Bi progress: its law and cause. 



Without committing ourselves to it as more than a speo 

 ulation, though a highly probable one, let us again com- 

 mence with the evolution of the solar system out of a ne- 

 bulous medium.* From the mutual attraction of the atoms 

 of a diffused mass whose form is unsymmetrical, there re- 

 sults not only condensation but rotation : gravitation simul- 

 taneously generates both the centripetal and the centrifugal 

 forces. While the condensation and the rate of rotation 

 are progressively increasing, the approach of the atoms ne- 

 cessarily generates a progressively increasing temperature. 

 As this temperature rises, light begins to be evolved ; and 

 ultimately there results a revolving sphere of fluid matter 

 radiating intense heat and light — a sun. 



There are good reasons for beheving that, in consequence 

 of the high tangential velocity, and consequent centrifugal 

 force, acquired by the outer parts of the condensing nebu- 

 lous mass, there must be a periodical detachment of rota- 

 ting rings ; and that, from the breaking up of these nebu- 

 lous rings, there must arise masses which in the course of 

 their condensation repeat the actions of the parent mass, 

 and so produce planets and their satellites — an inference 

 strongly supported by the still extant rings of Saturn. 



Should it hereafter be satisfactorily shown that planets 

 and satellites were thus generated, a striking illustration 

 will be afforded of the highly heterogeneous effects pro- 

 duced by the primary homogeneous cause ; but it will 

 serve our present purpose to point to the fact that from the 



would greatly encumber the argument to exemplify in connection with 

 the above, will be found developed in the essay on Transcendental Fhysio- 

 iogy. 



* The idea that the Nebular Hypothesis has been disproved because 

 what were thought to be existing nebulae have been resolved into clusters 

 of stars is almost beneath notice. A priori it was highly improbable, if 

 not impossil)le, that nebulous masses should still remain uncondensed, 

 while others have been condensed millions of years ago. 



