THE SMOKE ABATEMENT EXHIBITION. 
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exclusion of others, there are many which, if adopted, would 
materially tend to lessen the evil of smoke. 
A large number of machines are exhibited which are intended 
to feed the furnace at a uniform rate by mechanical means. 
The simplest and one of the best of these is Knap’s Mechanical 
Stoker. In this the coal passes from the feeding hopper to a 
slowly-rotating crushing and feeding roller. From this it falls on 
an inclined surface, down which it slides in front of a reciproca- 
ting pusher, which sends it on to the bars. . These are alternately 
fixed and moveable, and are driven by the slotted levers on the 
outside of the machine, the ends of which cause the moveable 
bars to move up and down, and also to move backwards and for- 
wards, thereby breaking up the coal and preventing the formation 
of clinker. I'he apparatus is compact, and the parts are very 
simple and therefore little liable to get out of order. During 
some trials made at Muspratt’s Chemical Works at Liverpool, it 
was found that the evaporation was 8-2 lbs. of water per lb. of coal 
with a Root’s boiler, when furnished with one of these stokers, 
as against 7T lbs. when the same boiler was fired by hand. 
In Smith’s Mechanical Stoker the coal is fed from a hopper, 
and the bars move to and fro by gearing, whilst they are also 
made to move up and down ; but the peculiarity of this stoker is 
that the fire bars are made hollow, and kept cool by a jet of 
steam which passes along them and then passes out, increasing 
the draught and therefore the combustion. It is claimed that 
the durability of the bars is much increased by this means. 
In Proctor’s Mechanical Stoker the fuel is sent on to the fire 
by what, practically, is a mechanical shovel. A shovel moves 
about a horizontal axis with a rapid forward motion, and so 
drives the coal before it on to the bars. The shovel is worked 
by a cam, which slowly brings the shovel back, the quick forward 
motion being given by a spring. To prevent the wear of the 
apparatus, the blow produced by the spring as the shovel moves 
