4 i4 



POPULAR SCIENCE MONTHLY. 



Fig. 12 shows more fully the arrangement and location of the machinery. 

 The engine used in these vehicles is made with four cylinders of the 

 single action type; that is, they take steam at one end only. By using 

 this construction, while the number of cylinders is increased, the other 

 parts are greatly simplified, as the piston rods, crossheads and guides 

 can he dispensed with. In addition, the whole engine can be made 

 very compact. 



The boiler is of the flash type; that is, it carries no water ordinarily, 

 but when the engine is in operation, a pump injects into the boiler at 

 each stroke of the engine as much water as may be required to generate 

 the steam necessary -to propel the vehicle; the instant the water enters 

 the boiler it is converted into steam. As the amount of steam is 

 proportional to the amount of water, it can be seen that by regulating 

 the water supply, the power of the engine and thereby the speed of the 



Fig. 13. Showing Details of the Boiler or the Ski:i-oi.i.et Oakkiai; 



carriage, can be controlled. This is the method actually employed to 

 control the speed. In starting, a handle is moved which connects the 

 engine, the boiler and the pump in the proper relation; and while under 

 way the velocity is varied by the manipulation of a lever which controls 

 the amount of water injected into the boiler. The fuel used is kero- 

 sene, which is vaporized and then fed into a properly constructed 

 burner. The amount of oil supplied to the burner is regulated by the 

 same lever that regulates the supply of water, so that both are in- 

 creased or reduced in the proper proportion. The boiler is constructed 

 of a number of steel tubes, which are about two and a half inches in 

 diameter, and from three eighths to half an inch thick. These tubes 

 are pressed into the form shown in Fig. 13, the dark line in the section 

 marked A representing the interior space. A number of tubes col- 

 lapsed in this form and bent into the shape B, are assembled as shown 



