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This friendly mixture and alliance of Phy, fics and Mathematics, from which so much honour and advantage are derived to the cause of physical truth, is a piece of fine philosophy, which, whether it was fpeculately understood by the great Newton, whose labours, founded on the connection, produced so many splendid discoveries, is well explained by Aristotle, whose Physics are little better than a heap of vain hypotheses -- an illustrious proof, that the perfection of science is never to be raised from its foundation by the exertions of a single genius, however powerful and extensive ; but must advance, through several stages of improvement, on the labours of many: at the same time that it is a pointed admonition to every later philosopher, to avail himself of the discoveries of his predecessors.

ai quot;, ste: gargas Tã quá xao, ở tại T8 tỷ U-goidra' ti wipi tã é au soir, de aspi ixatigas. Mótepor cu sñs autñs, ñ ärans, fx alépær guwprstov. Aristot. Auscult, Natural. lib. ii. cap. 2.

& See Nat. Auscult. lib. ii, cap. 2,

It is, however, a truth to be acknowledged and lamented, that the genius of one philosopher being either insensibly warped or voluntarily enslaved by the authority of another, is a circumstance which has often thwarted the advancement of knowledge, and always proved an insurmountable obstacle to the progress and success of learning : and one of the most difficult and important tasks under which every improver of science has to labour, however independent in his spirit and ingenuous in his views, is to know, what of the works of his predecessors to adopt, and what to reject. This is a field which it is necessary to cultivate, but which is of most critical and important determination ; in which judgment is often embarrassed, and genius perplexed ; and in which memory and prejudice too often usurp their place : and, fince he put in execution the precepts, and followed the directions of the organum of an abler logician, we may have cause to rejoice upon the whole, that our great English philosopher was no more conversant in the works of the Peripatetic,

It was neither from the Principles nor Reasoning, neither from the Logic or Practice of Aristotle, (which two last seldom, if ever, coincided in effect,) that Newton astonished the world with such a brilliant train of Astronomical discoveries and calculations; which, in addition to the other philosophical inventions and improvements of that extraordinary genius, whilst they reflect the highest honour on the country which gave him birth and education, have immortalized his name and memory. The Logic, which directed his physical researches, pointed out to him a more humble and laborious, but a more honourable and successful, road to truth. From the ingenious fictions and plausible inventions of the Stagyrite, and from the formal but feeble disputations of his weaker followers, it brought hiin down to the lạboạr of experiment and actual observation. Out of the wilds of imagination, it led him to cultivate the field of nature : and from mental speculations, it drew down his attention to manual operations.


By Experiments ingeniously made and accurately observed, he took the true phænomena arep of Motion as generated by the powers of Gravity, Elasticity, the Resistence of fluids and the like ; and analysed the Forces by which it is produced, and of which it is compounded." To these Forces be applied his sublime Geometry, which science he advanced much beyond the farthest reach of all former mathematicians, and by which he demonstrated the phænomena of all the Curves described, and Motions performed by Projectiles, in every hypotheses that could be framed.

From the astronomical Observations of Copernicus and the Rules and conjectures of Kepler, two of the ableft astronomers before him, he found the Planets revolving round their respective centres in Curves and Motions

* All improvement in learning is progressive ; and phim, losophers are never dishonoured by availing themselves of the inventions of their predecessors or contemporaries, Galilæo observed the velocity of falling bodies to increase in the duplicate ratio of the time; and that Projectiles move in a Parabola : and Sir Christopher Wren found the equability of motion by experiments on pendulums. See the Scholium At the end of the sixth Corollary of Newton's Principia.


exactly SIMILAR or the SAME ; and by a bold and sublime ANALOGY,' which made him the first astronomer in the world, from his theory of Projectiles, experimentally founded and geometrically confirmed, he raised his philosophy to the celestial Bodies,"

Non a Naturæ Analogia recedendum eft, cum ea fimplex elle soleat, et fibi consona,-et hoc est fundamentum Philosophiæ totius. Newtoni Regula Philosophandi, lib, iii. Princip.

Conclusiones precedentes huic innituntur Axiomati • Effectuum scilicet ejusdem generis, quorum nempe quæ

cognofcuntur proprietates eædem sunt, eafdem effe caufas 6 et eafdem esse proprietates quæ nondum, cognoscuntur' &c.—In hac regula fundatur omnis philosophia, quippe, qua fublata, nihil affirmare possemus de universis, Cotefii Præf. in Newtoni Princip.

► Eadem ratione qua Projectile vi gravitatis in orbem flecti posset et terram totam circumire, potest et Luna vel vi gravitatis, fi modo gravis fit, vel alia quacunque vi qua in terram urgeatur, retrahi semper a cursu rectilineo terram versus et in orbem suum fecti; et absque tali vi Luna in orbe fuo reteneri non poteft. Hæc vis, fi justo minor effet, non satis Alecteret Lunam a cursu rectilineo: si justo major, plus fatis flecteret, ac de orbe terram versus deduceret. Requiritur quippe ut sit juftæ magnitudinis : et Mathematicorum est invenire Vim, qua corpus in dato quovis orbe data cum velocitate accurate retineri possit ; et viciffim invenire Viam curvilineam, in quam corpus e dato quovis loco data cum velocitate egressum data vi flectatur. Newa toni Principio Mathem. Def, v.


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