486 



TRANSACTIONS OF SECTION G. 



is really needed, provided always that the engine is properly correlated to the 

 producer and the latter to the quality of the fuel and rate of combustion. 

 Figures representing the consumption of lubricating oil were also given, as being 

 of special interest in view of the criticisms that have sometimes been made in this 

 respect. The experiences of users with regard to the cost of maintenance and 

 repairs were also referred to. 



The question of capital outlay was next considered for engines and producers 

 fixed complete upon foundations, with piping and all accessories. No figures were 

 quoted for buildings or space occupied, as, after all, these items, though of 

 importance, vary so much in value that no useful purpose would be served by any 

 assumption. 



Having thus dealt with the more important corsiderations that come under 

 survey in the application of gas power, some attention was given to the comparative 

 costs of operation of liquid-fuel engines of the Diesel type, which, although more 

 efficient as regards utilisation of heat units available in the fuel for conversion 

 to power, yet require several conditions to be fulfilled before the higher economy 

 becomes apparent in the pocket of the manufacturer. Similarly, some points 

 were suggested with regard to the relative performances of steam engines of 

 the high-pressure, superheated, compound, condensing, semi-stationary type, to 

 direct attention to the fact that, although according to test results it would 

 r.ppear that suction-gas plants are threatened by a competitor which offers equal 

 economy of operation, there are claims of a negative kind which must incline the 

 balance of advantages in the favour of the gas power-plant, at all events for 

 moderate powers. 



3. The Dksel Oil-Engine. By Chas. Day. 



The paper opened with arguments against the selection of an engine being 

 made on makers' guarantees of fuel consumption, as such guarantees cannot pos- 

 sibly cover all working conditions, making it quite possible for the engine which 



VoLL/rres 



Diagram of Carnot Cycle. 



gives the best results on tests to give inferior results over a long period in normal 

 service, when items such as wages, repairs, and maintenance are included. It was 

 urged that the judgment must be based on records of actual working results 

 which include all items of expenditure, and it was pointed out that, owing to 

 the power costs of electricity supply-stations being kept on a uniform basis, and 



