BY J. C. BRUNNICH, F.I.C. 49 



of slime producing bacteria, proved the fixation of atmos- 

 pheric nitrogen by Azotobacter, and summarised the work 

 of such friendly bacteria (proceedings of the Linnean 

 Society of N.S.W., vol. XXXI., p. 615), by stating : "We 

 are now certain of the kind of help which the bacterium 

 gives the plants. There exists a symbiosis ; the plant 

 supplies saline and saccharine matters, the latter of which 

 the bacterium converts into gum, and at the same time 

 elaborates atmqspheric nitrogen into constituents which 

 are partly contained within the bacterial cell, and j)artly 

 diffused in the gum, which by virtue of their presence, 

 appears as a slime. Both the nitrogenous and the carbo- 

 hydrate constituents of the slime are then elaborated by 

 the plant-cells into tissue elements." 



A further supply of nitrogen in the form of artificial 

 fertilizer is frequently absolutely necessary, and hitherto 

 farmers of the whole world have been depending largely 

 on the supply of saltpetre fields of Chili. With an annual 

 output amounting to 1,740,000 tons in 1907, a depletion 

 of these mines is expected within 50 years, and the neces- 

 sity of some other source of nitrogen becomes very 

 apparent 



Birkeland and Eyre are now producing nitrates from 

 the atmospheric air at their factor}^ at Nottoden, Norway, 

 by electric discharges, thus reproducing one of Nature's 

 processes. An enormous supply of water produces the 

 cheap electric power necessary for heating the special 

 electric furnaces through which air is passed, and the 

 nitric acid obtained by the direct combination of nitrogan 

 and oxygen is absorbed by milk of lime, to form calcium 



nitrate. 



Another new nitrogenous manure is the calcium 

 Cyanamide, produced by the action of atmospheric nitrogen 

 on calcium carbide, the well-known compound used for 

 the production of acetylene gas, or on a mixture of lime 

 and charcoal, heated to 2000 degrees C. The ]>roduct 

 Cyanamide, or Kalkstickstoff , contains from 14 to 22% 

 of nitrogen, which is given off in form of ammonia, when 

 water acts on the substance in the ground. Experiments 

 carried out with the fertilizer seem to give excellent results. 



Another very important line of investigation in agri- 

 cultural chemistry and physiological chemistry is the study 



