446 THE MULTIPLICATION OF EFFECTS. 



source of heterogeneity. The multiplication of effects must 

 proceed in geometrical progression. Each stage of evolu- 

 tion must initiate a higher stage. 



157. The force of aggregation acting on irregular 

 masses of rare matter, diffused through a resisting medium, 

 will not cause such masses to move in straight lines to their 

 common centre of gravity; but, as before said, each will 

 take a curvilinear path, directed to one or other side of the 

 centre of gravity. All of them being differently condi- 

 tioned, gravitation will impress on each a motion differing 

 in direction, in velocity, and in the degree of its curvature 

 uniform aggregative force will be differentiated into 

 multiform momenta. The process thus commenced, must 

 go on till it produces a single mass of nebulous matter ; and 

 these independent curvilinear motions must result in a 

 movement of this mass round its axis: a simultaneous con- 

 densation and rotation in which we see how two effects of the 

 aggregative force, at first but slightly divergent, become at 

 last widely differentiated. A gradual increase of oblateness 

 in this revolving spheroid, must take place through the joint 

 action of these two forces, as the bulk diminishes and the ro- 

 tation grows more rapid ; and this we may set down as a third 

 effect. The genesis of heat, which must accompany aug- 

 mentation of density, is a consequence of yet another order 

 a consequence by no means simple; since the various 

 parts of the mass, being variously condensed, must be vari- 

 ously heated. Acting throughout a gaseous spheroid, of 

 which the parts are unlike in their temperatures, the forces 

 of aggregation and rotation must work a further series of 

 changes : they must set up circulating currents, both general 

 and local. At a later stage light as well as heat will be gen- 

 erated. Thus without dwelling on the likelihood of chemi- 

 cal combinations and electric disturbances, it is sufficiently 

 manifest that, supposing matter to have originally existed in 

 a diffused state, the once uniform force which caused its 





