740 EXPERIMENT STATION RECORD. 



present the progress of agricultural science in such a way as to encour- 

 age this. His work was quite largely that of a compiler, and it was so 

 well done that the results were scarcely less useful to the practical 

 farmer than to the investigator. An idea of the extent to which his 

 writings reached the public is furnished by the statement of his pub- 

 lishers that 22,000 copies of his DUngcrlehre (Principles of Manuring) 

 and 30,000 copies of his Fiitferungslehre (Principles of Feeding) were 

 sold in the original. Furthermore, over 35,000 copies annually of his 

 tables of fertilizers and feeding stufts in Mentzel and von Lengerke's 

 Agricultural Calendar "found their way into the breast pockets of 

 practical farmers." Considering the numerous translations of his 

 works and that hardly a popular bulletin on the principles of feeding 

 is issued which is not based to a considerable extent on his writings, it 

 is evident that the influence of his books can not be estimated. They 

 have done much to bring about the practical application of scientific 

 teachings, and they have stimulated investigation in both practical and 

 theoretical lines. 



Prof. Georges Yille, like Wolff, possessed in an eminent degree the 

 capacity for popularizing scientific work in agriculture, and, next to 

 Liebig, he perhaps contributed more than any other man to the exten- 

 sion and systematizing of the use of commercial fertilizers. He accom- 

 plished this, it is true, largely by dogmatic teaching, much of which 

 has since been proved erroneous, but at the time it appealed strongly 

 to the practical agriculturist, whose constant demand is for scientific 

 rules and fixed formulas applicable under all conditions. He early 

 outlined and advocated a system of plat experiments for the purj)ose of 

 studying the fertilizer requirements of soils, which is substantially the 

 same as that followed in such work to-day. 



Ville was one of the first to maintain, on the basis of elaborate exper- 

 iments, that certain plants had the i)ower of assimilating the free nitro- 

 gen of the air, and his controversy with Boussingault on this point has 

 become classic. But he failed to discover the true explanation of 

 assimilation of free nitrogen by plants, suggesting that it was due to a 

 process of nitrification in the leaves of the plant. Later, when the 

 nitrogen assimilation .was explained by the investigations of others, he 

 became an euthusiastic advocate of the j)ractice of green manuring 

 with leguminous plants, accompanied by applications of lime, phos- 

 phates, and potash to maintain the fertility of the soil. 



At the beginning of the second empire Ville was appointed j)rofessor 

 of vegetable physiology in the museum of the Jardin des Plautes of 

 Paris, a position which he held at the time of his death. In connection 

 with this position he had the management of the experimental fields 

 at Vincennes, near Paris, where much of his most important work was 

 done. He died at Paris February 22, 1897, at the age of 74 years. 



