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 



