this refpect, say the same thing of Kepler that he did of Copernicus;-and if he has not in view this primitive nation, but the aftronomers whofe 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 clafs had no advantage over the ancient founders of aftronomy.
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 moft extravagant fingularities. Defcartes, 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 aftronomical fcience remain in efteem among men. Kepler adopted, without hesitation, the Copernican fyftem; but he went much farther: he difcovered the true forms of the planetary orbits, proved that they were elliptical, and not circular; and it is this difcovery, that, according to M. BAILLY, fet aftronomy on a new and folid bafis, annihilated the fyftem of the ancients, and went even beyond the fcience of the famous primitive people, who, by what we can learn (fays our Author) from the velges of antiquity, had got no farther than the knowledge of circular motions. Kepler's genius and labours are admirably defcribed and appreciated by our learned, ingenious and eloquent Author:he fhews us this great man in all his afpećts, discovering the proportions of the celeftial orbits, and thofe laws of their motions that laid the foun