1824.] Acetic Acid with Peroxide of Copper. 189 



cases which had come under my observation, these salts are so 

 constituted, that a correspondence exists between the multi- 

 ples ot* the base, and the number of atoms of oxygen in the 

 acid ; and that the compounds of acids containing, for exam- 

 ple, 3 atoms of oxygen, (that is, when the oxygen of the acid 

 in the neutral salt is thrice that of the base) take place in totally 

 different multiples from those of acids containing 2 or 4 atoms 

 of oxygen. In the former, the ordinary multiples of the bases 

 are 1^, 3, and 6 ; in the latter, they are 2, and 4 ; so that the 

 resulting compounds are always in conformity with the general 

 rule, that the oxygen of one oxide (that is, either of the acid or 

 base) is a multiple by a whole number of the oxygen of the 

 other. Subsequent experiments have shown, however, that 

 some acids which contain 5 atoms of oxygen, while their cor* 

 responding acidules (acids in ous) contain only 3, do not com- 

 bine with bases in such proportions, that the oxygen of the 

 acid shall always constitute a multiple by a whole number of the 

 oxygen of the base ; but that the oxygen of the base is 1, 2, 4, 

 and 6 fifths of the oxygen of the acid, and 1 , 2, and 4 thirds of 

 the oxygen of the acidule. There are circumstances, indeed, 

 which furnish grounds for a suspicion, that in this class of acid 

 bodies, 2 atoms of the radicle combine with 3 atoms of oxygen 

 to form the acidule, and with 5 to form the acid. And if, in 

 that simple mechanical disposition of atoms which constitutes 

 a compound atom, one atom of the radicle be supposed to 

 occupy the same situation which would have been occupied by 

 an atom of oxygen, had there existed in the acid an atom more 

 of oxygen and an atom less of radicle, we shall be enabled to 

 form an idea of the cause why the acidules combine with bases 

 in the same multiples as if they contained 4 atoms of oxygen, 

 and the acids as if they contained 6 ; in such a manner, that 

 in sub-salts containing a maximum of base, the oxygen of the 

 base is 1^ (1-^-? time) that of the acidule, and li time that 

 of the acid. We have instances of such compounds in the 

 nitrite* and nitrate of lead, with the greatest excess of base. 

 It is obvious that if in the salts produced by these acids, the 

 oxygen of the base were (for example) one fourth or one sixth 

 of the oxygen of the acid, they would constitute exceptions 

 exactly analogous to those which would be formed by the other 

 acids, where, in their salts, the oxygen of one constituent is 

 not an equimultiple by a whole number of the oxygen of the 

 other. 



It may now be asked, do such compounds exist? The above- 

 mentioned rules are purely empirical ; that is, they merely 

 announce that the compounds hitherto examined obev this law ; 

 but we are acquainted with no circumstances which reader a 



* IJyponitritc of Dr. Thomson — Tn 



