396 THE LAW OF EVOLUTION CONCLUDED. 



relations to the forces which move them. That 



these motions as they become more integrated and more 

 heterogeneous, must become more definite, is a proposition 

 that need not detain us. In proportion as any part of an 

 evolving whole segregates and consolidates, and in so doing 

 loses the relative mobility of its components, its aggregate 

 motion must obviously acquire distinctness. 



Here, then, to complete our conception of Evolution, we 

 have to contemplate throughout the Cosmos, these meta- 

 morphoses of retained motion that accompany the meta- 

 morphoses of component matter. We may do this with 

 comparative brevity: the reader having now become so far 

 familiar with the mode of looking at the facts, that less illus- 

 tration will suffice. To save space, it will be convenient to 

 deal with the several aspects of the metamorphoses at the 

 same time. 



§ 140. Dispersed matter moving, as we see it in a spiral 

 nebula, towards the common centre of gravity, from all 

 points at all distances with all degrees of indirectness, must 

 carry into the nebulous mass eventually formed, innumera- 

 ble momenta contrasted in their amounts and directions. As 

 the integration progresses, such parts of these momenta as 

 conflict are mutually neutralized, and dissipated as heat. 

 The out-standing rotatory motion, at first having unlike 

 angular velocities at the periphery and at various distances 

 from the centre, has its differences of angular velocity 

 gradually reduced; advancing towards a final state, now 

 nearly reached by the Sun, in which the angular ve- 

 locity of the whole mass is the same — in which the motion 

 is integrated. So, too, with each planet and satel- 



lite. Progress from the motion of the nebulous ring, inco- 

 herent and admitting of much relative motion within its 

 mass, to the motion of a dense spheroid, is progress to a mo- 

 tion that is completely integrated. The rotation, and the 

 translation through space, severally become one and indivis- 



