G.— ENGINEERING. 165 



possible use of power. Hence the growing importance of having available 

 an adequate and cheap supply of power produced with the greatest 

 economy of fuel.' 



Mr. D. Brownlie, in papers published in * Engineering ' in 1918-1920, 

 recorded a survey made by him of the steam-raising plant in this country, 

 and an analysis of the statistics collected by him showed that the coal 

 used for the generation of steam in Great Britain for heat and power 

 purposes at that time was between 75 and 100 million tons a year. He 

 showed that the then existing boiler installations could be divided into 

 three classes — bad, average, and highly efficient. The respective per- 

 centages were 10 per cent, bad, 85 per cent, average, and 5 per cent, highly 

 efficient. It is clear, therefore, that there is scope for enormous economies, 

 and, as practice is tending more and more to centralise, much of the power 

 now provided locally by independent plants, 95 per cent, of which are 

 only of average efficiency, including some which are really bad, will be 

 gradually replaced by power electrically transmitted from central sources 

 of generation. As the late Sir George Beilby said : ' The problem of the 

 future which awaits solution is how to stimulate the practical interest of 

 owners of steam-raising plant throughout the country. It may be that 

 the permanently increased cost of coal will supply the necessary stimulus.' 

 In the Coal Conservation Committee's Report (Appendix A) the estimated 

 coal consumption for industries, excluding public utility plants, was 

 given as 66,000,000 tons, made up as follows : — 



Mining, 18,000,000 tons. 



Iron and steel, engineering, textiles, chemicals, paper, and all other 

 trades, 48,000,000 tons. 



In the 1924 coal returns the coal-mines consumed 16.2 million ton,s, 

 while general manufactures and all other purposes consumed 68.5 million 

 tons, a total of 84.7 millions. It will be observed that the coal-mines have 

 dropped their consumption, due no doubt to the installation of modern 

 electrical machinery, such as we know that some of them possess. 



Some of this coal is required for heating purposes by the textile trades, 

 or in brewing, chemical trades, brick-making, bakeries, and so forth. If 

 we deduct 25 per cent, for that purpose from the 68.5 millions, there remain 

 51.4 millions plus 16.2 millions used by coal-mines, or a total of 67.6 million 

 tons of coal for which electrical power could be substituted. 



Owing to the prevalence at that time of iiidifierently efficient steam- 

 raising and power plant, it was stated in the Appendix to the Coal Con- 

 servation Report that approximately 8.03 lb. of coal per horse-power 

 hour were consumed, which, if true, represented an appalling waste, being 

 equivalent to no less than 10.76 lb. per kw.h. or electrical unit. 



While so high a figure as 8.03 lb. may have been recorded at the time 

 of the last Census of Production in 1907, advance must assuredly have 

 been made in recent years. Making some allowance for this advance 

 (though necessarily not too liberal an allowance having regard to Mr. 

 Brownlie's figures for 1918-1920), we may reasonably assume a reduction 

 from 8.03 lb. to 6 lb. per horse-power hour, which is equivalent to 8 lb. 

 per electrical unit. From this it may be directly deduced that if all these 

 power requirements could be supplied, as in all probability some day they 



