CHEMICAL NOMENCLATURE AND NOTATION. 97 



In the class of simple substances are placed all those bodies 

 which are not known to be compound, on the principle that 

 whatever cannot be decomposed or resolved by any process of 

 chemistry into other kinds of matter, is to be considered as 

 simple. They are the only bodies the names of which are at 

 present independent of any rule. An attempt was, indeed, made 

 on the first introduction of a systematic nomenclature, to make 

 the names of several of them significant ; but some confusion 

 in regard to their derivatives was found to be the consequence 

 of this, and many of them being familiar substances, were 

 almost of necessity allowed to retain the names they bear in 

 common language ; such as, sulphur, tin, silver, and the other 

 metals known in the arts. To newly discovered elements, how- 

 ever, such names were applied as were suggested by any striking 

 physical property they possessed, or remarkable circumstance 

 in their history. The names of the newer metals, platinum, 

 potassium, vanadium, etc., have a common termination, which 

 serves to distinguish them as metals. Other classes of elemen- 

 tary bodies, resembling each other in certain particulars, are 

 marked in a similar manner; such as the class comprising 

 carbon, boron and silicon, and that composed of chlorine, iodine, 

 bromine, and fluorine. 



The names of compound bodies are contrived to express their 

 composition, and the class to which they belong, and are 

 founded on a distribution of compounds into three orders, 

 namely : first, compounds of one element with another element, 

 as for instance, oxygen with sulphur in sulphuric acid, or 

 oxygen with sodium in soda, which are called binary compounds. 

 Secondly, combinations of binary compounds with each other, 

 as of sulphuric acid with soda in Glauber's salt, and the salts 

 generally, which are termed ternary compounds. And thirdly, 

 combinations of salts with one another, or double salts such as 

 alum, which are quaternary compounds. 



1 . Of the compounds of the first order, the greater number 

 known to the original framers of the chemical nomenclature, 

 ' contained oxygen as one of their two constituents ; and hence, 

 an exclusive importance was attached to that element. Its 

 compounds with the other elementary bodies, may be divided 

 from their properties into : (a) the class of neutral bodies and 

 bases ; and (b) the class of acids. 



(a) To members of the first class, the generic term oxide was 



H 



