198 Fuel Economy. (April, 
Results of Tests, fanuary 22, 23, 1874, at Messrs. Lacy’s. 
Pounds of 
Fitine Time. Coals Water Water 
tt in hours. Used. Evaporated. Evaporated 
. per lb. of Coal. 
Cwts. Lbs. Gallons. 
Hand-fired . . I0°5 Feat te 7150 8°42 
Self-feeding . . I0°5 69 26 7700 9°93 
William Young, Brothers, Queen Street, London, show a 
Smoke Preventer with spiral bars, for every description of 
furnaces, grates, and stoves. By means of this apparatus 
the fuel is introduced at the bottom of the fire, under the 
burning coals, and thus the production of smoke is prevented. 
The smoke preventer is composed of spiral bars mounted on 
an axis, which is moved by hand or machinery each time 
coals are required ; in an ordinary fire-grate, there is a small 
trough at the bottom, in which works an axis carrying two 
vanes of fire-bars. The coal is put into the trough, and the 
poker is used, not to poke the fire, but to turn the fire-bars 
round, thus turning the fresh coal under the ignited coals. 
Messrs. Piercy, of Birmingham, exhibit an apparatus 
called a Mechanical Stoker, patented by Dillwyn Smith. It 
is a very ingenious arrangement for feeding the furnace 
mechanically. In front of the fireplace is a cylinder about 
4 feet long and 8 in diameter; up the top of this is a hopper 
which will hold about 5 cwts. of coal. In the cylinder 
revolves two Archimedean screws, one right and one left, 
which carries the coal into chambers, one underneath each 
screw. In these chambers revolve two fans, which throw 
the coal the whole length of the furnace, the quantity of 
coal being regulated by the requirements of the boiler. 
Mr. Sudlow, of Oldham, exhibits a Rotary Engine, the 
advantages of which are as follows:—It obviates the dead 
points or centres of the crank, and consequent ever-varying 
leverage, the steam acting at an uniform distance from the 
centre throughout its entire travel. It also gives an increased 
longitudinal capacity, wherein to expand high pressure 
steam without incurring pressure, asin the case of compound 
engines; also, where necessary, the flywheel can be entirely 
dispensed with. 
Reese and Gledhill show Wright’s Patent Movable Fire- 
Bar. ‘The rapid and complete manner in which they operate 
upon the combustible matters used decreases the formation 
of clinker or slag, by removing the refuse while in a state of 
dust before it has time to cake into a clinker. By their 
peculiar advancing and retiring action, the slag that is formed 
at the extreme back of the surface is brought, with every 
ow are 
