LECTURE IX.] HISTORY OF CHEMISTRY. 169 



the action of electrical forces ; but what he declares to be 

 erroneous, and irreconcilable with the phenomena of substi- 

 tution, is the assumption that the electrical state of the atoms 

 is unchanging. 



The fatal moment had now arrived ; it was a question of 

 defending dualism, and the electro-chemical theory, which was 

 in the fullest agreement with it, and which had prevailed, 

 almost unattacked, for nearly twenty years, against the views 

 that had been stated in opposition to it. Ways and means 

 had to be devised whereby the newly-discovered facts with 

 respect to substitution could be brought into harmony with the 

 electro-chemical ideas. 



Before the storm actually broke, Berzelius had perceived 

 the threatening clouds gathering about him, and had taken 

 his precautions. As soon as Laurent had assumed, in his first 

 papers, that the hydrogen of the nucleus (or fundamental 

 radical) could be replaced by chlorine, Berzelius, quite cor- 

 rectly perceiving the danger to his theories which such views 

 might possess, repudiated energetically the statements of 

 Laurent. 47 The entrance of electro-negative elements into 

 radicals is put aside as an untenable hypothesis ; and even the 

 oxygen radicals, which he had greeted with so much pleasure 

 a few years previously, are discarded. This assumption is, 

 according to Berzelius, " of the same kind as that which would 

 regard sulphurous acid as the radical of sulphuric acid, and 

 manganese peroxide as the radical of manganic acid. An 

 oxide cannot be a radical. The conception of the word radical 

 is such that it represents the substance which, in an oxide, is 

 combined with oxygen." 



Berzelius now only recognises radicals which contain carbon 

 and nitrogen, carbon and hydrogen, or carbon, nitrogen, and 

 hydrogen. 



Sulphur "cannot enter into the composition of a radical 

 any more than oxygen can." " The ternary radicals " must 

 therefore be regarded " either as compounds of a binary sub- 



47 Berzelius, Jahresbericht 1839, 358. 



