REFERENCES 305 



power. With sufficient air to supply oxygen the hydro- 

 carbons are burned completely to carbon dioxide and water. 

 With insufficient oxygen intermediate products are formed, 

 even carbon, and maximum heat is not developed — hence 

 not maximum power. On the other hand, too much air 

 dilutes the mixture to such an extent that maximum power 

 is not obtained. 



Lubricants for engines are obtained, preferably from crude 

 petroleum, and should be light or heavy depending on the 

 purposes for which they are to be used. In gas engine 

 cylinders where high temperatures exist it is important to 

 use a so-called cylinder oil which will not carbonize or 

 vaporize to any extent. Ordinary engine oil will not answer 

 the purpose. 



REFERENCES 



Hirshfeld and Ulbricht. Gas power. 



Levin. The Modern Gas Engine and the Gas Producer. 

 Redwood. A Treatise on Petroleum, 3d ed., vol. ii. 

 Rogers and Aubert. Industrial Chemistry, Chapter XXIII. 

 Whitman. Gas Engine Principles. 



20 



