266 On Chemical JVomenclature. 



without its having been possible to eradicate all that has not kept 

 pace with the progress of science. 



Accept the assurance of my perfect esteem, and of the sentiments 

 of sincere friendship with which I have the honor to be, Yours, &tc. 



An Examination, by the AutJwr of this Article, of the Suggestions 

 in the preceding Letter o/Berzelius, and how far the Objections 

 made to his JVomenclature are therein answered. 



So far as my strictures were founded on the alleged difficulty of 

 defining the terms acid, salt and base, in any mode consistent with 

 his classification, they are not met by any Ricts or reasoning in the 

 much esteemed letter of my illustrious correspondent. The imprac- 

 ticability of defining a salt, he does not deny ; and with great candor 

 he admits that, in his definiton of acidity, he has not been consistent. 

 He concedes that it would be preferable to give the syllable, indica- 

 ting the electro-negative ingredient, the precedence, as nothing but 

 unwillingness to innovate, prevented him from pursuing that course. 



He acknowledges that as combustion, in many instances, takes 

 place without the presence of oxygen, the apphcation of the word 

 combustible, should not be confined to bodies which are susceptible 

 of oxydizement. 



My definition of acidity was as follows : — 



" When, of tivo substances capable of combining with each other 

 so as to form a tertium quid,* and having an ingredient common to 

 them both, one prefers the positive the other the negative pole of the 

 Voltaic series, ive must deem the former an acid, and the latter a 

 base. Also all substances having a sour taste, or which redden lit- 

 mus, must be deemed acids, agreeably to usage." This definition I 

 would now amend by leaving out the last sentence, and substituting 

 therefor, the following : Also when any substance is capable of for- 

 ming a tertium quid with any acid or base agreeably to the preceding 

 definition, it must be considered' as an acid in the one case, a base in 

 the other. The definition, thus amended, takes in the organic acids 

 and bases. In the form in which it was at first proposed, it has not 

 been alleged defective by Berzelius ; but he has striven to show an 

 incongruity in the attributes of his double salts, when contrasted with 

 those resulting from the union of some of the acids and bases of his 



* This term tertium quid has been used by chemists, more formerly than of late, 

 to designate a compound resulting from the union of two bodies, but in its proper- 

 ties resembling neither. 



