xvii UTILISATION OF THE SOIL 205 



What Liebig did for Kappes, he did really for 

 the world ; for our bread and meat to-day would be 

 much dearer than they are were it not that Liebig 

 had taught the farmers the value of mineral manures. 



Much about the same time that Liebig was 

 working at this subject, a French agricultural 

 chemist, called Boussingault, was also interesting 

 himself in the chemistry of plants. In his book on 

 Rural Economy he speaks of the difficult subject of 

 the source of plant nitrogen, and of a series of 

 experiments he made in connection with it. 



Let us quote a few words from this book, in 

 connection with these experiments: 



" I had necessarily," he says, " to follow a method 

 of inquiry different from any which had yet been 

 taken ; I had no chance of arriving at more definite 

 results than those which had been already come to, 

 had I chosen the old line of investigation. I there- 

 fore called in the aid of elementary analysis, with 

 a view of comparing the composition of the seed 

 with the composition of the harvest produced from 

 it, at the sole cost of water and the air. By pro- 

 ceeding in this way I believed that the problem 

 was capable of solution ; without flattering myself 

 that I have completely resolved it, I conceive that 

 something has been done in the right direction. 

 The subject is one of the most delicate imaginable, 

 and he who enters it requires indulgence." 



