THEORY OF DEFINITE PROPORTIONS. 163 



as soon as it was supposed that chemical com- 

 pounds had any definite properties. Those who 

 first attempted to establish regular formulae 1 for 

 the constitution of salts, minerals, and other com- 

 pounds, assumed, as the basis of this process, that 

 the elements in different specimens had the same 

 proportion. Wenzel, in 1777, published his Lehre 

 von der Verrcandschaft der Korper ; or, Doctrine 

 of the Affinities of Bodies ; in which he gave many 

 good and accurate analyses. His work, it is said, 

 never grew into general notice. Berthollet, as we 

 have already stated, maintained that chemical com- 

 pounds were not definite ; but this controversy took 

 place at a later period. It ended in the estab- 

 lishment of the doctrine, that there is, for each 

 combination, only one proportion of the elements, 

 or at most only two or three. 



Not only did Wenzel, by his very attempt, pre- 

 sume the first law of chemical composition, the defi- 

 niteness of the proportions, but he was also led, by 

 his results, to the second rule, that they are reci- 

 procal. For he found that when two neutral salts 

 decompose each other, the resulting salts are also 

 neutral. The neutral character of the salts shows 

 that they are definite compounds; and when the 

 two elements of the one salt, P and s, are pre- 

 sented to those of the other, B and n, if P be in 

 such quantity as to combine definitely with n, B 

 will also combine definitely with s. 



1 Thomson, Hist. Chem. vol. ii. p. 279. 



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