INTRODUCTION. 23 



*he existence of inhabitants in the moon, th;m of those in 

 the remoter planets, which he assumes to be " surrounded with 

 vapours and clouds." 



The immortal author of the Philosophies Naturalis Principia 

 Mathematica (Newton) succeeded in embracing the whole 

 uranological portion of the Cosmos in the causal connexion of 

 its phenomena, by the assumption of one all-controlling fun- 

 damental moving force. He first applied physical astronomy 

 to solve a great problem in mechanics, and elevated it to the 

 rank of a mathematical science. The quantity of matter in 

 every celestial body gives the amount of its attracting force ; a 

 force which acts in an inverse ratio to the square of the distance, 

 and determines the amount of the disturbances, which not only 

 the planets but all the bodies in celestial space exercise on 

 each other. But the Newtonian theory of gravitation, so 

 worthy of our admiration from its simplicity and generality, 

 is not limited in its cosmical application to the uranological 

 sphere, but comprises also telluric phenomena, in directions 

 not yet fully investigated ; it affords the clue to the periodic 

 movements in the ocean and the atmosphere ; w and solves the 

 problems of capillarity, of endosmosis, and of many chemi- 

 cal, electro-magnetic, and organic processes. Newton, 39 

 even distinguished the attraction of masses, as manifested in 

 the motion of cosmical bodies and in the phenomena of 



38 See Laplace (des oscillations de I' atmosphere, du flux 

 solaire et lunaire] in the Mecanique Celeste, livre iv. and in the 

 Exposition du Syst. du Monde, 1824, pp. 291-296. 



39 Adjicere jam licet de spiritu quodam subtilissimo corpora 

 crassa pervadente et in iisdem latente, cujus vi et actionibus 

 particulse corporum ad minimas distantias se mutuo attrahunt 

 et contiguse factse cohaerent. Newton, Principia Phil. Nat. 

 (ed. Le Sueur et Jacquier, 1760) Schol. gen., t. iii. p. 676, 

 compare also Newton's Opticks, (ed. 1718). Query 31, pp. 

 305, 353, 367, 372. (Laplace, Syst. du Monde, p. 381, and 

 Cosmos, p. 44.) 



