Imágenes de páginas
PDF
EPUB

nor arguments fufficient to prove that the foul or animated molecule can have no feeling or perception without the affistance of the body. When therefore he maintains this, his third propofition against the Platonifts (who confidered the animal body as the prison of the foul, which reftrains its operations, retards its flight to perfection, and renders dim and dubious its view of truth, and who regarded the feparation as the moment that opened light and truth upon it in their purity), he has no means of defence but the fact above mentioned, and conjectures.

His conjectures are, indeed, ingenious, and if they do not administer either evidence, or a luminous probability with respect to what he defigns to prove, yet they unfold by the way interefting views of the operations of nature, and the fupreme wisdom by which they are directed. They are drawn from analogy, but are of too fubtile and intricate a nature not to lose what perfpicuity they have in an abridgment;—we there fore refer the metaphyfical reader to the memoir itself.

If the fuppofition of the animated molecule's lofing all its consciousness and fenfibility by its feparation from the animal body appears uncomfortable, our Academician revives our hopes of a new life, in his fourth propofition, which is, that the animated molecule, when feparated from the animal body, is not confounded and mingled with the general mass of matter, but follows the particular laws prescribed to the species to which it belongs. In the illuftration of this propofition, our Author obferves, among other things, that in the deftruction of bodies produced by natural causes, the decompofition is effected in such a manner, that the elementary parts of the diffolved body are separated from each other, and return each to the general mafs of the fubftances of its kind, in order to be employed anew in a manner conformable to their deftination. This fact we daily obferve in the decompofition of bodies compounded of air, water, and earth. When they are diffolved, either by fire or putrefaction, the particles of air, water, and earth, are reunited to their respective elements; and by this admirable operation of nature there are always materials for new productions.Now if fuch (fays our Author) is the courfe and procedure of nature in the deftruction of animal bodies, we may conclude by induction and analogy, that animated molecules are fubjected to a fimilar law, and that after the destruction of the bodies to which they were united, they repair to the general assemblage of their species, and remain there until the time comes which is fixed for their vivifying new bodies.-It was thus, probably, continues our Academician, that they found their way to an union with the animal bodies, now living;' it is this hypothefis alone (fays he) that can explain the union between foul and body:

for

for we muft either admit continual miracles, or suppose, that fouls unite themselves to animal bodies by natural means, by laws which refult from the specific qualities of the animal body and thofe of the animated molecule.-This is an ingenious dress given to the great ftoical revolution that renews nature at certain fixed periods. Be that as it may-the Author proves by the existence of monfters, which arife from accidental caufes, modifying the formation of natural productions, that the formation of animal bodies is produced by natural means under the empire of providence, and not by the immediate operations of the deity, which would have prevented the influence of these caufes. But the influence of thefe accidental caufes is much lefs frequent in the Animal than in the Mineral and Vegetable kingdoms; and this furnishes our Author with ä farther argument in favour of the prefervation of the animated molecule.

From thefe general confiderations in favour of his fourth propofition, M. SULZER thinks it neceffary to proceed to others more particular and more analogous to his subject. He is perfuaded that the primitive organized germs, from whence animals are produced, exift fince the commencement of the world, are diffufed throughout the globe, are preserved amidst the revolutions to which all things here below are expofed, and are developed, every one in its feason, according to regular and permanent laws.

As this fact is analogous to what our Academician has maintained concerning animated molecules, he proposes in a following memoir to exhibit the reasons which have induced him to adopt the hypothefis of pre-exiftent germs, on which modern philofophers differ fo much. To treat this important fubject with the attention it requires and deferves-he proposes,

[ocr errors]

Firft, To prove that the formation of organized bodies, fuch as plants and animals, could not be effected by laws merely mechanical or phyfical, and that therefore the hypothefis of the epigenefis is without any foundation: from whence it will appear, that the primitive germs of plants and animals prè exift in nature, as the elementary fubftances, above mentioned, exift previously to the formation of bodies in general.

Secondly, To fhew that the hypothefis of fome modern philofophers, who fuppofe thefe germs inclofed one within the other, is deftitute of all probability, and contrary to palpable facts: from whence he concludes that these germs are difperfed and diftributed throughout all nature, in the fame manner as other elementary substances.

Thirdly, To prove that there are laws prefcribed to the germs of organized bodies, by which the germ of each plant M m 2

and

and animal actually exifting must have been conveyed to the place where it has been developed.

From all which it will appear, that there is continually carried on in nature a procefs, fimilar and analagous to that which he supposes with refpect to the animated molecule, before its union with the animal body, and after its separation from it by death.

We fear that this feparation has hindered our learned Academician from executing this plan: if not-we shall give an account of it when it appears.

Philofophical Reflexions concerning Certainty. By M. de BEAUSOBRE. There are feveral fenfible things in this piece. It is upon the whole judicious and folid, and does honour to its author; but there is nothing in it that requires particular notice.

Concerning the Influence of Natural Caufes on the Mind of Man. By DOM. PERNETY.-An account of this ingenious memoir, as alfo of thofe that belong to the clafs of the Belles Lettres, will be given in our next Appendix.

ART. VI.

Hiftoire de l'Aftronomie Moderne depuis la Fondation de l'Ecole d'Alexandrie jufqu' à l'Epoque de 1730.-A Hiftory of Modern Aftro-nomy, from the Foundation of the Alexandrian School, to the Epocha of 1730. By M. BAILLY, of the Academy of Sciences at Paris. 2 Vols. 4to. With Cats. 1779.

IT

T is always with pleasure that we review the productions of this agreeable, acute, and truly learned Philosopher, who is inftructive and interefting even when he roams through the fields of fancy; who dreams like a man of genius; but who is peculiarly worthy of all our attention, when he walks in the real paths of hiftorical fact and philofophic fcience. In this refpectable point of view does he appear in the incomparable work before us, where we find the fame vaft erudition, the fame charms of eloquence, the fame elegance and brilliancy of ftyle, that have fo much diftinguifhed his former productions.

The parts of this work, which are purely aftronomical, and thofe difcuffions which are not immediately relative to the history and progress of that noble fcience, the reader muft perufe in the work itself; wherein he will find profound refearches and calculations, which would lofe their perfpicuity, and perhaps their precifion, in an abridgment. We therefore confine ourselves to the historical, which is the principal and the effential part of this work, and which will certainly be moft inftructive and entertaining to the generality of our Readers.

Nor

Nor has M. BAILLY loft fight of the lefs learned clafs of readers in the composition of this hiftory; he has admitted into it no more of the mathematical part of aftronomy than was neceffary to fhew the means by which difcoveries were made in that {cience.

Our Author is lefs bewildered in following the historical thread of this science, in modern times, where the path is beaten, where the facts are ascertained, and the dates are inconteftible, than he was, when he wandered in the devious wilds of ancient philofophical hiftory, in order to view the genuine afpects of aftronomical science, in the early ages. And though we admired the ingenious conjectures, by which he directed his course, for want of furer guides, and the almost magic power, with which he has thrown flashes of light upon the moft dubious objects, yet these flashes gave but a momentary evidence: we were ftill falling back into doubts and difficulties; and we are now very glad to follow him through a tract of time, where the road is as plain and luminous as the objects it represents are interefting and fublime.

The first volume of this excellent work is divided into ten books. The first five exhibit to us, fucceffively, all that is known of the school of Alexandria and of the aftronomers who preceded Hipparchus. This fchool, which was founded by Ptolemy Philadelphus, fubfifted near ten centuries. Though it was erected in Egypt, and that at a time when the sciences, encouraged by the munificence of that prince, and promoted by other concurring circumftances, flourished anew, yet it derived its principal luftre from the Greeks, who seemed deftined by nature to bring to perfection what others had invented, and who removed from aftronomical science the veil with which it had been covered by the Egyptian priests. It is certain (we follow the relation of M. BAILLY) that aftronomy appeared under a new aspect at this period. Obfervations of the heavenly bodies were made with inftruments, fufceptible of a certain degree of precision; hypothefes were formed to explain the motions of the planets; the progreffive motions of the stars were observed; their places were determined; and all these improvements were inferted by Hipparchus in a catalogue, that they might furnish points of comparifon to future ages.

Timocharis and Ariftillus are the first aftronomical obfervers we meet with in the school of Alexandria under Ptolemy Soter, about three hundred years before Chrift. Others there may have been that Hipparchus may have omitted. His work, entitled Almagest, or the Great Work, which contains all the attempts and improvements in aftronomical science that had been made in the fchool of Alexandria, was in fuch high efteem, that the fources from which he had taken his informaMm 3

tion

[ocr errors]

tion were almost entirely neglected.-About the fame time Aratus, the poet, was born at Solis, a town in Cilicia, and was employed by Antigonus, king of Macedon, to embellish with the charms of poetry all the branches of aftronomy that were then known.

The first aftronomer of note, who appeared in the Alexandrian school after these now mentioned, was Ariftarchus of Samos, contemporary of Cleanthes, a ftoic, who fucceeded Zeno, about the 129th Olympiad, or two hundred and fixtyfour years before Chrift. This philofopher applied himself to the most important branches of astronomy, and made a judicious choice among the ancient fyftems; but by adopting the hypothefis of the earth's motion, he ran counter to an opinion that had been rendered facred by the lapfe of ages, and by the veneration of the multitude; and accordingly, like Galilei, he was accufed of impiety, for having disturbed the repofe of Vesta, or the earth, and of the houshold gods, who made a part of her retinue. The phenomena of Euclid, which contributed much lefs to the luftre of his reputation than his elements of geometry, are not omitted by M. Bailly, nor even the jargon of the Egyptian conjurer Manethon, whofe work belongs rather to the vifionary fphere of divination and aftrology, than to the class of aftronomical productions.

Our Author does juftice in this hiftory to the celebrated librarian of Alexandria, Eratofthenes, who was called the furveyor of the univerfe, the cofmographer, and the second Plato. He was the first, in effect, who attempted to measure the earth; and the method he invented for this purpofe has rendered his name immortal. He was the inventor of the aftrolabe*, with which he undertook to measure the obliquity of the ecliptic; and it is fingularly remarkable, that the diftance of the fun from the earth, which he estimated at 804,000,000 ftadia, is exactly conformable to the diftance affigned by Meffrs. de Caffini and the Abbé de la Caille. The works that remain of this excellent poet, grammarian, mathematician, and aftronomer, were printed in an octavo volume, at Oxford, in the year 1672, and at Amfterdam in 1703. Archimedes, the contemporary of Eratosthenes, and the Newton of the Grecian school, deferved a place among the most celebrated aftronomers by his curious obfervation of the fun's diameter, and those which he made on the folftices; and Apollonius Pergæus, about the same time, acquired a high degree of fame, by his being the firft who attempted to explain the ftations and retrogradations of

The aftrolabe, which was anciently used for an affemblage of the various circles of the fphere, feems to have been pretty much of the fame nature with our armillary sphere.

« AnteriorContinuar »