2 1 6 Literary and Philosophical Society. 



fore, read it still more carefully again, and then a third 

 time, but they did not exist. Having written to two 

 eminent historians of science for an explanation, I find 

 that neither had seen the volume, but one of them in- 

 formed me that the mistake had been rectified in a 

 supplement to the " Handworterbuch der Chemie und 

 Physik." ' 



' The reciprocal saturation which results when two salts 

 decompose each other is the discovery, the honour of which 

 has long been given to Wenzel. It is a curious fact that 

 not only does he not see this, but he sees and explains the 

 contrary, as he shows us that in double decomposition 

 something always remains unsaturated, but generally very 

 little remains. One is sorry that, being so near a law, he 

 had not the slightest conception of it. The most im- 

 portant part of his work, as far as our purpose is concerned, 

 seems to me to be contained in the following sentences. 

 The title of the work is " The Doctrine of the Affinity of 

 Bodies." 2 I shall not give the original, although scarce, as 

 the work, from the fact above stated, has lost its great 

 importance. 



' In the preface he says, " At first my only intention was 

 to make for my own use a treatise which should contain 

 the order of the ascertained affinities and the circumstances 

 under which they acted, lest I should not be able to 

 remember them. But it occurred to me that others might 

 find it useful also, if it were more worked out. For this 

 end I endeavoured to explain the cause and the law of 



1 It is by Dr. J. S. C. Schweigger, and has been since published as a 

 pamphlet (Ueber die Stochiometrische Reihen im Sinne Richter^s, &c.), Halle, 



2 Carl Friedrich Wenzel, Lehre von der Vetwandlschaft der Korper t 

 Dresden, 1877. 



