The boiler is of the vertical fire-tube type. It consists of 

 a cylindrical drum, formed by upper and lower tube plates, 

 and a shell plate strengthened by windings of steel piano 

 wire to resist bursting. The tube plates are connected by 

 about 300 copper fire tubes. The heating surface of the 

 boiler consists of about 100 square inches of tube plate sur- 

 face and over 4,000 square inches of tube surface, a total of 

 about 30 square feet. Below the lower tube plate is the 

 fire box, which contains the burner. The smoke box and 

 drum of the boiler are thickly lagged with asbestos. 



The water supply for the boiler was contained in a 

 horseshoe-shaped tank of about 15 gallons capacity. The 

 supply, drawn from the bottom of the tank, flowed to a 

 feed pump attached to the engine frame and operated by a 

 rocking lever from one of the engine's cross heads. The 

 water entered the boiler at the lower tube plate, the water 

 level in the boiler being indicated by a gauge glass placed 

 on the right side of the carriage body. A small mirror 

 near the brake pedal enabled the driver to see the glass 

 readily. 



The boiler was normally worked at 150 pounds pressure, 

 as indicated by the pressure gauge at the driver's right foot. 



The gasoline supply for the burner was contained in the 

 cylindrical tank suspended from the frame below the floor- 

 board of the body, air pressure being employed to main- 

 tain the supply. The air pressure was indicated by 

 another pressure gauge on the footboard. 



The engine is of the vertical, double-acting type having 

 two cylinders each 2V / 2 inches in bore and 3V2 inches in 

 stroke. The cranks are set at 90° to each other. The 

 normal speed of the engine was about 400 revolutions per 

 minute. The cylinders and steam chest are thickly lagged 

 with asbestos. Figure 50 shows an engine of almost iden- 

 tical design. 



Ab >ut 3 brake horsepower was developed with a cut-off 

 giving a mean pressure of about 50 pounds. With no cut- 

 off, and with maximum steam pressure, about 10 to 12 

 brake horsepower could be developed for short periods. 

 For its day this was a fairly high horsepower-to-weight 

 ratio, as the car weighs only about 700 pounds. For this 



66 



