NITKATES FROM ATMOSPHERE SCOTT. 367 



As the electric arc gives in an easy manner the temperature above 

 ignition point it is principally used. Some experimenters contend, 

 however, that if by using a flame of carbon monoxide or a sprayed 

 oil flame of carbohydrates a temperature near that of the electric 

 arc was reached, then the results would be equally satisfactory. They 

 point out that the ignition of nitrogen and oxygen takes places at 

 1,800° C, and as the temperature of the electric arc is well over 

 2,000° C, it is really much lighter than is necessary. 



It is not at all certain, however, that the effect is merely due to 

 temperature. A more probable theory is that some of the oxygen is 

 first formed into ozone and that farther on in the arc the extra atom 

 of oxygen splits off', and being in a nascent condition readily com- 

 bines with the nitrogen. In this connection it is interesting to note 

 that Sir. J. J. Thompson has demonstrated that under certain con- 

 ditions N3 does exist. Is it possible that O3 and N3 are first formed 

 and then the nascent atoms combine ? 



It is known that nitric acid is formed on the windings of high- 

 tension alternators and this is apparently due to silent discharge at 

 normal temperature and pressure. 



Mr. Cramp, whose investigations into this subject deserve to be 

 better laiown, says, in a communication to the writer, that he is quite 

 certain that ozone does enter into the problem, and that if the air 

 charged into the furnace had ozone mixed with it, there would be 

 an increased yield of fixed gas. A very small amount of ozone is 

 likely to have a considerable effect; 12 parts in 1^000,000 is a high 

 percentage. In the Central London Railway tube the percentage is 

 only 1 part in 1,000,000, and yet the ozone is so powerful that its 

 characteristic odor is quite noticeable. 



The photograph (pi. 1) shows that with alternating current the 

 arc concentrates on one side, and the fact that ozone is a conductor 

 may be partly or wholly responsible for this. 



On several occasions it has been suggested that the yield would 

 be higher if nitrogen and oxygen were passed through the furnace 

 in combining proportions instead of in proportions in which they 

 exist in air. Muthman says, however, that the proper proportions 

 are one of nitrogen to two of oxygen, and his explanation is that as 

 NO2 is easiest to form it is, therefore, formed first. 



Several methods of fixing nitrogen have been proposed which do 

 not depend on electric power. The principal one is due to Prof. 

 Haber, and it is of special interest just now, because the powerful 

 German company, the Badische Anilin und Soda Fabrik, is experi- ^ , 

 menting with it. JJ, 



The gases nitrogen and hydrogen in the proportions for forming ^ 



into ammonia are brought together under a pressure of 175 atmos- 

 pheres, and they are said to combine in the presence of a catalyser, 

 such as osmium or uranium. 



