266 On Chemical Nomenclature. 
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, &e. 
An Examination, by the Author of this Article, of the Suggestions 
in the preceding Letter of Berzexius, and how far the Oljections 
made to his Nomenclature 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 facts or reasoning in the 
much esteemed letter of my illustrious correspondent. ‘The imprac- 
ticability of defining a salt, he ddes 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- 
lng the electro-negative ingredient, the precedence, as nothing but 
unwillingness to innovate, prevented him from pursuing that course. 
at as combustion, in many instances, takes 
place without the presence of oxygen, the application of the word 
‘combustible, should not be confined to bodies which are susceptible 
of oxydizement. 
My definition of acidity was as follows :— 
“When, of two substances capable of tombintag 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, we 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 1 
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 
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 
ce This term tertiwm quid has been used by chemists, more formerly than of late, 
o designate a compound resulting from the union of two bodies, but in its propel 
es resembling neither. 
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