46* VIEWS OF BOSCOVICH. 



nor its results be predicted with certainty. In 

 opposition to this simple and rational view of the 

 subject, it was maintained by Boscovich, that 

 the minutest portions of matter consist of mere 

 mathematical points, without extension or solidity, 

 surrounded by alternate immaterial spheres of at- 

 traction, and repulsion, by one of which, the said 

 mathematical points are drawn together, and by 

 the other kept asunder, so as to be prevented 

 from touching. 



We are indebted to the researches of Wenzel, 

 Bergman, and Richter, for the discovery that 

 definite proportions of acids and alkalies are 

 required for mutual saturation ; and that many 

 other chemical combinations take place only in 

 fixed ratios. It was further maintained by Wil- 

 liam Higgins of Dublin, (in a work entitled " A 

 Comparative View of the Phlogistic and Anti- 

 phlogistic Theories," published in 1789,) that all 

 compounds are formed by the union of exceed- 

 ingly minute atoms, which are surrounded by 

 atmospheres of caloric ; and that oxygen unites 

 with nitrogen in proportions which are even mul- 

 tiples of the lowest. But to Dr. John Dalton of 

 Manchester, was reserved the distinguished ho- 

 nour of reducing the atomic theory to a systematic 

 form, in a work entitled " Chemical Philosophy," 

 published in 1808-10, aided by the subsequent 

 analyses of Thomson, Berzelius, Prout, Gay- 

 Lussac, Dulong, and many others. 



The most general law of chemical affinity as 



