30 CHEMISTRY. 



The termination of names of compound bodies is directed chiefly 

 by analogy ; thus the non-acid compounds of chlorine, iodine, bromine 

 and fluorine, from the analogy of these bodies with oxygen, are 

 named chlorides, bromides, iodides, &c. The compounds of the in- 

 fliammables terminate generally in uret, as carburet, sulphiiret, 

 iphosTphuret, &c. 



Different oxides of the same metal are distinguished by the 

 numerals prefixed. The oxide containing a single equivalent of the 

 metal and oxygen, is named protoxide ; that containing the greatest 

 amount of oxygen, the peroxide ; the intermediate oxides are ex- 

 pressed by Latin numerals, as the deutoxide or binoxide, teroxide 

 or tritoxide, &c. ; the Greeks numerals, dis, tris, &c., prefixed, 

 denote oxides containing one equivalent of oxygen with two, three, 

 or more equivalents of the metal ; thus, the dioxide of copper. A 

 suboxide signifies an oxide containing less oxygen than a protoxide. 



The same system is also extended to salts, where there is more 

 than one formed by an acid with the same base. When the salt is 

 neutral it is simply named according to the nature of the acid, as 

 sulphate or nitrite ; if it contains two equivalents of the acid, it is 

 named a 6^sulphate, or a &^carbonate, &c. If it contains two equi- 

 valents of the base, it is named a d'zsulphate, &c. The term sesqui, 

 (one and a half,) is used to indicate the relation of 1 to 1 J, or 2 to 

 3, as in the sesquioxide of iron, a compound consisting of two eq. 

 of iron and three of oxygen. 



The generic part of the name of a compound is usually formed 

 from that ingredient which is the most electro-negative ; thus in 

 compounds formed between oxygen, chlorine, iodine and sulphur, 

 we say oxide of chlorine, chloride of iodine, iodide of sulphur ; and 

 not chloride of oxygen, iodide of chlorine, or sulphuret of iodine'. 



It is often, however, very difficult to apply appropriate names to 

 the highly complex bodies of the organic world ; in which cases 

 more particularly, the use of chemical signs or symbols becomes 

 very advantageous, as will be briefly shown. 



Every elementary substance is designated by the first letter of its 

 Latin name, in capital, or by the first letter conjoined with a second 

 small one most characteristic, since the names of many bodies begin 

 alike ; thus. Aluminium, Al. ; Arsenic, As. ; Bromine, Br. ; Boron, 

 B. ; Barium, Ba. ; Carbon, C. ; Chlorine, CI. ; Hydrogen, H. ; 

 Iodine, I. ; Iron (feiTum), Fe. ; &c. It is always understood that these 

 symbols express one equivalent of the substance. 



Combination between bodies is expressed by a mere juxtaposition 

 of the symbols, or sometimes by interposing the sign + : thus 

 water is expressed by HO, or H-f-0 ; hydrochloric acid, by HCl, or 

 H-fCl ; protoxide of iron, by FeO, or Fe + O. 



When more than one equivalent is intended the number is either 

 prefixed to the symbol, or else placed afler it : thus, sulphuric acid, 



