CONJUGATED ACIDS. 185 



tion (accouplement) with the above-named carbo-hydrogens ; the 

 stability is, however, most obvious in those acids in which such 

 easily decomposable bodies as hyposulphurous or hyponitric acid 

 are conjugated ; their salts being altogether dissimilar from those 

 of the non-conjugated acids in their crystalline form, solubility, 

 amount of water, &c. 



In combinations of this kind the electro-chemical polarity is 

 entirely lost ; the older dualistic views of chemistry here altogether 

 fail us; we must therefore here assume another ground of chemical 

 attraction than that of opposite polarity, and this view is confirmed 

 by the circumstance that these compounds cannot be decomposed 

 according to our ordinary chemical principles, that is to say, by 

 simple or double elective affinity. They also no more admit of being 

 decomposed into their proximate constituents, that is to say, into 

 the acid and the adjunct, than of being directly formed from them. 

 Most of the conjugated acids are only formed when the adjunct in 

 its nascent state comes in contact with the acid ; and conversely it 

 is only very few of them that can be decomposed into the acid and 

 the adjunct, and even in this case the adjunct invariably assimi- 

 lates water, and it is impossible to determine with certainty whe- 

 ther the isolated hydrated body in its anhydrous condition actually 

 constituted the adjunct, or whether the latter body was represented 

 by some other group of atoms. This favourable condition, how- 

 ever, very rarely aids us ; for generally, in our attempts to sepa- 

 rate the adjunct from the acid, the former becomes so decomposed 

 that we can arrive at no conclusion regarding its nature : and this 

 is the reason why chemists, when they enter into the general con- 

 sideration of the laws of conjugated acids have to trust more or less 

 to hypotheses ; and it would scarcely be in accordance with our 

 views to follow their track. We shall,, however, be compelled to 

 devote some attention to these hypotheses when we treat of the 

 acids of this class, pertaining to zoo-chemistry ; and we will here 

 only remark that we will subsequently treat of those combinations 

 of organic acids with organic oxides in which all acidity has disap- 

 peared, and which have been named by Berzelius haloid salts, 

 whilst other chemists of the present day have included them in the 

 category of conjugated compounds. 



Most of the known conjugated acids are formed by the action 

 of sulphuric or nitric acid on organic substances. In the following 

 group, picric acid is the only one we will consider in any detail, 

 partly by way of general illustration, and partly because it occurs 

 more frequently than the others as a product of the decomposition 



