SOME COMMON MECHANICAL MOTORS 575 



gasoline, crude petroleum, and gas produced from coal, 

 either as producer gas (Art. 119) or as a waste product from 

 blast furnaces, have become of great importance. 



689. The Gasoline Engine and the Automobile. Many 

 attempts have been made during the past two centuries to 

 produce self-propelled vehicles adapted to use on public 

 streets and country roads (Fig. 361). Until the gasoline 

 engine was perfected but little progress was made in this 



FIG. 361. Cugnot's steam carriage, 1769. (From Stories of Useful Inventions. 

 By Courtesy of the Century Company.) 



direction. The ordinary steam engine was found to be too 

 heavy and cumbersome to be easily adapted to this use. 

 The modern gasoline engine for use in automobiles weighs but 

 about 10 or 15 Ib. to the horse-power; moreover, it is ready for 

 use at all times and can be started at a moment's notice. 

 The chief advantages, then, of the gasoline engine for this 

 purpose are its comparative lightness and the fact that no 

 time need be lost in heating it ready for service. 



690. Gasoline Motors and Aeroplanes. For many centuries 

 men have looked forward to the day when they should be 



