SULPHURIC ACID. S29 



Sulphuric acid appears by the first column to be capable of 

 combining with a base in three multiple proportions, and so 

 also does chromic and probably also manganic and selenic acids 

 which are isomorphous with sulphuric acid, while nitric acid 

 and carbonic acid, so far as is known, combine with bases only 

 in one proportion. lodic acid, it will afterwards be found, cor- 

 responds with sulphuric acid in this respect, there being an 

 anhydrous iodate, biniodate and teriodate of soda (Mr. Penny). 

 The composition of such salts is not easily reconciled with the 

 doctrine of the constitutional neutrality of salts, or with the 

 salt-radical theory, as has already been remarked (page 170). In 

 the second column these sulphates are represented in a different 

 manner, suggested by the relation in composition to each other 

 of certain organic acids, particularly of the class including cyanic, 

 fulminic and cyan uric acids, in the second and third of which, 

 respectively, the atom of cyanogen is doubled and trebled.* A 

 similar duplication and triplication of the atom in compounds, 

 seems to be not an uncommon cause of isomerism, as in the 

 hydrocarburets (page 156, and table of densities, page 134). 

 The acid itself is supposed in the second column to be different 

 in these three salts, namely SO 3 , S 2 O 6 , S 3 O 9 , and the salts 

 cease to be anomalous, being all represented as neutral salts, 

 containing one atom of acid, to one of base. In the third 

 column, the same view of the constitution of these sulphates is 

 accommodated to the salt- radical theory. 



These duplicated and triplicated sulphuric acids are supposed 

 above, to form each a monobasic class of sulphates ; but if, 

 moreover, it be assumed that one of them, the duplicated sul- 

 phuric acid S 2 O 6 , with the corresponding chromic acid Cr 2 O 6 , 

 is also capable of forming a bibasic class of salts, then some 

 other salts of the same class will be brought more in accordance 

 with the general views entertained respecting salts, than those 

 salts at present are, as their constitution is generally represented. 

 The salts named will be represented as follows : 



f I may take this opportunity to rectify the statement made respecting 

 these acids at page 168. Liebig in his recent memoir on the organic acids 

 has represented cyanic acid as monobasic, MO + CN,O ; fulminic as bibasic, 

 2MO + C 2 N 4 O 3 ; and cyanuric as tribasic, 3MO + C S N 8 O 8 , and not these acids 

 as all equally tribasic. An. de Ch. et de Ph. t. 63, p. 5. 



