XL] <M0gkaI grfbrm. 239 



themselves a good deal upon the practical sense and 

 wisdom of this proceeding. As a temporary measure, I 

 do not presume to challenge its wisdom; but in all 

 organized bodies temporary changes are apt to produce 

 permanent effects ; and as time has slipped by, altering 

 all the conditions which may have made such mortifica- 

 tion of the scientific flesh desirable, I think the effect of 

 the stream of cold water which has steadily flowed over 

 geological speculation within these walls has been of 

 doubtful beneficence. 



The sort of geological speculation to 'which I am now 

 referring (geological aetiology, in short) was created, as 

 a science, by that famous philosopher Tmmanuel Kant, 

 when, in 1755, he wrote his " General Natural History 

 and Theory of the Celestial Bodies ; or an Attempt to 

 account for the Constitution and the Mechanical Origin 

 of the Universe upon Newtonian principles." 1 



In this very remarkable but seemingly little-known 

 treatise, 2 Kant expounds a complete cosmogony, in the 

 shape of a theory of the causes which have led to the deve- 

 lopment of the universe from diffused atoms of matter 

 endowed with simple attractive and repulsive forces. 



" Give me matter/' says Kant, " and I will build the 

 world;" and he proceeds to deduce from the simple 

 data from which he starts, a doctrine in all essential re- 

 spects similar to the well-known " Nebular Hypothesis" 

 of Laplace. 3 He accounts for the relation of the masse$ 

 and the densities of the planets to their distances from 

 the sun, for the eccentricities of their orbits, for their 

 rotations, for their satellites, for the general agreement 



1 Grant (" History of Physical Astronomy," p. 574) makes but the briefest 

 reference to Kant. 



* " Allgemeine Natnrgeschichte tmd Theorie des Himmels ; oder Versuch 

 von der Verfassung und dein mechanischen Ursprunge des ganzen Weltge- 

 biiuded nach Newton'schen Grundsatzen abgehandelt." KANT'S tiammtliche 

 Werke, Bd. i. p. 207. 



s Systeme du Monde, tome ii. chap. 6. 



