16 



Prof. W. A. Miller on Chemical Nomenclature. 



The application of names formed on this principle to the salts 

 of the tribasic acids is comparatively simple, and the atomicity 

 of the metal is readily expressed. For example, — 



3Ca2P0 4 

 H 4 Ca2PO 



I Bone phosphate of lime. 

 j Tricalcic diphosphate. 



Superphosphate of lime. 

 < Tetrahydrocalcic diphos- 

 ( phate. 



Ag 3 AsO 3 

 HCuAsO 5 



j Arsenite of silver. 

 J Triargentic arsenite. 



j Scheele's green. 



) Hydrocupric arsenite. 



The same principle may in most cases easily be applied in the 

 construction of names for the compounds of organic chemistry. 

 Sulphate of methyle, (CH 3 ) 2 SO 4 , for example, becomes dime- 

 thylie sulphate; acetate of ethyl, (C 2 H 5 , C 2 H 3 2 ), ethyllc ace- 

 tate ; and so on. Care must, however, be taken in the construc- 

 tion of names intended to designate the salts of the organic bases, 

 such as sulphate of dimethylia, (C 2 H 7 N) 2 H 2 SO 4 . Dimethylic 

 sulphate would be liable to be confounded with the ether 

 above mentioned ; dimethylia sulphate, or didimethylia sul- 

 phate would distinguish it ; and instead of triethylic phosphate, 

 (C 6 H 15 N) 3 H 3 PO 4 , it should be triethylia phosphate, or tritri- 

 ethylia phosphate. 



In the simpler department of inorganic chemistry there are 

 certain classes of compounds which offer difficulties in any con- 

 sistent system of nomenclature. Among these are the substances 

 which have been termed anhydro -salts, such as certain chromates 

 and iodates. 



Potash forms several such compounds with chromic acid. We 

 have, for instance, 



The normal chromate 

 The so-called bichromate. 

 The trichromate 

 The tetrachromate . 



K 2 Cr O 4 . 



K 2 Cr 2 7 , not KHCrO 4 . 



K 2 Cr 3 O 10 ,notK 2 H 4 3CrO 4 . 



K 2 Cr 4 13 ,notKH 3 2Cr0 4 . 



The formulae given in the second column of the foregoing 

 symbols would in these cases represent salts formed on the nor- 

 mal plan, in which the potassium had partially or completely 

 displaced the hydrogen in one or more atoms of chromic acid. 

 Such compounds, however, have not been obtained in the solid 

 form. In the salts really known, it appears that the normal 

 chromate has been combined with quantities of chromic oxijl, 

 (Cr 3 ), progressively increasing ; and it seems to be necessary in 

 naming them to adopt an arbitrary method. If the normal 

 chromate, (K 2 0, CrO 3 ), be called dipotassic chromate, the others 

 successively may be named — 



