Nov. 2, 1908.] Agricultural Gazette of N.S.W. 871 



1. Manufacture of Atmospheric Nitrates. 



1 JlKKELAND- E VDE PkOCE.SS. 



In October, last year, Professor Thompson, in an article in The 

 WorUrs Work, entitled, "When wheat fails," shows how electricity may be 

 utilised to produce the new fertilising agent, nitrate, with the object of 

 ensuring the continuance of an adequate supply of grain. That nitric acid 

 can be generated by the chemical combination of nitrcjgen and oxygen, by 

 means of an electric spark, has been a known fact for more than a century, 

 but the production of nitrates on a scale which promises to be of commercial 

 advantage is a scientific achievement of very recent date, and Professor 

 Thompson explains the processes. 



Ten years ago certain experiments Sir William Crooke was making in 

 this direction strongly suggested a possible solution of the food problem. 

 He came to the conclusion that if the supply of electric energy could be 

 generated at a cost of 1-17 of a Id. per unit (i.e., per kilowatt hour), nitrate 

 of soda could be manufactured at £-5 per ton. Chilian saltpetre, nearly 7-5 

 per cent, of the output of which is used for manuring wheat-fields, sells at 

 the present time at more than double this price. 



Since the time of Crooke's experiments, the fixing of atmospheric nitrogen 

 has become an accom23lished fact ; in Scotland and Germany in connection 

 with raining products ; and, finally, in Norway a factory has been success- 

 fully established where, under the name of Norwegian saltpetre, nitrates are 

 directly produced from the atmosphere on a commercial scale. Discoveries 

 made by Professor Kristian Birkeland in the course of certain investigations 







\ 



Group of Birkeland-Eyde Electric Furnaces, each of 800 h.p. 



in connection with the phenomena of the Aurora Borealis, led eventually to 

 fin-ther examinations into the action of a transverse magnetic field upon an 

 electric arc, formed when an alternating electric current is passing between 

 the tips of two conducting rods, the result being the pi-oduction of pure nitric 

 acid. The acid is absorbed by treatment with limestone and caustic lime, 

 thereby producing nitrate of lime. This product is concentrated and packed 

 in canisters. The Professor's collaborator in this achievement was Samuel 

 Eyde, a Christiana engineei'. 



