CHEMICAL SUBSTANCES BY MEANS OF GENERIC RADICALS. 333 



cate it by a single symbol, and I shall use the Greek letter H for this purpose.* 

 The relation of 5 to CN, or of the acid to the nitrile, is seen not only in the mono- 

 basic acids (monocarbonsauren), but also in the di- and tri-basic acids (di- and tri- 

 carbonsauren), so that these contain the radical 3, two and three times respectively. 

 The investigation sketched above also shows that COH and CH 2 (HO), are 

 the radicals of the aldehydes and the "true" alcohols. Pursuing this method 

 further, we arrive at a system of classification for the various groups of pseudo- 

 alcohols, the number of which has recently increased so much. One of these 

 groups is formed by the hydrogenation of the acetones. The acetones have the 

 general- formula COR 2 (in which R 2 may represent either two atoms of the same 



0-0=0 

 or of two different radicals) ; taking the graphic formula, we have Y 



(-©-© being the generic radical), by the addition of H 2 , we get Y the 



0-0-0 



© 

 reaction being similar to that by which the aldehydes are converted into true alco- 

 hols, one of the two pairs of equivalents by which the atom is united to the C, 

 being separated, and hydrogen added to each of the equivalents (one of and one of 

 C), thus rendered free. The generic radical here is obviously {(CTI(HO)} ", and the 

 subgenera and individual substances are determined by the radicals saturating 

 the two free equivalents of this generic radical. This genus, besides the universal 

 character of the alcohol family (the formation of ethers) has the property of form- 

 ing aldehydic bodies (acetones) by the loss of two atoms of H, {CH(HO)}" be- 

 coming (CO)"; and in that subgenus which contains the radical {CH 2 (HO)} / (or 

 in which one of the R's is H), this aldehydic body is a true aldehyde, capable of 

 forming an acid by further oxidation. When none of the equivalents of the carbon 

 atom in the generic radical are directly saturated with H, the alcohol is incapable 

 of producing an aldehyde or acetone; and, in this case, we have the characteristic 

 radical reduced to {C(HO)} /// , as in Butlerow's trimethyl alcohol. We thus see 

 that the most generalform of alcohol is C(HO)R 3 (where R 3 represents one triatomic, 

 or one diatomic and one monatomic, or three monatomic radicals) ; and the genera, 

 sub-genera, and individuals of this family are determined by the nature of the 

 radical or radicals, combined with the family radical {C(HO)| /// . For con- 

 venience let us, in the meantime, represent this radical by the symbol 3>'". 

 The different subdivisions of the family will then be R'"$, R'lt^, and R' 3 $ If 



* I had proposed to express the radical (COHO)' by the symbol H, before I was aware that 

 Butlerow had already used the symbol A to represent the same radical. While fully acknowledging 

 the priority of Butlerow's recognition of this radical, I prefer to retain the symbol H. Bv using 

 such of the Greek capitals as differ from the Roman in form, to represent generic radicals, we avoid 

 the danger of confounding them with elementary atoms. 



