December 18th, 1919.] Proceedings. xxxiii. 



products could command the highest prices. After these come 

 motor spirit, then illuminating oils, then heavy oils for oil 

 engines, and lastly furnace oils. Therefore the suppty of 

 furnace oils will suffer most by the introduction of cracking. 



The majorit}- of the people engaged in the petroleum indus- 

 try do not expect any petrol shortage, at any rate for several 

 years to come, in spite of the rapidly increasing demand. 



The shale oil supply is less than 'J, per cent, of the world's- 

 petroleum supply. 



Benzol is at present the main petrol substitute. The principal 

 sources of benzol are coal tar and coke oven gas. Gray and 

 Mellanby estimate the possible 3'ield in the United Kingdom, 

 if all benzol were recovered from these sources, as follows : — 



From coal tar 2 million gallons per annum. 



From coke oven gas... 26 ,, ,, ,, 



An enormous increase in the coal production does not appear 

 probable in the near future, and therefore benzol is not likely 

 to satisfy any large portion of the demand for motor spirit. 



The actual production of benzol at the present time is about 

 10 per cent, of the quantity of petrol imported, and a large part 

 of this is taken up by industries which are in a position to 

 afford higher prices than are acceptable to motorists. At the 

 best, benzol will only make a slight addition to the motor fuel 

 supply. In the opinion of the speaker it will find its best 

 utilisation in the form of mixtures. 



The most promising source of petrol substitute at the present 

 appears to be alcohol. Though it is low in heat value (12,697 

 B.Th-U. gross) it has the advantage of requiring a small amount 

 of air for combustion, and it possesses a high ignition point, 

 and is therefore able to withstand high compression pressures 

 in internal combustion engines. In a suitably designed engine 

 it yields about the same power per gallon as petrol. The 

 possibilities of production of fuel alcohol in this country are not 

 very promising. Dr. Ormandy, who has specialised on this 

 subject for many years, informs me that he considers the most 

 suitable method of preparation to be by the alcoholic fermenta- 

 tion of vegetable matter, and that the necessary vegetable 

 substances can be most economically grown in tropical or sub- 

 tropical countries. The calcium carbide process could not under 

 existing conditions compete with the fermentation process as. 

 regards cost of production. 



There is one more point to which 1 should like to call atten- 

 tion, and that concerns the methods used in valuing motor 

 spirits. Hitherto motor spirit anatysis has consisted of routine 



