J. H. Gilbert— Points in c 





Wed water, free m 





I 



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s 



ll 





ii 







































1858: Nitrate of Potassii 



mas Mai 



««.t 



Inehanthu* 



( 1 01441 



1 ss 



| -0-0014 1 0-90 









M. Boussingault's soils consisted of burnt soil, washed and 

 ignited pumiee, or burnt brick ; liis experiments were some- 

 times in free air, sometimes in a closed vessel with limito<l air, 

 sometimes with a current of washed air, and sometimes in free 

 air, but under a glass case. "When the plants were enclosed, a 

 supph ot < ill acid was provided, and in a few cases 



known quantities of nitre were supplied as manure. 



The last two columns of Table VI show the actual and 

 proportional gain of nitrogen in M. Boussingault's experiments. 

 It will be observed that in his earliest experiments, those in 

 free air, in a summer-house, the leguminous plants, trefoil and 

 peas, did indicate a notable gain of nitrogen ; but in all his 

 subsequent experiments there was generally either a slight loss, 

 or, if a gain, it was represented in only fractions, or low units, 

 of milligrams. After twenty years of varied and laborious 

 -mil of the subject," M*. Boussingault conclude.; that 

 plants have not the power of taking up and assimilating the 

 free nitrogen of the atmosphere. 



Our own experiments on this subject were commenced in 

 1857, and the late Dr. Pugh, of the Pennsylvania State Agri- 

 cultural College, devoted between two and three year- to the 

 investigation at Bothamsted. Mr. Lawes has contributed on« 

 complete set of the apparatus employed to this e 

 The arrangement, and the results obtained up to that date, 



* Ann. Ch. Phys., Ser. HI. xliii, (1855). % Compt. rend., ilvii, (1858). 



% Nitrogren in seed and nitrate. 



