. 229. THEORY OF THE SYSTEM. 341 



The nature of these ideas evidently depends upon the 

 preceding observations. If, therefore, in general, and 

 from reasons of Natural History, no objection can be made 

 to the ideas of the species, the genus, the order, or the 

 class ; the applicability of the mineral system, arising 

 from the connexion of these ideas, will depend solely 

 upon their consistent application to the present state of 

 knowledge. 



To apply the ideas of the species, the genus, &c. to 

 experience, is to collect the individuals occurring in na- 

 ture, agreeably to their homogeneity, into species ; to join 

 these species into genera, according to the highest de- 

 gree of natural-historical resemblance which occurs among 

 them, &c. ; or, in other words, accurately to determine 

 the more particular contents of the system. This sup- 

 poses an accurate examination and a careful comparison 

 of the individuals among each other ; and in that respect 

 the only mode in which the mineral system may arrive 

 at its perfection, is by a thorough knowledge of the ob- 

 jects themselves. This knowledge, however, being an em- 

 pirical one, must always remain incomplete, and is really 

 so at present in a great measure : a perfect mineral sys- 

 tem, therefore, is an object, which, though we may ap- 

 proach, we never can reach. 



We must proceed with some caution in thus determin- 

 ing the contents of the mineral system : a few rules in this 

 respect will not be superfluous. The first of these rules 

 requires, that we attach the highest importance to the 

 correct determination of the species, because this is the 

 foundation of all the other ideas, and therefore of the sys- 

 tem itself. According to another of these rules, we must 

 endeavour to unite newly discovered individuals, along 

 with other species already determined, till we may con- 

 vince ourselves by an accurate examination, that this is no 

 longer possible ; because it is a general rule in Natural 

 History not to multiply the number of the species, without 

 an evident necessity. In fact, one of the greatest errors 

 of many mineral systems consists in their containing too 



