PRACTICAL BOOK OF GARDEN ARCHITECTURE 



quarts of kerosene, or three pounds of anthracite 

 coal per hour. An engine able to lift ten times as 

 much water to the same height, in the same time, 

 will consume one hundred cubic feet of gas, five 

 quarts of kerosene, or seven to eight pounds of an- 

 thracite coal per hour." 



This gives a fair estimate of cost, which varies 

 but little with other forms of fuel. In some of the 

 old forms of hot-air engines there was difficulty in 

 obtaining the necessary vacuum for raising the water 

 to the required height, when pumping from an 

 artesian well to a tank from forty to fifty feet above 

 the source of supply. To overcome this difficulty, 

 one model is so arranged that the pump itself is 

 placed on a long rod, thus making it possible to 

 operate it much nearer the surface of the water than 

 the usual location of the engine would permit. The 

 usual location, by the way, for the hot-air engine is 

 in the cellar, the barn, or some outbuilding or a 

 small power house. An engine of this sort need not 

 require any attention beyond the supplying of fuel at 

 proper intervals during pumping, it will practically 

 last a life-time with little cost for repairs and is 

 suitable for keeping the water tanks well filled in the 

 most remote country districts. 



When the steam engine is used, as another solu- 

 tion of the water power problem, the working of the 



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