I 



56 ON THE PROPERTIES OF MATTER, 



of a repulsive force in common matter has a great advantage in point of sim 

 plicity, and may perhaps hereafter be capable of proof, though at present it 

 can only be regarded, and was at first only offered, as an hypothesis. 



M. la Place, equally dissatisfied as Sir Isaac Newton with the idea of gravi- 

 tation being an essential property of matter, passes away from the inquiry 

 with suitable modesty, to practical subjects of far higher importance, and 

 whic'.: equally grow out of it, in whatever light it is contemplated. " Is this 

 principle," says he, " a primordial law of nature ? or is it a general effect of 

 an unknown cause ? Here we are arrested by our ignorance of the nature 

 of the essential properties of matter, and deprived of all hope of answering 

 the question in a satisfactory manner. Instead, then, of forming hypotheses 

 on the subject, let us content ourselves with examining more particularly the 

 manner in which philosophers have made -use of this most extraordinary 

 power."* 



There is, indeed, one very striking objection to Sir Isaac Newton's sugges- 

 tion, and which it seems very difficult to repel. It is, that though it may 

 account for the attraction of gravitation, as a phenomenon common to matter 

 in general, it by no means accounts for a variety of particular attractions 

 which are found to take place between particular bodies, or bodies particularly 

 circumstanced ; and which, excepting in one or two instances, ought, perhaps, 

 to be contemplated as modifications of gravitation. 



Upon these particular attractions, or modes of attraction, including homo- 

 geneous attraction, or the attraction of aggregation, heterogeneous attrac- 

 tion, or the attraction of capillary bodies, elective attraction, and those of 

 magnetism and electricity, each of which is replete with phenomena of a most 

 interesting and curious nature, I intended to have touched in the present lec- 

 ture, but our limited hour is so nearly expired, that we must postpone the 

 consideration of them as a study for our next meeting. Yet it is not possible 

 to close the observations which have now been submitted, without testifying 

 our gratitude to the memory of that transcendent genius whom the provi- 

 dence of the adorable Architect of the universe at length gave to mankind six 

 thousand years after its creation, to unravel its regular confusion, and reduce 

 the apparent intricacy of its laws to that sublime and comprehensive simpli- 

 city which is the peerless proof of its divine original. 



It has been said, that the discovery of the universal law which binds the 

 pebble to the earth, and the planets to the sun, which connects stars with 

 stars, and operates through infinity, was the result of accident. Nothing can 

 be more untrue, or derogatory to the great discoverer himself. The earliest 

 studies of Newton were the harbinger of his future fame : his mighty mind, 

 that comprehended every thing, was alive to every thing; the little and the 

 great were equally the subjects of his restless researches : and his attention 

 to the fall of the apple was a mere link in the boundless chain of thought, 

 with which he had already been long labouring to measure the phenomena 

 of the universe. 



Grounded, beyond all his contemporaries, in the sure principles of mathe- 

 matics, it was at the age of twenty-two that he first applied the sterling trea- 

 sure he had collected to a solution of the system of the world. The descent 

 of heavy bodies, which he perceived nearly the same on the summit of the 

 loftiest mountains and on the loweft surface of the earth, suggested to him 

 the idea that gravity might possibly extend to the moon ; and that, combined 

 with some projectile motion, it might be the cause of the moon's elliptic orbit 

 round the earth : a suggestion in which he was instantly confirmed by ob- 

 serving that all bodies in their fall describe curves of some modification or 

 other. And he further conceived, that if the moon were retained in her orbit 

 by her gravity towards the earth, the planets must also in all probability be 

 retained in their several orbits by their gravity towards the sun. 



To verify this sublime conjecture, it was necessary to ascertain two new 

 and elaborate positions : to determine the law of the progressive diminution 



Exposition du Systeme du Monde, liv. iv. ch. xv. 



