4 HISTORICAL INTRODUCTION. 



to analyze various chemical substances, especially 

 by Bergman, who had acquired so great a repu- 

 tation, that his opinions carried with them a 

 high degree of authority, and his analyses were 

 for some time considered as models of accuracy 

 a character* to which they are by no means 

 entitled. 



J. ]? or the first accurate set of experiments 



covers the 



relative on the composition of salts, we are indebted to 

 adds and Wenzel, a German chemist, who published in 

 1777> a small work entitled, Lehre von der Ver- 

 wandschaft der Korper, or Theory of the Affinities 

 of Bodies. He had been struck with a phenome- 

 non which had already drawn some attention 

 from chemists ; namely, that two neutral salts 

 preserve their neutrality after mutually decom- 

 posing each other. Wenzel proved by a long 

 series of very accurate analyses, that all the al- 

 kalies and earths bear the same ratio to all the 

 acids. For example : if a given quantity of sul- 

 phuric acid be saturated by 



9-75 barytes, 

 6-5 strontian, 

 6 potash, 

 4 soda, 

 3-5 lime, 

 2-5 magnesia, 



the respective quantities of these earths and al- 

 kalies, which saturate a given quantity of each 

 of the other acids, will be to each other as the 



