CHAP, x.] GAS-ENGINES. 515 



are found. But if we consider the use of gas-engines for a limited 

 application that is, for small operations, where the motive force re- 

 quired is not above a few horse-power, they will then be found 

 superior even from a relatively economical point of view. They 

 adapt themselves indeed to all the requirements of stopping and 

 frequent recommencing of work, when the expense stops at the same 

 moment ; while steam-engines, when once lighted and set going, con- 

 sume fuel all the time they are doing no work. From this point of 

 view hot-air and gas-engines have a real interest, and they will render 

 great service if, in addition, as is not unlikely, they receive improve- 

 ments comparable to those that have been made in the steam- 



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