I'KESIDKXriAl. AUDKIISS — SK( TlO.X A. 5/ 



coal, ihus incrca'^iiig :hc range; tlu' absence of sniukc ; and the 

 facility with which it may be transported and transferred to 

 ships, have caused the liiitish Government to adopt it almost 

 exclusivel}- for steam raisuig in warships. In this case it is 

 entirely a question of ethcieucy. There can be no doubt that 

 the wonder tul naval results achieved have Ijeen in large measure 

 due to the use of li([uid fuel and steam turbines. 



Caseous Fuel plays a most important part in many industrial 

 operations, which indeed in many cases could not be conducted 

 without it, and it renders available as a fuel millions of tons 

 of inferior coal which might otherwise be discarded. Natural 

 gas has been used since 1821 in the United States, which in 1914 

 produced 592,000 millions cubic feet, or 13,200,000 tons, this 

 being 96 per cent, of the world's outptit, and having a value of 

 £19,336,000. 



Since means have existed for its direct utilisation in the gas 

 engine, the use of gas as a fuel for boilers has greatly dimin- 

 ished, and would only appear to be justified when steam for 

 industrial purposes is required; the introduction of the "sur- 

 face combustion " method of burning gas in a boiler has enabled 

 thermal efficiencies of over 92 per cent, to be obtained, and 

 the method is now being introduced on a commercial scale. But 

 even with this high boiler efficiency, and tising blast ftirnace gas, 

 the overall efficiency could not equal that of the gas engine sup- 

 plied from a gas producer, on account of the higher thermal 

 efficiency of the internal combustion engine. 



In earlier days the gas from coke ovens was wasted or. at 

 least, used for firing boilers with no attempts at recovery of tar 

 and other bye-products ; now it is urged that the economic utilisa- 

 tion of coke oven gas is a matter of national importance. Coke 

 oven gas is a rich gas, perfectly suitable for use in gas engines, 

 and I have seen on the Continent a gas engine power plant of 

 20.000 k.w. working successfully with this hitherto wasted fuel. 



Internal Combustion Engines. — The advent of the internal 

 combtistion engine has changed the w-hole complexion of power 

 production. There is now available a great variety of fuels, 

 and these and the various types of prime movers may be classi- 

 fied as follows : — 



