Evolution of the Doctrine of Affinity. 505 



did not seem to farther his great work ; while he offered a 

 most strenuous opposition to all those which he conceived 

 would bring disorder into his classification. He even disputed 

 for half a generation Davy's discovery of the elementary cha- 

 racter of chlorine, simply because he could not reconcile it 

 with his views. 



But the discovery in the earlier part of this century of the 

 relations between the electrical and the chemical behaviour of 

 elements and compounds appeared to him to afford great 

 assistance in the development of his system ; and hence he 

 based his whole classification on positive and negative cha- 

 racters of substances, manifested electrically ; and for a time, 

 at least, he identified affinity with electrical attraction. 



Alongside of this electrochemical hypothesis, every other 

 doctrine of affinity appeared superfluous ; and, as a con- 

 sequence, Berthollet's teachings were forgotten,, although they 

 were by no means contrary to the newer views. The electro- 

 chemical theory of Berzelius, however, was never fully deve- 

 loped in detail. Even though he laid great stress on it, though 

 he often referred to it, and insisted on its fundamental nature, 

 yet there is not to be found in any of his numerous memoirs 

 in which it is mentioned, nor in his Jaliresbericht, in which 

 he criticised the electrochemical theories of other investi- 

 gators, nor even in any one of the numerous editions of his 

 Textbook, an attempt at a complete exposition of his theory. 

 In actual fact, the electrochemical theory never rose above 

 the general conception that the chemical and electrical 

 behaviour of bodies are closely connected. The explanation 

 was only an apparent one : it consisted only in ascribing to 

 electrical causes observed chemical facts. An attempt to 

 measure affinities on such a basis failed, owing either to the 

 lack of experimental data or to its being contradicted by 

 them. 



Erroneous deductions from his theory misled Berzelius, 

 not only in causing him to disbelieve Davy's proof of 

 the elementary nature of chlorine, but also in leading him 

 vigorously and persistently to dispute Faraday's electrolytic 

 law. While he withdrew from his opposition to Davy after 

 a sixteen years' struggle (1826), when the analogy between 

 hydrogen chloride and hydrogen sulphide had been fully 

 recognized, he continued to reject until his death that most 

 important of all electrochemical discoveries, Faraday^s law. 

 These two facts serve sufficiently to show that Berzelius's 

 theory was unable to yield a thorough explanation of affinity. 

 That in spite of such weak points, sufficiently evident today, 

 a man of Berzelius's great power could hold fast to them 



Phil. Mag. S. 5. Vol. 23. No. 145. June 1887. 2 M 



