98 CHEMICAL NOMENCLATURE AND NOTATION. 



applied^ the first syllable of oxygen, with a termination indica- 

 tive of combination ; to which the name of the other element 

 was joined to express the specific compound. Thus a compound 

 of oxygen and hydrogen is oxide of hydrogen ; of oxygen and 

 potassium,, oxide of potassium ; of which compounds the first 

 or water, is an instance of a neutral oxide ; and the second or 

 potash, of a base or alkaline oxide. But the same elementary 

 body often combines with oxygen in more than one proportion, 

 forming two or more oxides ; to distinguish which the Greek 

 prefix proto (?rpwroc first) is applied to the oxide containing the 

 least proportion of oxygen; deuto (&vrc/>oe, second) to the oxide 

 containing more oxygen than the protoxide ; and trito (rpiTog, 

 third) to the oxide containing still more oxygen than the deut- 

 oxide ; which last oxide if it contains the largest proportion of 

 oxygen, with which the element can unite to form an oxide, 

 is more commonly named the peroxide, from per the Latin 

 particle of intensity. Thus the three compounds of the metal 

 manganese and oxygen are distinguished as follows : 



Composition 

 Names Manganese Oxygen 



Protoxide of manganese. . 100 29.81 



Deutoxide of manganese. . 100 43.36* 



Peroxide of manganese. . 100 57-82 



As the prefix per implies simply the highest degree of oxidation, 

 it may be applied to the second oxide where there are only two, 

 as in the oxides of iron, the second oxide of which is called, 

 indifferently, the deutoxide or peroxide of iron. M. Thenard, 

 in the last edition of his Traite de Chimie, avoids the use of the 

 term deutoxide, and confines the application of peroxide to 

 such of these oxides as, like the peroxide of manganese, do not 

 combine with acids. He applies the names sesquioxide and 

 binoxide to oxides, which are capable of combining with acids, 

 and contain respectively, once and a half and twice as much 

 oxygen as the protoxides of the same metal. He has thus the 

 protoxide, sesquioxide and peroxide of manganese, the protoxide 

 and sesquioxide of iron, the protoxide and binoxide of tin, etc. 

 The sesquioxides of iron and manganese of Thenard, are also 

 named tr it oxides by some French chemists, as to double the 

 proportion of metal in the protoxides, they possess three times 

 as much oxygen. Certain inferior oxides, which do not com- 

 bine with acids are called suboxides ; such as the suboxide of 



