364 APPLIED SCIENCE 



engine shaft. When one desires to start the engine he presses 

 the handle towards the right, so as to bring the clutches to- 

 gether and turns the handle in the direction of the hands of a 

 clock. When the engine begins to fire the clutches slip over 

 one another. 



Carbureter. The carbureter (Fig. 183) reduces the liquid 

 fuel to a fine spray and mixes it with sufficient quantity of air 



FIG. 180. Ignition Apparatus for a Gas Engine. The illustration to the left 

 shows the interior with four dry cells and a spark-coil. The illustration to 

 the right shows the waterproof case, switch, and necessary wiring. 



so that it will burn. It consists of two parts a device for 

 regulating the supply of fuel called the float chamber, and a 

 device for controlling the amount of air to be mixed with the 

 liquid spray. 



Silencer. As the products of combustion are given off at 

 high pressure they expand violently and cause a vacuum in 

 the exhaust pipe. The air rushes back with terrific force 

 (15 Ibs. per square inch) causing a loud noise. To overcome 

 this noise, a device called a silencer is fitted to the machine 

 which allows the gas to escape gradually, or reduces it to 

 atmospheric pressure so that the noise becomes a gentle hiss. 



