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EXPLANATION OF THE PLATES. 
PLATE III. 
This plate represents Brunton’s apparatus for feeding furnace-fires by means of 
machinery. The general principles of the method and its advantages have been 
stated, (art. 250.) and it only remains to describe the parts of the figure. The 
apparatus was added to two boilers of Boulton and Watt’s construction. To the 
original boilers A A, two additional boilers B B, are attached, which are prepared 
for the purpose of being over the revolving fire-grate ; the smoke from which 
passes over and under the bridges d d, and round the boilers A A, by the flue C ; 
and D D are the flue-doors. The coals, broken to a proper size, are put into the 
hoppers E E, and fall through the openings F F, and through the top of the 
boiler to the grate. The door H, to examine or repair the fire-place, is attached to 
the boiler by a cement joint. The additional boilers are connected to the main 
boilers by the steam pipes G G. 
To clear the dust away that falls over the edge of the revolving grate, there are 
doors at I I; they also admit a small quantity of air to the burning fuel. The 
axis K of the grate is turned by the pinion and wheel at L, turned by the upright 
shaft N, which receives its motion by the shaft R from the engine. 
The pivot of the shaft N, and of the spindle K, are in the foundation plate M. 
The grate bars are surrounded by fire bricks h, and a thin hoop projects below the 
frame, and moves in sand in a trough /, and prevents air entering by any other 
passage than through between the bars: a scraper attached to the grate, and 
consequently moving with it, keeps the channel i clear of dust. 
To regulate the fire, the chains S S are connected to the damper chains, and 
raise or depress the wedge U by the lever T, and thus increase or diminish the 
supply of coals according to the force of the steam. (See art. 257.) 
The feed pipe O, with its stone float c and balance /, are as in other boilers, (art. 
251.) The gauge-cocks are at Z, the man-hole at a, with an internal valve at b; 
the safety valve is at V, with a pipe Q to convey away the steam ; P is the pipe for 
conveying steam to the engine, with a self-acting stop valve W, to prevent the 
steam passing from one boiler to the other when both are in action; and X Y is a 
lever handle for closing the aperture when only a small supply of steam is 
required. 
The construction will admit of considerable variation ; and its advantages in 
saving fuel, in regularity of action, and in consuming the sooty matter of smoke, 
render it a desirable addition to a large boiler.