OF NATURAL PHILOSOPHY. 191 



fetters, but rather like that of the freeman who has 

 learned the lessons of self-restraint in the school of 

 just subordination. The ultimate objects we pursue 

 in the highest theories are the same as those of the 

 lowest inductions ; and the means by which we can 

 most securely attain them bear a close analogy to 

 those which we have found successful in such in- 

 ferior cases. 



(202.) The immediate object we propose to our- 

 selves in physical theories is the analysis of pheno- 

 mena, and the knowledge of the hidden processes 

 of nature in their production, so far as they can be 

 traced by us. An important part of this knowledge 

 consists in a discovery of the actual structure or 

 mechanism of the universe and its parts, through 

 which, and by which, those processes are executed ; 

 and of the agents which are concerned in their 

 performance. Now, the mechanism of nature is 

 for the most part either on too large or too small a 

 scale to be immediately cognizable by our senses ; 

 and her agents in like manner elude direct observ- 

 ation, and become known to us only by their effects. 

 It is in vain therefore that we desire to become 

 witnesses to the processes carried on with such 

 means, and to be admitted into the secret recesses 

 and laboratories where they are effected. Micro- 

 scopes have been constructed which magnify more 

 than a thousand times in linear dimension, so that 

 the smallest visible grain of sand may be enlarged 

 to the appearance of one a thousand million times 

 more bulky ; yet the only impression we receive by 

 viewing it through such a magnifier is, that it re- 

 minds us of some vast fragment of a rock, while the 



