174 DISCOURSE ON THE STUDY 



former phenomena which have resisted previous 

 efforts. It can hardly be pressed forcibly enough 

 on the attention of the student of nature, that there 

 is scarcely any natural phenomenon which can be 

 fully and completely explained in ah 1 its circum- 

 stances, without a union of several, perhaps of all, 

 the sciences. The great phenomena of astronomy, 

 indeed, may be considered exceptions ; but this is 

 merely because their scale is so vast that one only 

 of the most widely extending forces of nature takes 

 the lead, and all those agents whose sphere of action 

 is limited to narrower bounds, and which determine 

 the production of phenomena nearer at hand, are 

 thrown into the back ground, and become merged 

 and lost in comparative insignificance. But in the 

 more intimate phenomena which surround us it is 

 far otherwise. Into what a complication of different 

 branches of science are we not led by the consider- 

 ation of such a phenomenon as rain, for instance, 

 or flame, or a thousand others, which are constantly 

 going on before our eyes? Hence, it is hardly 

 possible to arrive at the knowledge of a law of 

 any degree of generality in any branch of science, 

 but it immediately furnishes us with a means of 

 extending our knowledge of innumerable others, 

 the most remote from the point we set out from ; 

 so that, when once embarked in any physical re- 

 search, it is impossible for any one to predict where 

 it may ultimately lead him. 



(184.) This remark rather belongs to the inverse 

 or deductive process, by which we pursue laws into 

 their remote consequences. But it is very important 

 to observe, that the successful process of scientific 





