594 POPULAR SCIENCE MONTHLY. 



which is a simple diagram of a single cylinder motor. The chamber 

 R contains the gasoline. Air enters this chamber through tube &, as 

 indicated by the arrow, and passes out between the plate c and the sur- 

 face of the gasoline. The float d keeps the plate c in the proper posi- 

 tion regardless of the amount of liquid in the reservoir. The heated 

 gases exhausted from the cylinder pass through the pipe r, and thus 

 heat the gasoline so that it vaporizes freely and the air passing under 

 c becomes charged with the necessary proportion of vapor. The mixed 

 air and vapor enter a valve chamber 8, from which the flow into pipe 

 e is regulated by the movement of handle a. In this chamber there is 

 another valve, operated by an independent handle, and by means of 

 this more air can be admitted into the mixture when desired. Through 

 the pipe e and the valve / the vapor enters chamber Q, which connects 

 with the top of the cylinder. Suppose the shaft is rotating, then the 

 piston will be drawn down from the position in which it is shown and 

 thus a vacuum will tend to form in chamber Q. This action will cause 

 the valve / to open and the mixture of air and vapor will flow into Q 

 until the piston reaches its lowest position and begins to ascend. At 

 this instant the valve / will close, and then the upward movement of the 

 piston will compress the mixture in the chamber Q. When the piston 

 reaches the upper position, after completing the down and up strokes, 

 the lever I and the contact point p will come together, and an electric- 

 current developed in the induction coil M will pass through the wires 

 j and h and produce a spark at i between the ends of the metallic ter- 

 minals passing through the plug of insulating material, which is shown 

 in dark shading. This spark will cause the mixed air and vapor to 

 ignite, producing an explosion that will force the piston down for the 

 second time. On the second upward movement of the piston the gases 

 produced by the combustion of the vapor will be forced out through 

 the valve h into the chamber T and the pipe r. The valve h and the 

 lever I are operated by cams mounted on the shaft m, and they are so 

 set that the spark at i occurs when the chamber Q is full of the explo- 

 sive mixture and the piston is at the top of the cylinder. The valve 

 opens when the piston begins to move upward after the explosion has 

 forced it to the bottom position. 



As will be seen, the piston must move down to draw in a supply of 

 the explosive mixture; it then moves upward to compress it, and on 

 the second down stroke it is pushed by the force of the explosion. 

 From this action it can be clearly realized that the power developed by 

 the motor comes from the force exerted by explosions at every alter- 

 nate revolution of the shaft. On that account the cams that move the 

 valve h and the lever I are placed on a separate shaft, which is geared 

 to the main shaft in the ratio of two to one; that is, the wheel K is 

 twice the diameter of the wheel J. As the force of the piston acts on 



