Ixxx KANT'S UNIVERSAL NATURAL HISTORY 



place from the Nebular disc of our Solar System 

 already in rotation. Kant makes suns and planets 

 arise out of certain regions of space, through gravi- 

 tation ; Laplace makes masses and rings detach 

 themselves from the central body, through centri- 

 fugal force. Only in the case of Saturn does Kant 

 make rings arise from the central body " through 

 evaporation," in which case the vapours retain their 

 tangential swing. Otherwise he assigns to every 

 celestial body a certain zone of the vaporous space, 

 out of which the matter is condensed into it. It 

 is otherwise with Laplace, who starts from the con- 

 traction of the central body, with which its rotation 

 must increase until the centrifugal force has become 

 equal to the centripetal force, when with further 

 contraction a ring shall then be detached ; and this 

 process is repeated several times. We hear often, 

 perhaps from convenience, of a Kant-Laplace 

 Cosmogony ; l but the difference between them is 

 sufficiently great, to keep the views distinct and 

 separate/ 2 We may also quote Mr. G. F. Becker's 

 statement of the main points of comparison between 

 Kant and Laplace : Kant begins with a cold 

 stationary Nebula, which, however, becomes hot by 

 compression, and at its first regenesis would be in 

 a state of rotation. It is with a hot, rotating 

 Nebula that Laplace starts, without any attempt to 



1 Helmholtz used this designation. So too F. Kerz in his Platidereien 

 iiber die Kant- Laplace' sche Nebiilarhypothese, 1887. 

 2 Ostwald's Klassiker Nr. 12, p. 150. 



