i'Ki:sii)i:.\ riAi. aii|)ki;ss — skction a. 21 



onerg}' accuniulatecl in the rotating cartii, all (>[ which exist at 

 [•resent, as far as sources of power are concerned, as mere con- 

 ceptions of the mind. 



The function of man is heconu'ng more and more, in modern 

 industrialism, the director of a machine, and yet man, the earliest 

 l)rime-mover to be put to work, is an internal combustion engine, 

 utilising a great variety of solid and licjuid fuels, having an effi- 

 ciency slightly higher than the ordinary steam-engine, but inferior 

 to the modern gas and oil engine. Such was the conclusion 

 arrived at, after elaborate investigation and consideration of the 

 heat value of foods, by Professors Rarr and McKendrick, of 

 Engineering and Physiology respectively, in my student days at 

 Glasgow University. Man works at his greatest rate when 

 lifting continuously a weight consisting of his own body, and he 

 can then develop about ^ of a horse-power for 10 hours per 

 day. Doing mechanical work, such as turning a windlass, the 

 corres])onding horse-]:)Ower is less than i-ioth. Man is, and always 

 will be, employed as a machine, and frequently, I am afraid, is 

 treated from no other point of view, though he ])ossesses 

 liberty of action denied to the inanimate engine. 



The world's work could not now be carried on without 

 mechanical power. As Dugald Clerk says, " The present civi- 

 lisation of the world rests upon the basis of coal and oil fuel, 

 steam, and internal combustion motive power." 



The first census of total power in the United Kingdom, taken 

 in 1907, the latest available returns, showed that the power of 

 industrial engines was over 10^ million h.p., or nearly i h.p. for 

 every person engaged in industries, the details being shown in 

 Table L 



TABLE L 



Industrial Power of the United Kingdom in 1907. 



II. p. H.p. 



Steam engines — 



Reciprocating 9.1 18,818 



Steam turbines 530,892 



— ^ 9,649,710 



Internal combustion engines 680,177 



Water power 177,907 



Other Power 70,681 



Total capacity of engines 10,578,475 



Road rollers, locomotives, etc. (public 



authorities) 166,897 



Agriculture in 1908 (34,450 steam, gas, 



oil, petrol, and other engines) 213,525 



Estimate — 



Railway locomotives 3,300,000 



Mercantile marine 5,000,000 



Royal Navy in time of war f;,ooo,000 



