86 LETTER-FILES OF S. W. JOHNSON 



and instruct the philosopher, but for the farmer its value is 

 small, if he has to pay for it. It is only by the application of 

 the general principles which may be developed from numer- 

 ous analyses, that he can hope to be directly benefited. 



But what shall the farmer do ? Shall he grope in the dark ? 

 No ! But let him beware of false lights which are now-a-days 

 hanging out in abundance. Let him beware of taking advice 

 from two dangerous characters, the conceited farmer who 

 knows a little science, and the officious philosopher who knows 

 a little farming. 



In October, he wrote on the practical value of the 

 analysis of plants: 



The natural history, the chemistry, in short the whole 

 science of each agricultural plant, must be made the subject 

 of careful investigation. The knowledge of the general condi- 

 tions of vegetable growth has arrived at a pretty high state 

 of culture. We must henceforth seek to learn those special 

 conditions which determine the utmost development of indi- 

 vidual species. Science and Practice, the laboratory and the 

 farm, have this business to perform together. Every plant 

 can be put into such circumstances as will make it tell what 

 it needs for its successful growth. . . . 



I trust that in this and a preceding article, I have written 

 nothing to discourage Agricultural Education, or destroy the 

 farmer's confidence in science. If any one promulgates false 

 doctrine in the name of science, he will be found out in time. 

 Truth remains and has a permanent value, no matter who 

 defends or opposes it. My object has been to define the limits 

 within which chemical analysis cannot be practically applied. 

 I desire to give chemistry all the credit it deserves, and have 

 too much regard for that beautiful science to bring upon it 

 future contempt by loading it with present adulation. 



In a letter written from Stuttgart, April 1855, pub- 

 lished as "Foreign Correspondence," Mr. Johnson 



