THE LAW OF EVOLUTION CONCLUDED. 395 



ly widening dispersion, more disintegrated, the motion that 

 is for a time retained, becomes more integrated; and so, 

 considered dynamically, Evolntion is a decrease in the rela- 

 tive movements of parts and an increase in the relative 

 movements of wholes — using the words parts and wholes 

 in their most general senses. The advance is from the 

 motions of simple molecules to the motions of compound 

 molecules ; from molecular motions to the motions of masses ; 

 and from the motions of smaller masses to the motions of 

 larger masses. The accompanying change towards 



greater multiformity among the retained motions, takes 

 place under the form of an increased variety of rhythms. 

 We have already seen that all motion is rhythmical, from 

 the infinitesimal vibrations of infinitesimal molecules, up 

 to those vast oscillations between perihelion and aphelion 

 performed by vast celestial bodies. And as the contrast 

 between these extreme cases suggests, a multiplication of 

 rhythms must accompany a multiplication in the degrees 

 and modes of aggregation, and in the relations of the aggre- 

 gated masses to incident forces. The degree or mode of 

 aggregation will not, indeed, affect- the rate or extent of 

 rhythm where the incident force increases as the aggregate 

 increases, which is the case with gravitation: here the only 

 cause of variation in rhythm, is difference of relation to the 

 incident forces; as we see in a pendulum, which, though 

 unaffected in its movements by a change in the weight of 

 the bob, alters its rate of oscillation when taken to the 

 equator. But in all cases where the incident forces do not 

 vary as the masses, every new order of aggregation initiates 

 a new order of rhythm : witness the conclusion drawn from 

 the recent researches into radiant heat and light, that the 

 molecules of different gases have different rates of undula- 

 tion. So that increased multiformity in the arrangement of 

 matter, necessarily generates increased multiformity of 

 rhythm; both through increased variety in the sizes and 

 forms of aggregates, and through increased variety in their 



