ATMOSPHERIC NITROGEN 



' 05 



tected from dust, and were watered with distilled 

 water. But little growth was made. At the end of 

 two months the plants were submitted to chemical 

 analysis, and the amount of nitrogen present was 

 determined. 



His first results are given in the following table : 39 



Nitrogen. 



In seed sown. 

 Gram. 



Clover, 2 mos o. 1 1 



3 " 0.114 



Wheat 2 " 0.043 



" 3 " 0.057 



Peas 2 " 0.047 



Boussingault concluded that when plants, in a 

 sterile soil, were exposed to the air, there was with 

 some a slight gain of nitrogen but 

 the amount gained from atmospheric 

 sources was not sufficient to feed the 

 plant and allow it to reach full ma- 

 turity. By many these results were 

 not accepted as conclusive. 



112. Boussingault' s Second Ex- 

 periments. — Fifteen years later 

 (1853) Boussingault repeated his ex- 

 periments in a different way. The 

 plants were grown in a large carboy 



with a limited volume of air so as to Fi g- 2 3- Plants grown 



in carbov. 



cut ore all sources of combined nitro- 

 gen, as ammonia. By means of a second glass vessel 



