33° Journal of Agriculture. [8 June, 1907. 



world with nitrate for about a quarter of a century, but the yield has 

 steadily increased, and yet we find the trade to-day in a more flourishing 

 condition than ever it was. This is perhaps to be accounted for by the 

 increased value of the finished article, it being possible now to turn into 

 profit the inferior grades of the raw material or "caliche" in the pre- 

 paration of the 95 per cent, product. 



Artificial Processes. 



Nevertheless the exhaustion of the South American deposits is in- 

 evitable, and in view of its high agricultural value the withdrawal of this 

 commodity from the market can only be regarded in the light of a 

 calamity unless other ready sources of supply are discovered. Cognisance 

 of this danger has given the necessary stimulus to scientists throughout the 

 world with the satisfactory result, as stated in the introductory paragraph, 

 that several rational suggestions have been submitted, the practical worth 

 of which has yet to- be appraised. 



It is significant that these discoveries have been made in those coun- 

 tries that have maintained their position in the vanguard of agricultural 

 progress. The more prominent processes in vogue at the present juncture 

 may be tabulated as under: — 



I. Oxidisation of atmospheric nitrogen by hydro-electric process. 



a. Lovejoy and Bradley, Niagara. 



b. Birkeland and Eyde, Notodden. 



II. Compounding of atmospheric nitrogen and calcium carbide by 

 electric furnace. 



a. Cyanid Gesellschaft, Berlin. 

 III. Bacterial oxidation of ammoniacal compounds in peat. 



a. Muntz and Laine. Still in the experimental or 

 laboratory stage. 



Lime Nitrate. — The oxidisation of atmospheric nitrogen by means of 

 electricity has been an established fact for many years, but the difficulty 

 of obtaining cheap power has hitherto been regarded as an insurmountable 

 obstacle to the economic production of nitric acid by this process. How- 

 ever, the utilisation of cheap water power would appear to have met this 

 difficulty, as we find that both the Niagara (U.S.A.) and Notodden 

 (Norway) factories are dependent for their success on the rights they have 

 secured over the adjacent waterfalls. Professor Birkeland and Mr. S. 

 Eyde have obtained the sole use of the Svaeljfos fall, the strength of 

 which is estimated at about 29,000 h.p., and they also hold a right of 

 purchase over the Rjukfas falls which will supply an additional 

 220,000 h.p. 



The essential feature of the hydro-electric process is the continuous 

 transmission of an electric flame through ordinary air by which means 

 nitrous and nitric acid vapours are generated. These are then passed 

 into towers where they are absorbed and transformed into nitrate of lime. 

 This crude product is next converted into a basic salt which keeps quite 

 dry, and so flows readily through the feeders and coulters of the drill. 

 The advantages claimed for the Norwegian process are its simplicity and 

 the employment of a special flame discovered by Professor Birkeland. 

 Experiments to test the value of this fertiliser are not yet published, but 

 it is anticipated by those who have inspected the trial plots at the Nor- 

 wegian Agricultural College that it will compare very favorably with the 

 alkaline nitrates particularly on soils deficient in lime. 



