56 COSMOS. 



rests, when the agitation in which the lives of men wore 

 passed caused the geographical portion to be banished from 

 the history of nations, and raised into an independent 

 science. 



It remains to be considered whether, by the operation of 

 thought, we may hope to reduce the immense diversity of 

 phenomena comprised by the Cosmos to the unity of a prin- 

 ciple, and the evidence afforded by rational truths. In the 

 present state of empirical knowledge, we can scarcely flatter 

 ourselves with such a hope. Experimental sciences, based 

 on the observation of the external world, cannot aspire to 

 completeness; the nature of things, and the imperfection of 

 our organs, are alike opposed to it. We shall never succeed 

 in exhausting the immeasurable riches of nature; and no 

 generation of men will ever have cause to boast of having 

 comprehended the total aggregation of phenomena. It is only 

 by distributing them into groups, that we have been able, in the 

 case of a few, to discover the empire of certain natural laws, 

 grand and simple as nature itself. The extent of this empire 

 will no doubt increase in proportion as physical sciences are 

 more perfectly developed. Striking proofs of this advance- 

 ment have been made manifest in our own day, in the pheno- 

 mena of electro-magnetism, the propagation of luminous 

 waves and radiating heat. In the same manner, the fruitful 

 doctrine of evolution shows us how, in organic development, 

 all that is formed is sketched out beforehand, and how the 

 tissues of vegetable and animal matter uniformly arise from 

 the multiplication and transformation of cells. 



The generalization of laws, which being at first bounded by 

 narrow limits, had been applied solely to isolated groups of 

 phenomena, acquires in time more marked gradations, and 

 gains in extent and certainty, as long as the process of reason- 

 ing is applied strictly to analogous phenomena; but as soon 

 as dynamical views prove insufficient where the specific pro- 

 perties and heterogeneous nature of matter come into play, it is 

 to be feared that by persisting in the pursuit of laws we may 

 find our course suddenly arrested by an impassable chasm. 

 The principle of unity is lost sight of, and the guiding ^lue 

 is rent asunder whenever any specific and peculiar kind of 

 action manifests itself amid the active forces of nature. The 

 law of equivalents and the numerical proportions of eomposi* 



