Wenzel. 2 1 3 



Morveau's chemical laws, which he himself thinks can 

 scarcely be called laws, and as they are not essential to 

 our purpose, we shall not repeat them here. 



Dr. Cullen seems to have been the first who gave 

 diagrams of double or elective attraction. These do not 

 appear to have been published, but they were used by 

 Dr. Black in his lectures, and the publication has been left 

 for Bergman, to whom we readily grant equal originality 

 and more energy in giving the idea to the world. He 

 could not, however, explain how neutral salts could receive 

 an excess of acid ; in other words, he had no idea of 

 addition by equivalent, and therefore could not compre- 

 hend an atomic theory such as Dalton's. 



To Wenzel has often been given the honour of dis- 

 covering reciprocal proportion, but we must conclude that 

 he failed in his attempts to explain the mutual decompo- 

 sition of salts, and considers that it is not complete. He 

 seeks to explain affinity by the time of action, and says : 

 The affinity of bodies with a comino7i solvent is in the inverse 

 ratio of the time taken to dissolve. Of this theory one 

 may quote what is elsewhere said, ' He has made a theory 

 of affinity and attempted to represent the force by a 

 number. To attempt to give the numerical or dynamical 

 ratio of every body to each other was an object of the very 

 highest kind, and we must look on him as one of those 

 less fortunate men who, when search was required in every 

 direction, has had the wrong one assigned to him. He 

 searched in the direction of time, and obtained a manifest 

 fallacy; as bodies are constructed abstractedly he might 

 be correct, but his theory cannot be introduced into 

 science at present, and in the way he introduced it it is 

 entirely a mistake. But he has done great service in early 



