NOMENCLATURE. 83 



either with one another, with a metal, or with a metallic 

 oxide. Sulphuret and carburet of iron, for example, signify 

 compounds of sulphur and carbon with iron. The different 

 oxides or sulphurets of the same substance were distinguished 

 from one another by some epithet which was commonly 

 derived from the colour of the compound, such as the black 

 and red oxides of iron, and the black and red sulphurets of 

 mercury. Though this practice is still continued occasion- 

 ally, it is now more customary to distinguish different degrees 

 of oxidation by derivatives from the Greek. Protoxide sig- 

 nifies the first degree of oxidation, deutoxide the second, trit- 

 oxide, the third, and peroxide the highest. The sulphurets, 

 carburets, &c., of the same substances, are designated in a 

 similar way. The combinations of acids with alkalis, earths, 

 or metallic oxi4es, were termed salts, the names of which 

 were so contrived as to indicate the substances contained in 

 them. If the acidified substance contains a maximum of 

 oxygen, the name of the salt terminates in ate ; if a mini- 

 mum, the termination ite is employed. Thus, sulphate, 

 phosphate, and arseniafe of potash, are salts of sulphuric, 

 phosphoric, and arsemc acids ; while the terms sulphate, 

 phosphate, and arsemfe of potash, denote combinations of 

 that alkali with sulphurous, phosphorous, and arseniows acids. 

 The advantages of a nomenclature, which disposes the dif- 

 ferent parts of a science in so systematic an order, and gives 

 such powerful assistance to the memory, are incalculable. 

 The principle has been acknowledged in all countries where 

 chemical science is cultivated, and its minutest details have 

 been adopted in Great Britain. It must, however, be 

 admitted, that, in some respects, this nomenclature is defec- 

 tive. The erroneous idea of oxygen being the general 

 acidifying principle, has exercised an injurious influence over 

 the whole structure. It would have been convenient, also, 

 to have had a different name for hydrogen. But it is now 

 too late to attempt a change ; for the confusion attending 

 such an innovation, would more than counterbalance its 

 advantages. The original nomenclature has, therefore, been 

 preserved, and such additions have been made to it as the 

 progress of the science rendered necessary. The most 

 essential improvement has been suggested by the discovery 

 of the laws of chemical combination. The different salts 



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