GAS, OIL AND ALCOHOL ENGINES 435 



Engines may be designed to use a heavier kerosene oil, 

 and also alcohol. By the addition of a gas producer, 

 power may be obtained from coal by the use of a gas 

 engine. The internal-combustion engine is the most ef- 

 ficient of all engines ; that is, a larger per cent of the 

 heat is converted into mechanical energy than by any 

 other form of prime mover. The efficiency of a steam 

 plant is seldom more than 12 per cent ; that of a gasoline 

 engine is not far from 20 per cent. Alcohol works about 

 as well in the gasoline engine as gasoline. The only 

 difficulty to be had is in starting, as alcohol does not 

 carburet as easily as gasoline. As a rough estimate, four 

 gallons of alcohol are equal to three gallons of gasoline. 



Alcohol is now manufactured in Germany at about 18 

 cents a gallon. It is claimed that alcohol can be manu- 

 factured as a by-product of sugar factories for as low 

 as 10 cents a gallon. Thus we can feel sure that if gaso- 

 line ever becomes so scarce and expensive as to prevent 

 its use upon the farm, we may substitute for it a fuel 

 which may be produced upon the farm itself. 



There is a marked advantage in the use of alcohol in 

 that higher compression pressure may be used without 

 pre-ignition. This tends to increase the efficiency of the 

 engine. It is thought that the time will come when every 

 farm will be provided with a power plant in which an 

 engine of the internal-combustion type will be installed. 



