828 EXPERIMENT STATION RECORD. 



process can be made to yield a product capable of competing success- 

 fully with nitrate of soda in the markets of the world. 



The most recent and most notable development in the line of fixa- 

 tion of the nitrogen of the air for commercial purposes is, however, in 

 the nature of a return to the earlier methods of direct oxidation by 

 means of electric discharges. Prof. K. Birkeland, of the University of 

 Christiania, Norway, and 8. Eyde, a Norwegian civil engineer, have 

 devised a process for greatly increasing the size and efficiency of the 

 ordinary electric arc, so that oxidation of the nitrogen is more rapid 

 and is accomplished with much less expenditure of electric energy, 

 and hence at less cost than in preceding processes. 



A recent writer in describing the process says : " The inventors, 

 instead of working with arcs of the lowest possible amperage, make 

 the first technical application of a phenomenon previously known to 

 physicists, the action of the magnetic field on the arc." They use a 

 powerful current of electricity in the form of great glowing electric 

 disks, up to 6 feet in diameter, which are built up of arcs deflected by 

 powerful magnets. 



By means of powerful electromagnets placed vertically to the 

 electrodes, which are hollow and cooled with a stream of water, "the 

 arc formed between the electrodes is blown away, as it were, by the 

 influence of the magnetic field, and at once a new arc is formed, which 

 is blown away. This process can be repeated 1.000 times a second, 

 though in practice only a few hundred arcs per second are used. With 

 alternating current arcs and direct current magnetic field, or vice 

 versa, the arcs vibrate between the electrodes as circular disks." 

 There is thus secured the alternate heating (to 2,000° C.) and cooling, 

 and the rapid and thorough contact of the air with the most active 

 zone of the arc, which are essential to the highest oxidation efficiency. 



The efficiency of this process has been demonstrated in an experi- 

 mental factory near Notodden, Norway, which utilizes the unusually 

 cheap water power of that region for the production of the electrical 

 energy required. It is reported that the daily output of this factory 

 for the year during which it has been in operation is about 3,300 

 pounds of pure nitric acid, and the factory has been pronounced a 

 technical and financial success by the eminent authority, Otto N. Witt, 

 of Berlin. The success of the experimental factory has been such that 

 several larger establishments are being built at other places in south 

 Norway where cheap water power can be had. It is claimed that 

 these factories will utilize in the aggregate about 30,000 horsepower, 

 and that the company exploiting the patent has options on Norwegian 

 Avaterfalls capable of yielding 350.000 horsepoAver at very low cost. 



It is reported that nitric acid can be produced by this process at 

 less than one-tenth of its present cost. Owing, however, to the dilu- 

 tion of the products of oxidation the difficulty and expense is less in 



