20 NOMENCLATURE OF CHEMISTRY. 



enter into combination with each other, or with the 

 other elementary bodies, they form combinations 

 that are divided into two classes. In one class the 

 substances are ?iotacid, and their names have their 

 termination in ide, as oa:ide of chlorine, oJ^ide of 

 nitrogen, chloride of sulphur, iodide of iron, &c. 

 \VTien these supporters of combustion enter into 

 combination with a body in more than one propor- 

 tion forming oxides, the terminations, ous and ic, 

 are employed. Thus nitrogen, with the smallest 

 proportion of oxygen, forms the 7iitroiis oxide ; 

 and, with a large proportion, it makes the nitric 

 oxide. 



When the metals combine with oxygen in one 

 proportion only, the compounds are called simply 

 oxides of the metals. Formerly the compound of 

 a metal with oxygen was called a caliv, as the calx 

 of tin, now the oxide of tin; and the process of 

 combining a metal with oxygen was called calcina- 

 tiojiy now oaigenation. 



Sometimes oxygen can enter into combination 

 with a metal so as to form oxides in more than one 

 proportion, and then a syllable is prefixed to the 

 term oxide to denote that proportion ; the smallest 

 quantity of oxygen forms the protoj:ide of the me- 

 tal, the second quantity of oxygen makes the 

 deutoaide, and the third, the tritodide ; antl, far- 

 ther, the term peroxide is applied to that oxide of 

 the metal that contains the greatest proportion of 

 oxygen with which it is known to combine. The 

 same syllables are prefixed to chlorides and io- 

 dides. 



An oxide combined with water is called a 

 hydrat. 



When an acid is formed by the union of a simple 

 body with oxygen, it derives its name from that 



