466 
STEPHENSON’S PATENT 
freely through, which improves the sound considerably. The cock is required to be 
steadily opened to adjust the quantity of steam, so as to produce the clearest sound. 
The steam whistle is very effective, and its sound can be heard at a great distance. 
THE TENDER. 
The tender is attached behind the engine and close to it; it contains a tank of 
water for supplying the boiler, and has a space in the middle filled with coke for 
feeding the fire. A side elevation of it is shewn in Plate LXXXIX., a longi 
tudinal section in Plate XC., and a plan in Plate XCII. 
Framing.—The side frames, A" A", are made double, with diagonal bracing pieces 
inside them, and are connected by strong pieces at the ends. The floor is supported 
by diagonal and cross pieces, dotted in the plan, which are fixed into the sides and 
ends; and the joints of these pieces are strengthened by iron plates; the plate in the 
centre is shewn at x \ extending along each of them. An iron bar, B" B", is fixed upon 
the bottom along the centre, and another bar bolted to it underneath at the front, the 
two projecting beyond the front, and having holes in their ends through which the pin 
X' is passed to connect the socket at the end of the drawing links W' of the engine. 
A chain and hook, y\ is fixed on to the other end of the draw bar B", for the 
purpose of attaching the train of carriages ; in this end of the bar a large square 
socket is made, and is fitted upon the middle of the long spring C". D" D" are the 
uflfers faced with leather cushions, and fixed upon iron spindles which pass through 
holes in the centre of two blocks of wood, z z, that are bolted upon the end of the 
frame; and the spindles have sockets in the outer ends in which the ends of the 
spring C" rest, and when the buffers strike against those of another carriage they 
press against the spring C", which yields and reduces the shock of the collision. 
Wheels.—The tender runs upon four wheels, G" G", three feet diameter, which 
turn in the space between the pieces of the side frames ; they are made with flanches, 
and are similar to the small wheels of the engine. The wheels are keyed upon 
the axles, which are 3^ inches diameter, and turn at their outer extremities in 
axle boxes similar in principle to those of the engine ; the axle guides consist only 
of a single plate, each three quarters of an inch thick, bolted on to the inside of the 
outer pieces of the frame, and the axle boxes have grooves cast in their sides, into 
which the edges of the axle guides are fitted. The springs H" H" are fixed down 
upon the top of the axle boxes by two bolts made each into a large eye at the upper 
end, which fits upon the spring, and the ends of the springs rest in sockets fixed upon 
the under side of the outer piece of the frame. The tenders for the largest engines 
are often placed upon six wheels, to diminish the weight upon each wheel.