. 15. INTRODUCTION. 11 



which, in their natural state (. 3.), do not differ from each other 

 in any of their properties ; and this may be considered as an 

 Axiom in Natural History. This mode of reasoning is com- 

 mon to all the three parts of the science. There occur, 

 however, differences in respect to the application of these 

 ideas to Nature. They arise out of the different qualities 

 of the natural productions contained in each of the King, 

 doms. 



The possibility of introducing mathematical ideas into 

 the Terminology of the Mineral Kingdom, is particularly 

 beneficial to the establishment of these systematic ideas, 

 in as much as their precision, in some measure, extends to 

 the latter ; and imparts to the most important of them 

 all, to the Idea of the Species, a degree of evidence, which 

 seems to be wanting in the other kingdoms, both vegetable 

 and animal, and which it is scarcely possible to supersede 

 by any other considerations. In this part of Natural His. 

 tory, the Theory of the System takes the place of the 

 Axioms and Theorems of Geometry. 



The name of Classification has been sometimes applied 

 to the systematic reasonings in Natural History. Yet, 

 properly speaking, classification is only that part of the 

 Theory of the System which refers to the idea of genera, 

 orders, &c. under which the species shall be finally ar- 

 ranged, and in their application to Nature. 



. 15. NOMENCLATURE. 



Nomenclature, is the assemblage of rules, ac- 

 cording to which Names and Denominations are 

 applied to natural productions. By these names 

 and denominations, the ideas of the system are 

 fixed ; or the one can be substituted as representa^ 

 tives instead of the other. 



The scientific nomenclature in Natural History is syste- 

 matical. Any nomenclature, not systematical, is termed a 

 trivial nomenclature, and does not belong to the science. 



