PART V. THE FUTURE OF FERTILIZERS 



SECTION I. NEW SOURCES OF FERTILIZERS 



Nitrogen Fertilizers. The better utilization of atmo- 

 spheric nitrogen may be looked forward to as a means of 

 increasing our supplies of nitrogenous fertilizers. As yet it 

 is too early to form any definite opinion as to which methods 

 will prove the most satisfactory. The use of the electric 

 arc furnace involves much electric power, but, on the other 

 hand, requires only one factory, only two processes, and can 

 easily be worked intermittently. As the whole process is 

 worked entirely by electric power, merely switching off the 

 current stops the whole machine. In the future one may 

 look for some improvement in this process, since undoubtedly 

 many furnaces are faulty, because a large proportion of the 

 air passing through cannot possibly come into contact with 

 the arc. The fears of insufficient electric power to work 

 this process are not altogether justified. Although it is 

 generally considered that water power is essential, yet, as 

 a matter of fact, electric energy obtainable from coal has been 

 sold at very low prices in the county of Durham. The utili- 

 zation of waste energy has still scope for large future develop- 

 ments ; there are innumerable .industrial concerns where 

 there is very much waste of heat, which can easily be turned 

 into steam, and thence into electric energy. Where waste 

 heat from coke ovens is procurable, the arc process presents 

 the advantage that electric power can be used to make nitric 

 acid, which is then subsequently combined with by-product 

 ammonia ; the ammonium nitrate so formed contains a high 

 percentage of nitrogen and is obtained without adding any 

 outside materials. Up to the present the manufacture of 

 nitric acid by electricity, obtained from waste heat, has made 



