NEW SOURCES OF FERTILIZERS 225 



little progress because more profitable enterprises have been 

 open to those who possessed the necessary machinery. To 

 some extent these developments have been dependent upon 

 war needs, and the future may show a greater temptation to 

 the owners of waste heat to utilize it for the production of 

 nitric acid. 



The Haber Process of Synthetic Ammonia. This 

 process involves many practical difficulties of an engineering 

 type, but it is chemically simple, and is comparatively self- 

 contained. It may be taken almost for granted that the 

 German Badische Anilin Fabrik will install plant outside 

 Germany, and other countries have already produced workable 

 plants, while competition will gradually improve the process. 

 The Haber process claims to be able to produce ammonia 

 very cheaply, and if the difficulties of construction can be 

 surmounted there does not seem to be any reason why this 

 claim should not be made good (see p. 93). 



The Cyanamide Process. This process is more com- 

 plicated and circuitous than the methods named above, but 

 up to the present more nitrogen has been fixed by this method 

 than by any other. The first product, calcium carbide, 

 is important, as it is used for the production of acetylene ; 

 the furnaces producing calcium carbide will therefore be 

 kept in employment, even if nothing further is done. The 

 next step produces calcium cyanamide, a manure which can 

 be used directly on the land. The cyanamide produced 

 can be converted into ammonia, and the ammonia can be 

 converted into ammonium sulphate, or, alternatively, it 

 can easily be oxidized into nitric acid. There is, therefore, 

 a much greater security with this process than the others, 

 since a readier market can be found for all its products. 

 Probably there will remain room for the three different 

 processes. The arc process produces nitric acid directly ; 

 the Haber process yields ammonia, which can be oxidized to 

 nitric acid ; and the cyanamide process can hold its own under 

 any conditions. 



Nitrogen Fixation by Barium Oxide. Mixtures of 

 barium oxide and carbon, when heated, absorb nitrogen, 



v. 15 



