Prof. Williamson on Chemical Nomenclature. 469 



must be represented and named like other salts ; hydric nitrate, 

 or hydric phosphate like potassic nitrate or potassic phosphate, 

 and potassic hydrate or calcic hydrate like potassic nitrate or 

 calcic nitrate ; and Gerhardt's attempt to apply to bodies of the 

 first class the name acid is, in the words of Mr. Foster, "incorrect 

 if it implies any peculiarity of constitution [different from other 

 salts], and superfluous if it does not." Mr. Foster might, how- 

 ever, as above remarked, have added that Gerhardt's definition 

 of the word acid is simply in itself devoid of meaning. He 

 quotes it thus : Acids are "salts whose base [the italics are mine] 

 is wholly composed of hydrogen." A person ignorant of the 

 meaning of the words acid and base could surely not ascertain 

 from his inner consciousness which is the acid and which the 

 basic constituent in any of the following compounds, KOH, 

 HNO 3 , Ba0 2 H 2 , S0 4 H 2 ; and Gerhardt's pretended definition 

 would afford him no aid in ascertaining which of these compounds 

 are to be called acids, which bases. One is almost tempted to 

 suspect Mr. Foster of bitter irony when he calls this definition 

 " strictly scientific and logical." Although different in form, it is 

 not one bit more reasonable than the Munchausen (or Irish ?) 

 feat of ascending to the moon by the aid of a mile-long chain, 

 the traveller first fastening his chain by one end at a point one 

 mile up, then climbing up by the chain to that point, and so on. 

 But I am sorry to say that Gerhardt's disciple is even in a worse 

 plight than the aeronaut, he is so unfortunately circumstanced 

 that even if his chain were fastened one mile up, he could not 

 climb up it. For if, as a preliminary to the understanding of 

 Gerhardt's dictum, we are told how to find out which is the acid 

 and which the basic constituent of a given compound, we find 

 that this preliminary information is inconsistent with Gerhardt's 

 dictum, and prevents our making any use of it. By the aid of 

 a battery anybody could find out which are electro-negative, 

 which the electro-positive oxides derivable from the above com- 

 pounds; but Gerhardt would then reject the result as inappli- 

 cable to his purpose. 



It has always seemed to me that the most plausible objection 

 to the use of the terms acid and base in the sense of electro-nega- 

 tive oxide and electro-positive oxide was the fact that some acids, 

 such as SO 3 , P 2 5 , SiO 2 , &c, may be put in contact with bases 

 such as BaO, K 2 0, &c. without manifesting any strong tendency 

 to combine with them ; and observations of this kind led some 

 chemists to say that, in their chemical properties, these so-called 

 acids do not behave like acids, and that it is therefore reasonable 

 to deprive them of the name acid. Now the fact is that these 

 acids always do combine with bases when brought in contact 

 with them in the fluid state, and they combine with more force 



