234 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
As early as 1755 Priestly had noted that nitrogen compounds were 
formed when electric sparks were passed through air, and not long 
after Cavendish produced saltpeter by absorbing air, so treated, in 
caustic potash solution. Repeated attempts have been made since 
high potential currents have become readily available to utilize this 
method and an establishment was erected at Niagara Falls, by the 
Atmospheric Products Company, to operate the Bradley and Lovejoy 
process. This method, for which a United States patent was granted 
September 30, 1902, consisted in producing in the air a flaming elec- 
tric are of minimum volume by the rapid rotation of electrodes 
carrying high tension currents, but while it yielded nitric acid the 
method proved too costly. 
A more successful device was shortly after put into operation by 
Birkeland and Eyde? at Nottoden, Norway, and it has been in opera- 
tion ever since. In this the flaming ares produced by high tension 
currents were made to move to and fro through the air within the 
apparatus by exposure to powerful magnets. This apparatus was 
characterized by a narrow chamber through which the air was passed 
and within which the electrodes, placed near together, were arranged 
between the poles of a strong magnet and at right angles to these 
poles. A disk-shaped or deflected electric arc was thus obtained 
perpendicular to the lines of force of the magnetic field. Three 
such furnaces at Nottoden, using 500 kilowatts and 5,000 volts, gave 
deflected arcs about 3 feet in diameter. The nitrogen oxides formed 
were quite dilute and they were carried to absorption towers where, 
by contact with milk of lime, calcium nitrate was formed, the product 
being eventually converted into basic calcium nitrate for use as a 
fertilizer. According to O. N. Witt,’ with this apparatus an output 
of 500 to 600 kilos of nitric acid per kilowatt year can be regularly 
maintained, 
A still more efficient form of furnace is that devised by Dr. Otto 
Schoenherr for the Badische Anilin and Soda Fabrik. From his 
lecture, delivered June 11, 1908, before the Verein Deutscher 
Chemiker at Jena, it appears that what is sought in these processes 
is to burn the nitrogen with the oxygen of the air. To accomplish 
this to any satisfactory degree the gases must be exposed to a tem- 
perature of 3,000° C. and upward. To prevent the decomposition of 
the product formed it must be immediately removed to a cooler 
region. This Birkeland and Eyde accomplish through moving the 
are to and fro by the aid of magnets, while Shoenherr effects it by 
imparting to his air a gyratory motion about his elongated are. 
His apparatus consists of a long iron tube in which an arc 5 meters 
“The Electrochemical Problem of the Fixation of Nitrogen, Phillippe A. Guye, 
J. Soc. Chem. Ind., 25, 567, 1906. 
’Chemiker Industrie, 28, 699, 1905. 
