192 



day or longer, depending upon the latitude in which they are 

 placed. 



The Cairo plant gave sufficient steam to produce 50 b.h.p. for 

 ten hours per day, and had it been located further south it 

 would have given probably 65 b.h.p. 



The absorbers are constructed to withstand all the wind of 

 the tropics, whilst the mirrors are set in spring frames so as 

 to avoid any risk of breakage and can be cleaned by washing 

 with a hose. The power generated by the rays of the sun can 

 be stored so as to keep up the supply of power during the 

 whole of a rainy day or through the night by means of storing- 

 heat in boiling water, and the engine has been designed to 

 work economically on this system, which is in extensive use 

 in America. 



Sun-power plants occupy a large area, but in places where 

 they will be installed in the tropics land is very cheap indeed, 

 and the ground rent cf a sun-power plant will be only a fraction 

 of that of a plant of equivalent size in any of the manufacturing 

 centres of Britain. 



All the materials used in the construction of this plant are 

 of the simplest kind, and therefore the cost of upkeep is very 

 slight. 



There is a large field all over the tropics for s-un-power plants 

 where fuel prices are high and where land at present is not 

 irrigated owing to the excessive cost of fuel and the absence 

 of surface water. Sun-power plants could be built to meet 

 the immediate requirements, and then be added to as the 

 population increases. In this way there will be an enormous 

 saving. 



Sun power, of course, is independent of any combination of 

 capital or labour. Every year coal and oil become more 

 expensive, and as time goes on it will, therefore, be better and 

 better for sun power. 



An area of 143 square miles in the Sahara Desert covered 

 with sun-power plants would furnish as much power as that 

 produced by the whole of the coal and oil supply of the world, 

 and as much heat as would be produced by the combustion 

 of our entire store of coal and oil is thrown to the earth by 

 the sun in three years. 



The lecture was illustrated by means of a cinematograph 

 film showing the plant at Cairo at work. 



[DISCUSSION.] 



The CHAIRMAN : Gentlemen Of all the large number of 

 admirable papers delivered at this Congress within the last 

 three days, I am sure none has attracted greater attention and 



