I'KESIUKNTIAL ADDRKSS — SKCTloX A. 



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combustion engines ; but wasU' beat boilers are already in use, 

 and a more extended adoption of combined steam and internal 

 combustion i)lants ma>' be looked for in tlie future. 



Several large tirms are known to be at work on tbe gas 

 turbine ; at present it is merel}- in tbe experimental stage, but 

 altbougb tbere are difficulties to be overcome, it would be folly 

 to imagine tbat they are insuperable. 



The selection of a prime mover depends, in addition kj 

 efficiency, upon other factors; Imt, in the end. the tendency 

 must be towards the adoption of the most efficient engine. The 

 internal combustion engine has now established its claim to 

 reliability as well as efficiency, and that it will continue to make 

 progress in the future, even at a greater rate than it has in the 

 past, there cannot be the shadow of a doubt. 



Sf9m Enqioei 



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thrnact ^CfC/e[rfi»^\ ^CyehSia»l\ ^^rdeOiestl 



Fu\. 40.— Comparative diagrams of Heat Consumptions, per B.H.P. per 

 hour, of various types of Heat Prime Clovers. 



• Petrol and Petrol Substitutes. — The gradual increase in 

 the price of petrol, more accentuated recentl}% has served to 

 alarm the motoring public. The petrol supply is obtained by 

 the distillation ojf crude petroleum, and Fig. 41 shows that the 

 increase, for example, in the British imports, has far out- 

 stripped the production of crude oil. It is admitted that the 

 annual output is excessive as compared with i)robable available 

 supplies, and the demand is likely to continue at an increasing 

 ratio. Apart from the more extended use of the motor-car as 

 a means of locomotion and i^leasure, recent years have seen 

 an extraordinary development in the application of the petrol 

 motor to motor traction, to agriculture and to the general pur- 

 poses of a commercial community. And everyone must realise 

 how indispensable the spirit engine has become in modern w;n-- 

 fare. Without it the aeroplane and the air ship are impossible, 

 and the magnificent mechanical transport of the Allies, which 



