T. S. Hunt on Chemical Classifications. 405 



its free state it is a combination of two atoms, and is really CI 2 ; 

 the same view extends to the metals. 



It has been shown that the hypothesis of M. Gerhardt, which 



supposes that in ethers and amids, alcohol and ammonia minus 



^ H 2 , replace an equivalent of oxygen, is objectionable because it 



does not account for the changes in the basic relations of the 

 acids, and leaves unexplained the reason of his law of S«X — 1. 







I 



We are thus led to recognize the view of Liebig, apart from his 

 ideas of dualism, find his theory of compound radicals, as the 

 one fundamentally true, and it remains to give it a general ex- 

 pression which shall include all the reactions of the class which 

 we are now reviewing. This, we shall endeavor to show, may 

 be accomplished by an application of the great principles which 

 M. Gerhardt has defined in his Precis, although still misled by 

 the electro-chemical philosophy, he seems to have erred in their 

 application. 



The class of compounds which we are considering in the pres- 

 ent essay, may be viewed as products formed by an apomorphosis 



which generally consists in the separation of the elements of 



water ; and this class will be found to include the greater part of 

 all chemical compounds. M. Gerhardt observes that, "of 1,000 

 reactions taken at hazard, 990 of them will consist in the elim- 

 ination of some substance from the organic matters, and this 

 something is always water, hydrochloric acid, or some other min- 

 eral substance with a composition equally simple.' r * 



In these reactions the saline capacity of one of the bodies is 

 always wholly or in part neutralized ; in the ethers by the re- 

 placement of the hydrogen by C 2 H 5 , and in the amids by the 

 substitution of NH 3 — O for that element. These, as M. Gerhardt 

 remarks, are related to the ammoniacal salts, in which Nil ( repla- 

 ces H, as anhydrids are to acids ; the process may proceed still 

 farther under the influence of heat or a dehydrating agent, and the 

 monobasic salt eliminate a second equivalent of water, forming a 

 nitrile. This is due to a farther reaction between the acid and the 

 replacing elements, resulting like the previous one, in the sepa- 

 ration of II, O, and a more intimate union than before, and is 

 analogous to the change effected by heat upon tartar emetic and 

 similar salts. These compounds, like simple anhydrids, must all 

 be regarded as pertaining to the acid from which they are derived, 

 and we are hence led to the enunciation of the following princi- 

 ple which applies to all coupled bodies whatsoever. 



In all compounds produced by a reaction which results in the 

 elimination of one or more equivalents of water or hydrochloric 

 acid, (or any body referable to the type H 2 O or H %f ) the parent 

 body is that which loses saline hydrogen. 



(To be continued.) 



* Precis, torn, ii, p. 495. 



