PUMPING WATERS. IO3 



When town gas is used (of the standard quality of 

 630 B.T.U. net heat value) the consumption should 

 not exceed 20 cub. ft. per Brake horse-power per 

 hour at full load, and with suction gas-producers 

 using anthracite the consumption of fuel should be 

 about i Ib. per Brake horse-power per hour in small 

 engines and f in very large ones. When gas coke is 

 used 30 per cent more should be allowed. With these 

 considerations in view then, the prospective buyer 

 will be able to see what class of engine will be most 

 suitable to his requirements. For instance, in one 

 place anthracite may be very expensive and oil com- 

 paratively cheap, in another the saving on fuel in a 

 producer may repay the cost of that producer in a 

 few years. This is the case with engines over 10 

 horse -power which work continuously more or 

 less. 



The following advice should be laid to heart : 

 Never select an engine which is just equal or 

 barely equal to the required duty. Many vendors 

 make a practice of this, involving their customers in 

 certain disappointment and continued trouble. No 

 engine should be subjected to overload, as over- 

 heating and (consequent) premature ignitions are 

 thereby induced, involving the risk of sudden de- 

 structive strains on both cylinder and crank shaft. 



Be careful to define the kind of work the engine is 

 to perform, and how long it is to run without a stop. 

 The usual day's run in most places is 9 to 10 hours, 

 but there is no difficulty in providing for much 

 longer periods of work if it is made known, when the 

 engine is being ordered, what length of unbroken run 

 is desired. 



