422 SEcrnONAL COMMUNICATIONS. 



of the normal by absorption under 3 atmospheres pressure in chromium- 

 nickel-steel towers. 



Although bombs have proved perfectly satisfactory in operation, 

 there remains the possibility of substituting a gas-engine, or preferably 

 a modified type of Humphrey pump, for the explosion bombs. It is 

 possible that a greater percentage of the calorific value of the gases or 

 liquid fuels used could thus be converted into useful energy. Such 

 plant would necessarily be of a more complicated nature than a bomb 

 installation, and it is doubtful whether there would be any real gain 

 on balance. Finally, the importance of using gases of higher calorific 

 value as giving higher temperatures and yields is emphasised, and 

 methods are indicated by which coke-oven and similar gaSes can be 

 enriched to meet these conditions. It is suggested that Hausser plants 

 can be usefully developed either as adjuncts to synthetic ammonia 

 plants, at coke-oven plants, or in places where liquid fuel is cheap and 

 the cost of making nitric acid is relatively high 



Dr. E. B. Maxted. — Some Aspects of the Relation between Water 

 Power and Nitrogen Fixation. — Nitrogen fixation processes involve two 

 economic factors, power and material, the relative importance of which 

 will determine not only the most suitable site in a given country, but 

 also the practicability of the method under given geographical and 

 mineralogical conditions. For the arc process the availability of cheap 

 electrical energy is the determining factor, whilst the ammonia process 

 is co'mparatively independent of such conditions, cyanamide occupying 

 an intermediate position. In 1914 some 50,000 tons of British anthra- 

 cite were exported to Norway for the manufacture of carbide. Under 

 British conditions, except for the manufacture O'f nitric acid as such, 

 probably only the cyanamide and the ammonia synthesis processes are 

 practicable. The ammonia process would be almost independent oi 

 power but' for the fact that the hydrogen may be manufactured electro- 

 lytically as an alternative to the process in which water-gas is prepared 

 from fuel. 



The Water Power Resources Committee has reported on resources in 

 Great Britain estimated to be capable of producing some 250,000 kw., 

 exclusive of the Severn Estuary scheme. Of the ten Scottish sites 

 I'eported on favourably only one was estimated to produce over 

 30,000 kw., and of the five Welsh sites only one over 5,000 kw. Sites 

 producing less than 10,000 kw. are not suitable for cyanamide, whilst 

 the minimum for the synthesis of ammonia has not yet been determined. 

 An average figure for the cost of power at the Scottish sites would be 

 about SOL on a pre-war basis for each kw. Operating and other costs 

 should not be more than 3 per cent, of the capital cost. Several of the 

 more suitable sites should produce power for about 4Z.-5L per kw.-year, 

 the cost at certain Norwegian plants being 21.-31. imder pre-war con- 

 ditions. A figure of Is. 7d. per 1,000 cubic feet is obtained for the 

 cost of hydrogen with power at 5L per kw.-year, a figure comparing not 

 unfavom-ably with the cost from fuel, although nothing has been allowed 

 for the value of the oxygen produced. The electrolytic process, how- 



