306 EXPLANATION OF THE PLATES. 



PLATE LXV. 



SECTION OF LOCOMOTIVE ENGINE, STANHOPE AND TYNE RAILWAY. 



Plate LXV. is a general section of the engine, divested of its internal apparatus of 

 tubes, &c., in order to prevent unnecessary complication, and to explain more clearly 

 the more important divisions of the engine. 



A locomotive engine is thus shewn to consist of three principal divisions ; namely, 

 A, the external fire-box, containing the internal one in which the fuel is placed ; B, 

 the boiler, of a cylindrical form, containing the brass tubes placed longitudinally from 

 the smoke-box end D, to the fire-box end A ; through these tubes the flame cir- 

 culates, thereby distributing a maximum quantity of heated surface to the water. 

 The boiler contains two or more long stays, E E, extending from the internal plate of 

 the smoke-box end to the external plate of the fire-box end ; the use of these stays 

 is for preventing too great a strain upon the tubes by the expansion of the metal. In 

 the earlier engines considerable inconvenience was experienced by the cylinders be- 

 coming primed, in consequence of water and steam coming over together and entering 

 them, occasioned principally by the motion of the engine. This inconvenience has 

 been obviated by the introduction of the chamber or steam-head C, into which the 

 steam rises ; from the interior of this chamber the steam is conducted by a pipe 

 (not shewn) to the cylinders. The relative position of the cylinders, piston, and 

 guide frame, to preserve the parallelism of the piston-rod is shewn, by the references 

 F, G, and H ; I is the connecting rod attached to the crank J ; K the man-hole for 

 ascertaining the state of the fire-box, and as an entrance for the purpose of cleaning 

 the same. The fire-bars L, it will be seen, are so placed that with a short lever 

 they may be unhooked from their position, and the whole of the fire allowed to fall 

 out when no longer required. M is the fire or furnace door. 



PLATE LXVL 



SAFETY VALVES, STANHOPE AND TYNE RAILWAY LOCOMOTIVE ENGINE. 



This Plate contains drawings to a working size of the two kinds of safety valves 

 usually employed upon locomotive engines. Fig. 1 is a longitudinal section of the 

 lever safety valve, with the application of Salter's improved spring balance at- 

 tached instead of a weight. Fig. 2 is an elevation of the back of the balance, on 



