TERMINOLOGY AND NOMENCLATURE. 257 



and that of chemistry, which we owe to the illustrious group 

 of chemists who flourished in France towards the close of the 

 eighteenth century. In these two departments, not only has 

 every known species, or lowest Kind, a name assigned to it, 

 but when new lowest Kinds are discovered, names are at once 

 given to them on an uniform principle. In other sciences the 

 nomenclature is not at present constructed on any system, 

 either because the species to be named are not numerous 

 enough to require one, (as in geometry for example,) or because 

 no one has yet suggested a suitable principle for such a system, 

 as in mineralogy ; in which the want of a scientifically con- 

 structed nomenclature is now the principal cause which retards 

 the progress of the science. 



5. A word which carries on its face that it belongs to a 

 nomenclature, seems at first sight to differ from other concrete 

 general names in this that its meaning does not reside in its 

 connotation, in the attributes implied in it, but in its denota- 

 tion, that is, in the particular group of things which it is 

 appointed to designate ; and cannot, therefore, be unfolded by 

 means of a definition, but must be made known in another 

 way. This opinion, however, appears to me erroneous. 

 Words belonging to a nomenclature differ, I conceive, from 

 other words mainly in this, that besides the ordinary connota- 

 tion, they have a peculiar one of their own : besides connoting 

 certain attributes, they also connote that those attributes are 

 distinctive of a Kind. The term " peroxide of iron," for 

 example, belonging by its form to the systematic nomencla- 

 ture of chemistry, bears on its face that it is the name of a 

 peculiar Kind of substance. It moreover connotes, like the 

 name of any other class, some portion of the properties common 

 to the class ; in this instance the property of being a com- 

 pound of iron and the largest dose of oxygen with which iron 

 will combine. These two things, the fact of being such a 

 compound, and the fact of being a Kind, constitute the conno- 

 tation of the name peroxide of iron. When we say of the sub- 

 stance before us, that it is the peroxide of iron, we thereby 

 assert, first, that it is a compound of iron and a maximum of 



VOL. II. 17 



