102 SOILS AND FERTILIZERS 



mission to review the work of Ville. The commis- 

 sion consisted of six prominent scientists. They 

 reported that U M. Ville's conclusions are consistent 

 with his labor and results." 39 



118. Work of Lawes and Gilbert. A little later 

 L,awes and Gilbert carried on such extensive ex- 

 periments under a variety of conditions as to remove 

 all doubt regarding the question. Plants were grown 

 in sterilized soils, in prepared pumice stone, and in 

 soils with a limited and known quantity of nitrogen 

 beyond that contained in the seed. Different kinds 

 of plants were experimented with. The work was 

 carried on with the utmost care and with apparatus 

 so constructed as to eliminate all disturbing factors. 

 The results in the aggregate clearly indicate that 

 plants, when acting in a sterile medium, are unable 

 to make use of the free nitrogen of the air for the pro- 

 duction of organic matter. 39 . 



119. Atwater's Experiments. Atwater carried on 

 similar experiments in this country. 41 His results 

 indicate that when seeds germinate they lose a 

 small part of their nitrogen, and that when legumes 

 are grown in a sterile soil, but are subsequently ex- 

 posed to the air, a fixation of nitrogen may occur. 



120. Field and Laboratory Tests. By a five years' 

 rotation of clover and other leguminous plants, Lawes 

 and Gilbert found tha4: a soil gained from two to four 

 hundred pounds of nitrogen per acre, in addition to 

 that removed in the crop, while land which produced 

 wheat continuously had gradually lost nitrogen. The 



