1007.] 



on Flame in Gas and Petrol Motors. 



499 



what I have described liappens, and the little engine at once rotates 

 rapidly. This method may be applied to evacuate a larger vessel than 

 that shown on the model, by using an intermediate chamber into 

 which the gases blow through from the explosion chamljer. By 

 this method it will be observed although flame forms the real work- 

 ing fluid, yet the actual operating fluid driving the piston of the 

 small engine is atmospheric air. 



Fig. 1. 



A modification of this method, shown in Fig. 2, enables a partial 

 vacnum to be produced without the aid of preliminary explosion. I 

 have here a small engine known as the Loan engine, which is the sole 

 modern survivor of the vacuum method. In it a piston draws in 

 a flame through a valve ; the flame being produced by gas, the valve 

 closes, and the piston continues the expansion of the flame in its 

 cylinder ; the flame cools, and on the return stroke the piston is forced 

 back under atmospheric pressure from without. Here I have the 

 engine. You see the flame at the upper part of the cylinder. 

 On turning the wheel the flame is sucked into the cvlinder, and vou 



^ 2 K 2 



