418 M. J. Thomsen's Thermo -chemical Researches. 



and by saying that the division of the base takes place in 



proportion to the number of equivalents of the acids and to their 



energy, 



am 

 r= -jr-j |' 

 am 



m and m! expressing the affinities or energies of the acids for 

 the base. 



This formula would well apply to the reaction of an equivalent 

 of nitric acid on an equivalent of soda, on the supposition that 



— 7= -. But if we try to calculate with the same ratio the other 



reactions, in which various quantities of nitric acid are put into th 

 presence of an equivalent of sulphate of soda, and if we then cal- 

 culate the thermic effects corresponding to these various reactions, 

 we obtain results which in no way accord with those furnished 

 by experiment*. 



Thus Berthollet's theory does not accord with experiment even 

 in the form under which it is usually presented. A formula very 

 different from that of Berthollet has been proposed by M. 

 Guldberg f. 



Let A and B be two bodies which by their reaction produce 

 the bodies C and D (thus, in the present case, A would be sul- 

 phate of soda, B nitric acid, C nitrate of soda, D sulphuric acid) ■ 

 let «, /3, y, and 8 be the number of equivalents of these four 

 bodies respectively which are placed together, and x the num- 

 ber of equivalents of A and of B which mutually decompose one 

 another, so that after the reaction we have 



(«-a?)A+ (0-a?)B+ (7 + <*)C+ (8 + a?)D. 



If we denote by k the energy with which the reaction of A 



upon B takes place, and the inverse reaction of C upon D by-^, 



A. 



we shall have, according to the theory of Guldberg, 



*(«.-ar)08-i).= ^(7+«)(S+*); 

 If the product kk! be expressed by ri 2 , we shall have 



In order to calculate the value of x by means of this formula 

 (that is, the magnitude of the decomposition), we must determine 

 the value of n 2 by means of the reaction in the most simple case, 

 when an equivalent of nitric acid acts on an equivalent of sul- 



* We omit here the details of these calculations and the Tables of com- 

 parison of the results, and only give the conclusions. 



t Etudes sur les affinites chimiques, par G. M. Guldberg et P. Waage. 

 Christiania, 1867. 



