. 577 they quarrelled among themselves at home; and among other acts of barbarity, they treated their flaves with peculiar harth. nefs and severity. Thefe internal diforders rendered the code of Jarofaf neceffary. This volume brings down the ancient hiftory of Ruffia to the year 1236, when the Megul Tartars made themselves mafters of the empire, and kept the Ruffians under a grievous and tyrranical yoke for above two centuries. It is terminated by an inquiry into the origin and caufes of this great revolu tion. A fpirit of ambitious frenzy, producing hatred, vengeance, and the hoftile paffions, that degrade human nature and civil fociety, had feized upon almost all the Ruffian princes. The fovereigns of Kiof confidered their fubjects as their flaves (and is it much other wife in better times?) 1 he other princes were all aipiring after the fupreme authority. The nobles and magiftrates, following the example of their fuperiors, exercised tyrannical oppreffion in their spheres. Hince internal difunion and diforder, which ever produce weakness, and expose a nation to fail before the first powerful invader! The firf volume of the Modern History fhall be reviewed in a future Article. ART. IV Physique du Monde, i. e A Colmologica Sem of Natural Philofo phy; or A Phyfical Syftem of the Univerfe By the Baron DE M RIVETZ, and M. GoUSSIER. Vo. II. 4to. Paris. 1782. In the of the of N the preceding volume of this ingenious work, the Authors attempted to prove, that none of the lyftems of Cofinogony hitherto exhibited, furnish a true and philofophical account of the origin and conttiturion of our terreftrial globe. The motions of the celeftial bodies remain equally unaccounted for; and the molt eminent aftronomers of the prefent age have unanimously confidered the revolutions of the planets, the velocity with which they move in their oroits, their varying distances from the fun, and their rotation on their own axes, as phoenomena, deducible from no mechanical caufes, known to us. — They go ftill farther, and allege, that thefe unknown caufes are not connected with the general fyftem of the universe t• Our Authors do not relish this doctrine: the caufes may be yet * For an account of the first volume, fee Review for March 1793, page 200. Hi motus (fays the father of modern philofophy) originem non habent ex caufis mechanicis. The celebrated M Dionis du Sejour and M. de la Lande, hold the fame language, the former in his Ejay toncerning Comets, and the Prelim. Difcourfe, p. 20. and p 330.; and the latter in his Aftronomy, Vol. III. p. 385. unknown; unknown; but how, fay they, can a general fyftem be conceived, in which the most important and general phoenomena, those which give rife to all others, are fuppofed to be inde pendent on that fyftem? Our Authors confider the world as a great machine; and as there cannot be in any machine a fingle movement that does not refult from mechanical laws, they boldly bring forth the doctrine of one fimple, primitive, general power or force, from which is derived all action; while action, in all its forms and modifications, obeys the laws originally prescribed to matter and motion. With this philosophical key, our Authors proceed, in the fecond volume, now before us, to open the celeftial manfions, and give us fome nearer views of what is going on there, than have been prefented by former peepers into the ftarry region. It is certain that our Authors peep fublimely, and, to use Pope's famous fimilitude, we do not doubt but that celeftial beings behold the apes with a smile of complacence.-The firft part of this volume contains (what our Author calls) the PhiloJophy of the Heavens, in which he confiders fucceffively space, or the ethereal medium-the fun-the planets, with their fatel lites-the diftinctive characters, place, light, and appearances of the comets, together with the obfervations that have been made on them, and the hiftory of the opinions of the learned concerning them-the ftarry heavens-the nebulous and double ftars-the phænomena obferved in the fixed ftars-the light of the ftars-the milky way-density and gravitation-the law by which the celeftial bodies are governed, and the organization (as our Author calls it) of the vortex of our globe. To give our Readers, in as fmall a compafs as is poffible, a general notion of our Author's theory of the celestial bodies, we muft fet out by obferving, that he denies the existence of a vacuum, or void, in the univerfe; and labours, with great learning and fagacity, to establish the doctrine, not of the dense medium of Des Cartes, but of an eminently elaftic fluid, filling the immenfe capacity of infinite fpace. In this fluid the Creator diffeminated, by an act of his will, innumerable spheres of different magnitudes. The greater, defigned to rule the motions of the leffer, were made to occupy centres, and were commanded by the MOST HIGH to revolve about their own axes; then they imprinted their motion on the furrounding fluid; and the fmaller fpheres plunged in this fluid, and bitherto at rest, were carried by its motion around the central sphere (refpectively), by which their revolutions were to be directed; the central fphere, by its movement of rotation, rubbing with rapidity the infinitely elaftic molecules of the fluid, excited in it vibrations: thefe vibrations, propagated through space among the contiguous molecules, ftruck all the globes suspend ed ed in it, only on the parts of their surface that were turned towards the central fphere, from which they derived their motion; thefe folid furfaces fent back, by repercuffion, the vibrating molecules, and from this fhock arofe a general splendour.Thus the central moving globes became funs; and then Matter received its motion, Time its measure, Light appeared, and Nature arose into birth. Then the eternal series of whatever was to exist, received the Law that was to regulate all the moments, changes, and events, of their duration. The whole, then, of our Author's fyftem, as he obferves himself, may be comprehended in the nine following Propofitions, which we shall here give in his own words: I. The Sun turns around his own Axis in a Fluid eminently Elaftic. II. The Sun cannot turn on his own Axis, in this Fluid, without communicating to it his Motion, and without making it turn round him.-III. The general Fluid, in turning round the Sun, carries along with it the Planets, of which the Sun becomes the Director. Here we see the reason why all the planets turn in the fame direction with the fun.-IV. The Velocities of the Orbs of this Fluid are not equal, at unequal diflances from the Sun. Hence the planets move in their orbits with a velocity, which diminishes in proportion to their distance from the fun.-V. The Motion, imprinted on the Fluid by the Equator, is more rapid than that which is imprinted on the fame Fluid by any other of the Solar Circles, taken between his Equator and his Poles: this greater Velocity of the impelling Fluid, in the Plane of the Sun's Equator, de termines the Planets to move towards that Plane. This is the reason why the planets all turn in a band, or zone, exceedingly narrow, and in almoft the fame plane, which differs little from that of the folar equator.-VI. The Planets do not follow the line of the greatest Velocity of the Fluid, because they receive lateral Impreffions; thefe Impreffions refult from the Vibrations of the Ether towards the production of Light; vibrations which the Planets communicate by Repercuffion, one to another. This is the reafon of the obliquity of their orbits to the fun's equator, and alfo of the elliptical form of thefe orbits. This elliptical form is a neceffary confequence of the fucceffive paffage of the planets through the different folar orbs, or vortexes, which have different velocities.-VII. The Planets carried along with the general Vortex, and interfecting obliquely, and twice in each of their Revolutions, the Plane of the Sun's Equator, must confequently defcribe Ellipfes about the Sun, and therefore pass at different Dif tances. Of thefe Distances, the leaft of all is called the Perihelium, and the greatest the Aphelium. The Planets, in their Perihelium, being plunged in Orbs lefs diftant from the Sun, must receive from theje Orbs a greater Velocity. This is the reafon why the mo tion of the planets grows more rapid at their perihelium.-VIII. The vibrating motion of the Ether to a state of Light. acts more powerfully upon the Planetary Bodies, than does the general orbicu lar Motion, or circulation of that Æther: this action is not equal, or the fame upon the different Points of the enlightened Hembere of the Planet, because that Hemisphere is plunged in Orbs, unequally diftant from the Sun. This is the reason why the planets turn on their own axes, and all in the fame direction.-IX. The larger a Planet is, the more the action of Light varies, on the twe Oriental and Occidental halves of the enlightened Hemisphere of that Planet. This is the reafon why the larger the panets are, the greater is the rapidity of their motion round their own axes. We must refer our Readers to the work itfelf for the ample illuftrations, which are here given, of these nine propositions, and the very learned and ingenious manner in which they are adapted to facilitate the explication of the various phoenomena. We shall only obferve, with respect to the eminently elaftic fluid, that forms a plenum in infinite space, and acts fuch a capital part in the fyftem now before us, that our Authors will not allow it to be looked upon as an exploded hypothefis. They pretend, that no philofopher of any authority has maintained the doctrine of an abfolute vacuum, or void, in nature. They allege, that the Newtonian school has been erroneously appealed to in favour of this doctrine. They affirm and prove, that its immortal Head neither faid nor believed, that the interplanetary space was an abfolute void, but that he confidered it as filled with a fluid, eminently elaftic, eminently expanible, and four hundred and ninety thoufand millions of times more elastic than the air of our at mofphere. That fuch a fluid fhould be capable of receiving and tranfmitting motion, is not a matter of wonder; but that it fhould abfolutely fill univerfal and infinite fpace, i- a point that may ftagger the philofophical faith of many; as a univerfal plenum is pretty generally looked upon as a glaring hurely in phylics. We ourselves were of this opinion, and we are not over difpofed to give it up; yet there is fuch perfpicuity, precision, and force in the arguments of M. de MARIVETZ, that we are totally unable to answer them. We fhall, therefore, leave that matter to abler hands, to whofe perufal and attention we venture to recommend them. In the fecond part of this volume our Authors explain the numerous plates that are defigned to prove and illufrate the various branches of their doctrine relative to the celeftial bodies. They alfo exhibit direct and geometrical proofs of the principles from which their whole theory is derived, for the fatisfaction of the learned part of their readers, who may not have been convinced by the more popular (though (though we think very ingenious arguments employed in the preceding part. Here the mathematical aftronomer will find details, which fhew M. de MARIVETZ to be completely mafter of his noble fubject, and will admire the fimplicity, precifion, and perfpicuity that accompany his proofs and explications. The plates, which are FIVE in number, contain above forty figures. The first plate represents the Mundane Syftem, on the plane of the ecliptic. The fecond, which contains five figures, and a table of the lunations of the year 1780, reprefents the motion, or rather the refpective fituations of the earth and the moon around the fun, at the times of the new and full moons, and at the quadratures. The third and fourth exhibit the internal organization of the folar vortex, and the different motions of the æther of the vortex, determined by the fun's rotation. The fifth contains the relative magnitudes of the fun, and of the principal planets, as also those of the apparent orbits, which the fatellites, or fecondary planets, feem to defcribe about their respective planets, proportional to each other, and to a scale of fixteen hundred thousand (French) leagues, which is engraven at the bottom of the plate. In the explication of the fourth plate, our Authors give an interefting illuftration, and proof, of the eighth propofition mentioned above, as unfolding the true caufe of the rotation of the planets about their axes. The efficient, mechanical caufe of this rotation has not been explained hitherto by any of the authors that have treated this fubject. It is true, that the New Conjectures of M. de MAIRAN, concerning the Diurnal mition of the Earth from Weft to Eaft, publifhed in the Memoirs of the Royal Academy of Sciences at Paris, for the year 1729, may be confidered as an ingenious attempt towards the explication of this phoenomenon; but our Authors fhew, that M. de Mairan's account of the matter is attended with unfurmountable difficulties, and that the hypothefis of Mr. John Bernoully is equally unfatisfactory. They alfo fhew, by a series of proofs, that the true cause of the rotation of the planets, is the inequality of the impulfive force of the folar rays, or æther, on the two halves of (or in the different orbs that correfpond with) the enlightened hemifphere of the planet. Notwithstanding the vast knowledge of nature, the extensive learning, the logical precifion, the warmth, elegance, and perfpicuity of expreffion, that have already rendered this excellent. work an object of general attention and efteem, it contains feveral opinions and novelties that w II not efcape the eagle eyes of philofophical critics. The banishment of attraction from the mechanifm of the univerfe, and particularly from the theory of the moon-the confideration of comets, as neither folid nor permanent fubftances, but mere luminous phoenomena-the ad I milion |