362 NOMENCLATURE. . 239- 



ture, which refers to a natural or synthetical system, to create 

 an image of the object to which it refers, hy means of its de- 

 nominations, which never can be erroneous, though it may 

 be insufficient. The trivial nomenclature can never render 

 this service, how perfect soever it may be in respect to its 

 peculiar properties. If we hear the name Jlutlle, and do not 

 know the species itself, to which it belongs, we never can 

 imagine any thing like a representation of the object, 

 though for the rest, our knowledge of Mineralogy may be 

 very extensive. If, on the contrary, we hear peritomous 

 Titanium-ore, and have only an idea of the order Ore, this 

 at once will produce a general image of the species, which 

 will be still more restricted, if we have some idea of the 

 genus Titanium-ore. But we may indeed suppose that every 

 person possesses an image of the orders and genera in his mind, 

 who is in some degree acquainted with the Natural History of 

 the Mineral Kingdom. If, besides, we attend to the cleav- 

 age, which is peritomous, this will suffice, by the mere de- 

 nomination, for distinguishing the varieties of peritomous 

 Titanium-ore from those of the prismatic or the pyrami- 

 dal Titanium-ore. The denominations may be still more 

 useful, if they express the cleavage more minutely, or if 

 they refer to the system of crystallisation. By the deno- 

 mination hexahedral Iron-pyrites we learn, that in the 

 order Pyrites, the species belongs to the genus Iron-pyrites, 

 and the adjective hexahedral signifies that its forms belong 

 to the tessular system, and that cleavage takes place in the 

 direction of the faces of the hexahedron. An image, thus 

 produced of the species by the mere denomination, is in- 

 deed very useful. Yet it cannot serve as a substitute to 

 the character in respect to the process of determining an 

 individual, by the assistance of the Characteristic, nor can 

 it be employed instead of the General Description, for re- 

 presenting the varieties of the species. For commonly it 

 contains only one character, in most cases a very general 

 one, and refers besides to images or representations, which 

 can only be acquired by ocular inspection, and never can 

 receive the precision of a character, nor that exact idea of 



