74 COSMOS 



ing is applied strictly to analogous phenomena ; but as soon 

 as dynamical views prove insufficient where the specific prop- 

 erties 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 clew 

 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 composi- 

 tion, so happily recognized by modern chemists, and proclaimed 

 under the ancient form of atomic symbols, still remains isola- 

 ted and independent of mathematical laws of motion and grav- 

 itation. 



Those productions of nature w^ich are objects of direct ob- 

 servation may be logically distributed in passes, orders, and 

 families. This form of distribution undoubtedly sheds some 

 light on descriptive natural history, but the study of organized 

 bodies, considered in their linear connection, although it may 

 impart a greater degree of unity and simplicity to the distri- 

 bution of groups, can not rise to the height of a classification 

 based on one sole principle of composition and internal organ- 

 ization. As different gradations are presented by the laws 

 of nature according to the extent of the horizon, or the limits 

 *of the phenomena to be considered, so there are likewise dif- 

 ferently graduated phases in the investigation of the external 

 world. Empiricism originates in isolated views, which are 

 subsequently grouped according to their analogy or dissimilar- 

 ity. To direct observation succeeds, although long afterward, 

 the wish to prosecute experiments ; that is to say, to evoke 

 phenomena under different determined conditions. The ra- 

 tional experimentalist does not proceed at hazard, but acts 

 under the guidance of hypotheses, founded on a half indistinct 

 and more or less just intuition of the connection existing among 

 natural objects or forces. That which has been conquered 

 by observation or by means of experiments, leads, by analysis 

 and induction, to the discovery of empirical laws. These are 

 the phases in human intellect that have marked the different 

 epochs in the life of nations, and by means of which that great 

 mass of facts has been accumulated which constitutes at the 

 present day the solid basis of the natural sciences. 



Two forms of abstraction conjointly regulate our knowl- 

 edge, namely, relations of quantity, comprising ideas of num- 

 ber and size, and relations of quality, embracing the consider- 

 ation of the specific properties and the heterogeneous nature 



