APPLICABLE TO PHYSICAL SCIENCE. 295 



(204.) The power of analogy, thus so ably illus- 

 trated in the case of religion, is precisely as strong 

 when applied to £he elucidation and confirmation 

 of a theory in physical science. When once what 

 is supposed to be a general law of nature is dis- 

 covered, its truth and certainty becomes more and 

 more confirmed, in proportion to the variety and 

 severity of the tests applied to it. And if, after 

 tracing it, as widely as possible, through the almost 

 numberless groups of the animal world, it becomes 

 also apparent both in the vegetable and in the 

 mineral kingdoms, we have all the evidence that 

 human research or human wisdom can conceive, 

 that our theory is sound ; or, in other words, that 

 we have achieved the discovery of one of those 

 immutable truths which the wit of man can never 

 devise, or the power of time destroy. 



u 4< 



