840 THE POPULAR SCIENCE MONTHLY. 



were still laborious, but sure ; M. Boussingault employed tbem, 

 and in a few years succeeded in, to a large extent, sketching the 

 great work which is still being prosecuted, without in any way 

 changing the programme which the masters had laid out nearly 

 fifty years before. His robust good sense was not deceived. He 

 saw how the problem could be approached with exact methods of 

 elementary analysis. If he had tried at this time to follow in M. 

 Chevreul's tracks and undertake the immediate analysis of agri- 

 cultural products, he would have been foiled. The time had not 

 come, and it is interesting to compare from this point of view his 

 first experiments on germination with those which he executed 

 forty years later, when the progress of organic chemistry had 

 made accessible what was not within reach at the beginning." 

 In his analysis of plant-foods and his studies of the origin of the 

 nitrogen in herbivorous animals, the rigor of his methods was 

 marked ; his conclusions were reached slowly, not from one or a 

 few experiments, but after a series of them. " One must know," 

 he would say, " how to criticise himself ; it is not till after he has 

 exhausted all objections that he can estimate the value of them, 

 and come to a conclusion." His labors were characterized rather 

 by the clear and precise view of the end to be reached, abundance 

 of observed facts, and lucidity of demonstration, than by ingenuity 

 of methods. It was only rarely that he permitted himself to in- 

 dulge in those bold and sjDecious generalizations which are so 

 pleasing to many and are so quickly forgotten ; and before the 

 end of his life he was cured of all disposition toward them. 

 " Skepticism, even a little harsh in regard to the labors of others, 

 had become habitual with him." 



With such slow deliberation and painstaking care he pursued 

 through more than thirty years, in his laboratory and upon his 

 farm at Bechelbronn, his experiments on the composition of plants 

 and their parts ; of soils and manures ; the effects of different soils 

 and different manures, of no soil (or only sand or gravel) and no 

 manure, of air as it exists and of air purified of all foreign ele- 

 ments, upon the growth of plants; varying the experiments in 

 every conceivable way, year after year, testing them one by an- 

 other, and comparing them one with another — all for the double 

 purposes of learning whence plants derive their nitrogen, and 

 what are the best kind and form of fertilizing material for each 

 plant and for each kind and condition of soil. The first question 

 is still not solved. On the other side, the investigations have con- 

 tributed greatly to the improvement of agricultural methods and 

 to the rewards of wise cultivation. The results of these studies are 

 embodied in the " Rural Economy " and the " Agronomy," and in 

 such papers in the journals of scientific societies as those on " The 

 Estimation of Ammonia in Waters " ; on " The Quantity of Am- 



