452 SCIENTIFIC THOUGHT. 



these other views of nature, which up to the middle of 

 the century had grown up independently. 



The next chapter will accordingly deal with the 

 kinetic view of nature. 



At the time when the atomic theory was firmly estab- 

 lished and defined, the great founders of chemical science 

 were well aware that the investigation and measurement 

 of chemical forces, of what was termed affinity, was just 

 as important a problem as the fixing of the combining 

 weights and the formula^ of chemical compounds. 



Accordingly we find men like Bergmann, Berthollet, 



Davy, Berzelius, and Faraday all propounding or suggest- 



50. ing theories of chemical affinity, some of which, like the 



Theories of _ . . 



'^ftfnit'''^^ electro-chemical theory, remained long in use. The diffi- 

 culty, however, which was experienced in defining, and 

 still more in measuring, chemical affinity, and the absence 

 of a general system for the computation and calculation 

 of all physical quantities, retarded the progress of this 

 line of research compared with the study of the weights 

 or proportions of mass which existed in chemical processes, 

 and which were more easily ascertained by means of the 

 balance, and made intelligible by the atomic theory. 



The tendency of chemical reasoning during the first 

 half of the century lay therefore in the direction of a 

 one-sided development of the knowledge of matter, its 

 definite constituents and infinite compounds, rather than 

 in a study of that equally important but more svibtle 

 quantity, now called energy, which appears or disappears, 

 but is never created or destroyed in physical or chemical 

 processes. 



A clear recognition of this fundamental doctrine nay, 



