62 



THE APPLICATIONS OF PHYSICAL FORCES. [BOOK i. 



withdrawn ; these valves are all of one size, and flat, so that either 



side may be used, they are 

 retained in position by the 

 set screws c 1 ; A 1 , the delivery 

 air-vessel; the dotted circle T 

 shows the suction inlet ; x, the 

 flange to which the double 

 delivery- outlet with stop-valve 

 is attached ; v, the piston of 

 water-cylinder with its double 

 leather cap-packing to which 

 access is obtained by the cover 

 Z; YY screwed plugs at ends 

 of water- cylinder. 



The novel feature in this 

 engine is the retention of the 

 crank to terminate the stroke, 

 combined with the absence of 

 the fly-wheel ; the crank D is 

 moved over the dead centres 

 by means of the piston M, of 

 the auxiliary cylinder L, com- 

 municating motion by the 

 piston-rod and small slotted 

 cross-head G to the short 

 crank F, which is in one piece 

 with the main crank D, and at 

 nearly right angles to it. 



An engineer, stoker, 

 and two firemen are 

 required for working 

 and applying a steam 

 fire-engine. In travel- 

 ling all ride on the 

 hose-box except the 

 stoker, who rides be- 

 hind to attend to the 



FIG. 42. Section of the horizontal steam fire-engine, showing 



the arrangement of the force-pumps. flYQ. TllO period of 



