LECTURE XII. 



MIXED TYPES RELATION BETWEEN KOLBE'S VIEWS AND THE COPUL^E 

 OF BERZELIUS RADICALS CONTAINING METALS CONJUGATED 

 RADICALS KOLBE AND FRANKLAND AND THE VIEWS REGARDING 

 TYPES POLYBASICITY AS AN EVIDENCE FOR THE ACCURACY OF 

 THE NEW ATOMIC WEIGHTS DISCOVERY OF THE POLYATOMIC 

 ALCOHOLS AND AMMONIAS. 



I AGAIN desire to direct attention to the theory of types in the 

 form in which it had been established by Gerhardt. The latter 

 had divided organic substances into natural families, if I may 

 so express myself, represented by the four types, water, hydro- 

 chloric acid, ammonia, and hydrogen, which were also called 

 by him types of double decomposition. In this connection it 

 must be pointed out that Gerhardt assumes the existence of 

 conjugated radicals, so as to be able to include substitution 

 products also in the types, and " to connect with one another 

 several systems of double decomposition of a substance." 1 For 

 this purpose he employed, in part at least, the same mode of 

 regarding substances as Kolbe, an exposition of which I have 

 still to give. 



It must now be pointed out that the conjugated compounds 

 are no longer considered in the sense previously stated by 

 Gerhardt ; and not only has the name of the " corps copules " 

 been changed into " corps conjuges," but the signification of 

 the thing itself has been altered. The law of basicity, already 

 discussed in detail, no longer finds any application ; ' 2 mono- 

 basic acids can now give rise to conjugated compounds by 

 interacting with neutral substances ; and to this class of con- 

 jugated compounds there are now reckoned all the substances 

 produced by substitution (acids especially), and consequently 



1 Gerhardt, Traite. 4, 604. 2 Compare p. 183. 



