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 



