TO TEACHERS AND STUDENTS. 



THERE is no easy method of acquiring knowledge. It 

 is only to be obtained by close attention and unceasing 

 labour. To become usefully learned in any branch of hu- 

 man knowledge, no matter what may be the quality of his 

 faculties, every man must toil and take advantage of all 

 the means within his reach. 



It has been asserted that, to become familiar with any 

 branch of physical science, it is only necessary to see with 

 the eyes and hear with the ears, without resorting to other 

 means. It is contended, for example, that Natural History 

 is best studied without " the use of any books whatever, 

 except the book of nature and its visible illustrations." 

 This notion is entertained by persons of so much learning 

 and influence, that it is worth our time to inquire briefly, 

 whether the plan has pretensions that should lead to its 

 general adoption. 



He who reads only, and draws all his knowledge from 

 books, may perhaps become very learned, a skilful rheto- 

 rician, a formidable critic, the author of brilliant theories, 

 the inventor of some ingenious system, but he will never, 

 by this means alone, be able to practice usefully, what he 

 has thus learned ; and, in most instances, it will be found, 

 that instead of having acquired ideas of practical applica- 

 tion, the memory has been filled only with words. 



The student who is content to follow lectures, w^ill not be 

 more successful. One learns less in this way than by 

 reading good authors. By reading, we may correctly per- 

 ceive the thoughts and opinions of an author, without much 

 danger of attributing to him the reverse of what he has 

 written or wished to express. If there i3 any uncertainty 



(xi) 



