Manchester Meuioirs, Vol. liv. (1910), No. 7. 3 



more elaborate, were now seen to be obsolete, for they 

 had been drawn up in ignorance of the effects of mass- 

 action. Torbern Bergman, in particular, had prepared 

 mere numerous and more elaborate tables than any that 

 had previously appeared, and had also endeavoured to 

 extend the theory of affinity to the reactions of acids, 

 bases, and salts. Berthollet showed that affinity had 

 nothing to do with these reactions, which are governed 

 by mechanical considerations, such as the insolubility 

 and volatility of a substance. Von Meyer, in his "History 

 of Chemistry," advances the opinion that Berthollet's 

 teaching was neglected. " His principles were held to be 



totally erroneous It was thus that Bergman's 



doctrine, although based upon wrong assumptions, and 

 therefore leading its author to false conclusions, kept for 

 so long a time the upper hand." ^ Ladenburg is much 

 nearer the mark when he remarks that " tables of affinity 

 disappear soon after the appearance of Berthollet's 

 ' Statique Chimique.'"^ The truth is that Berthollet's 

 ideas supplanted Bergman's with an ease almost un- 

 paralleled in the history of science. Karsten remarked 

 in 1803 that not a trace was to be found of our previous 

 ideas on affinity,' and as early as 1801, Fischer, who 

 translated Berthollet's "Recherches" into German, declared 

 that the new view of chemical phenomena was so con- 

 vincing that it was impossible to uphold the old theory.'' 

 ^ " Hist, of Chem.," Eng. trans., p. 551, 1906. 



* " Hist, of Chem.," Eng. trans., p. 41, 1900. 



* Allg.J. Cheiii., (Scherer), vol. 10, p. 137. 



" Allg.J. Chem., (Scherer), vol. 7. pp- 507, 517. It is difficult here 

 to avoid overstating the truth, one way or the other. Of course the dis- 

 appearance of tables of affinity from the text-books of chemistry, in conse- 

 quence of Berthollefs teaching, was not absolute. Objections to his teaching 

 were urged by Pfaff ia 18 1 1 (see Appendi,\) and by Davy, " Elements of 

 Chemical Philosophy," pp. II7— 124, 1812 (see also Henry, "Elements of 

 Experimental Chemistry," vol. I, pp. 66 — 67, 1829). Nevertheless, Ber- 

 thollet's doctrine of chemical affinity, in its main features, was never seriously 

 challenged. 



