466 Prof. Williamson on Chemical Nomenclature. 



for the present I contemplate ordering a couple of carboys of 

 " sulphuric acid " or " nitric acid " as heretofore, meaning those 

 compounds which in systematic language are designated "hydric 

 sulphate" and "hydric nitrate"; but that when I have to 

 explain to learners the reactions of those hydrogen-salts, I 

 should give them the systematic names which correspond to 

 their composition. The popular and trivial names by which 

 they are known are abbreviations formed so as to point to the 

 essential or characteristic constituent. It is not practicable to 

 send out real sulphuric acid, SO 3 ; but manufacturers and con- 

 sumers know that the value of oil of vitriol is not in the water 

 which it contains, but in the " real acid." In like manner, the 

 common crystals of hydrated sodic carbonate are valuable in 

 proportion to the percentage of soda, Na 2 0, which they contain, 

 and they are not unreasonably named after their characteristic 

 constituent. 



There was, on the part of one or two distinguished members 

 of the Society, a feeling that the retention of the words acid and 

 base in their established signification of "electro-negative oxides " 

 and " electro-positive oxides " might be inconvenient in presence 

 of the fact that chlorine forms with hydrogen a very acid salt, 

 and that some other elements also form acid hydrides. But when 

 it is admitted that H 2 SO 4 is a salt, though of very acid proper- 

 ties, that HNO 3 and H 3 P0 8 are also very acid salts, and that in 

 scientific language they must be designated as salts, it really is 

 not surprising that HC1, HBr, &c. should be salts of considerable 

 acidity, and it is not unnatural to call them salts of hydrogen in 

 systematic nomenclature. The fact that we cannot remove the 

 elements of water from hydric chloride and make CI 2 — 0, whilst 

 we can remove water from hydric sulphate and make SO 4 — 0, is 

 really no reason against classing, side by side, hydrogen-salts 

 with compound radicals such as NO 3 , SO 4 , PO 4 , &c, and those 

 with elementary radicals such as CI, Br, &c. 



Since my suggestions have been published Mr. Poster has 

 published in the Philosophical Magazine a paper " On Chemical 

 Nomenclature, and chiefly on the use of the word Acid." In 

 this paper Mr. Poster expresses assent to the form of names of 

 which I had recommended the systematic adoption ; and he says, 

 " If we regard the salts of hydrogen as constituted like the salts 

 of any other metal, the application to them of the name acid 

 becomes incorrect if it implies any peculiarity of constitution, 

 and superfluous if it does not." Now, as Laurent and Gerhardt 

 did admit and assert that the salts of hydrogen are constituted 

 like the salts of any other- metal, and as Mr. Poster is doubtless 

 perfectly aware that they did so, the above sentence is a distinct 

 condemnation of Gerhardt's proposal of applying the word acid 



