NITKaTES from Al'MOSPHERE — SCOTT* 377 



IV) is perhaps the most interesting. Gas is generated from cheap 

 brown coal and used in gas engines to generate the electric current. 



Although calcium cyanamide is mostly employed as a manure, it 

 has other uses. For example, by treating with superheated steam 

 very pure sulphate of ammonia is obtained. Also ammonium nitrate 

 and dicyandiamide are made from it. 



EXPLOSIVES. 



Although manures form the main outlet for the products of these 

 electric fixation of nitrogen processes, there are other important uses. 



At the Notodden saltpeter factory ammonium nitrate is made by 

 bringing the nitric acid into contact with ammonia liquor from our 

 English gas works. The ammonia nitrate crystallizes out, and when 

 dry it contains 35 per cent of nitrogen, and it sells in this country at 

 about £27 a ton. It is the principal constituent of many of the ex- 

 plosives for mines. 



Dicyandiamide, CoN^H^, which is made by treating calcium cyana- 

 mide with water, when it crystallizes into broad needles or prisms 

 is being used for mixing with explosives. It contains 66 per cent of 

 inert nitrogen, and is used for lowering the temperature of the ex- 

 plosion. 



This is of importance, because orclnance powders rapidly destroy 

 rifling in guns on account of the high temperature. The importance 

 of this is shown by the statement made publicly in 1905 that the 12- 

 inch gun Mark VIII used on 15 British battleships could not stand 

 more than 50 rounds full charge. 



Nitric acid is, of course, the main constituent of guncotton, dyna- 

 mite, and smokeless powders, etc., and at the present time we are 

 mainly dependent on over-seas supplies of raw material from which 

 to make the acid. In case of war we should undoubtedly be in a very 

 serious position, for whereas most continental countries have plants 

 for the fixation of nitrogen from the air, this country does not make 

 a single ounce. 



It will be remembered that at the time of the Napoleonic wars the 

 French had difficulty in obtaining saltpeter with which to make pow- 

 der; it behooves us, therefore, not to be caught in the same predica- 

 ment. A few rounds from a broadside of modern guns blows away 

 into the air as much nitrogen as was used during the whole course 

 of a war of the last century. The necessity of having factories where 

 explosives can be made to any amount, and quite independently of 

 raw materials from overseas, is therefore obvious. Even if the prod- 

 uct could not at first compete in price with existing supplies, the fact 

 that it was a necessary addition to our national assurance against war 



