390 SCIENTIFIC THOUGHT. 



or elements. A very large field of research all on the 

 lines pointed out by the new school was opened out. But 

 the age for a further application of mathematical reason- 

 ing came much more slowjy in chemistry than in physical 

 science. 



The latter had at least one great department, in which 

 a small number of factors, all admitting of mathematical 

 accuracy those of distance, mass, and motion sufficed 

 to explain the phenomena, at least if viewed from a great 

 distance. This science is the physics of the heavens, the 

 science of cosmic phenomena. On this earth in physical 

 and still more in chemical phenomena the matter stood 

 very differently. Here we have not to deal with a few 

 measurable quantities only. A large number of elements 

 or factors, of which only very few can be accurately 

 measured, combine to make up what we called in the last 

 chapter molar and molecular phenomena. In the study 

 of inanimate nature, astronomy the mechanics of the 

 heavens deals with the simplest relations : chemistry 

 the science of the changes which bodies undergo when 

 being combined or separated deals with the most com- 

 plicated side of reality. Physics occupy an intermediate 

 position, and thus we can also trace in the history of 

 physical research the twofold influence of the astronomical 

 method of inquiry on one side, and the chemical on the 

 other. 



But the general rule, that in chemical changes the 

 weight of all the constituents put together never changes, 

 was not the only numerical relation which came to the 

 aid of students of nature, when they, at the end of the last 

 century, betook themselves to exact measurements and 



