330 THEORY OF THE SYSTEM. . 22 



the advantage of similar classifications, and those depart- 

 ments of Natural History which refer to them, have long 

 ago made a scientific progress. In the Mineral Kingdom, 

 unfortunately, a different way has been proceeded upon ; 

 and as a science, the Natural History of the Mineral King- 

 dom has not been promoted. 



In the Natural History of the Mineral Kingdom, the 

 classifiable objects are not the individuals of this kingdom ; 

 but according to the preceding inquiries, the natural-histo- 

 rical species (. 220.). The natural-historical resemblance 

 has therefore nothing to do with individuals. These, in- 

 deed, notwithstanding their homogeneity, bear in many 

 instances so little resemblance to each other, that accord- 

 ing to the principle of similarity, they rather should be 

 divided than joined. It becomes necessary indeed to demon- 

 strate their connexion by means of the transitions, that 

 is to say, by considering their series of characters, in order 

 to convince ourselves of their homogeneity. Hence the 

 two ideas of Resemblance and of Homogeneity are essentially 

 different, and the former is not a higher degree, or a nearer 

 restriction of the latter. We must carefully avoid con- 

 founding them with each other. In another science, refer- 

 ring to the Mineral Kingdom, another principle of classi- 

 fication may replace the natural-historical resemblance ; 

 but there is not another idea which can be substituted for 

 that of homogeneity. 



. 224. DEGREES OF NATURAL-HISTORICAL RESEM- 

 BLANCE. 



The degrees of natural-historical resemblance 

 in different species, are not everywhere the same. 



If we consider the species as unities to be classified, and 

 compare them with each other in respect to their natural- 

 historical properties ; we perceive that some of them are 

 more, some of them less allied to each other in resemblance. 

 Thus hexahedral Iron-pyrites is more similar to prismatic 



