122 EXPERIMENT STATION RECORD. 



The development of methods and the histoiy of investigations on which they 

 are based is traced, the principles and efficiency of some of the more successful 

 methods are discussed, the essentials of a commercially successful method are 

 enumerated, and the Birkeland and Eyde method, which it is claimed in large 

 measure fulfills these conditions and is the most efficient yet proposed, is 

 described. It has been shown that by this process, with cheap water power, 

 nitric acid can be produced at a cost of less than 1.2 cts. per kilogram for energy 

 or less than one-tenth of the present price of nitric acid. The most important 

 factor affecting cost is the concentration of the dilute nitrous gases obtained. 

 " This problem has not yet found its technical solution, doubtless it will be 

 solved." Progress has been made in this direction by Birkeland and Eyde, 

 resulting in the production of a basic calcium nitrate. 



Other methods of utilizing the atmospheric nitrogen are briefly considered. 

 Of the 4 methods thus far proposed 8 are fheniical and 1 bacteriological. 

 " The bacterial absorption of nitrogen is, at present, confined to leguminous 

 plants, and unless a more active breed of bacteria can be developed, bacterial 

 action, while valuable, can not replace the use of Chile saltpeter. The formation 

 and decomposition of nitrids is the second method." Technical difficulties have 

 thus far prevented the development of methods based upon this principle. 

 " The third method is Frank's well-known process, in which pure nitrogen, not 

 air, is absorbed by heated calcium carbid, forming calcium cyanamid, which is a 

 valuable fertilizer. This process is on trial technically. Whether the calcium 

 cyanamid can compete with the synthetic nitrate is doubtful. The fourth 

 method is the nitrogen oxidation." 



Nitrogenous fertilizer from the air (Mark Lane Eirpress. .94 (1906), Nos. 

 S881, Pert, and Feed., p. Ill; 388^, Pert, and Feed. p. //).— Papers by Professor 

 Silvanus Thompson, already )ioted (E. S. R., 17, p. 829), and by Sir William 

 Ramsay in the Engineering Supplement of the London Times, are briefly 

 reviewed with reference to the following features: (1) The necessity of a 

 tuiure new source of nitrogen for agriculture, (2) methods of production, and 

 (3) fertilizing value of the products. 



The general conclusion drawn from the review of these papers is " that agri- 

 culture will not languish from want of nitrogen when the nitrate of soda 

 deposits have died a natural death from exhaustion ; but that inexhaustible 

 supplies will be available, and probably at lower prices." 



The electric production of nitrates from the atmosphere (Nature [London], 

 7.5 (1006), Xo. 1893, pp. .3.5 J, 356').— This is an abstract of an address by S. P. 

 Thompson, which has already been referred to (E. S. R., 17, p. 829), discussing 

 especially the success of the Birkeland and Eyde process in Norwaj'. 



It is stated that in the experimental factories using this jirocess 500 kg. of 

 nitric acid per year have been produced for every kilowatt of power. " The 

 conditions in Norway were exceptionally good for the furnishing of power at 

 exceedingly low rates. Hence the new product could compete with Chile salt- 

 peter on the market, and would become every year more valuable as the demand 

 for nitrates increased and the natural supplies became exhausted." 



New fertilizers prepared from atmosiDheric nitrogen, C. Dussekre (Chron. 

 Ayr. Yaud, 19 (1906), No. 5, pp. 123-127). — Experiments with lime nitrogen on 

 potatoes are reported, and the probable value of calcium nitrate prepared l)y 

 electrical methods is discussed. 



Water power in Norway and the future of the Birkeland and Eyde dis- 

 covery, L. Grandeau (Joirr. Agr.^Prat., ii. ser.. 11 (1906), No. 12, pp. 361, 362, 

 fig. 1). — Statistics are given of the horsepower of various waterfalls (aggre- 



