1874.! Fuel Economy. 203 
time is lost in waiting to get up steam. The attendance 
required is exceedingly small, averaging one hour per day 
for a man, including cleaning, oiling, stopping, and starting. 
The fuel has not to be got into the house, nor ashes to be 
got out; gas is laid on, thus much trouble is saved. No 
constant supply of water is required ; a quart a day suffices. 
Gas at 4s. per thousand feet will feed the engine at one 
penny an hour per horse-power. Gas can only be burnt in 
exact proportion to the power required; this is controlled by 
a governor. ‘These engines cannot be used for high horse- 
power; from one to two horse-power is the most they can 
be used for. From the many testimonials received, it seems 
that the cost of gas is less than one penny per hour. 
The show of fire-grates, kitchen ranges, various kinds of 
coal savers, is very good, and perhaps the most complete in 
the Exhibition. The grates, &c., are all in use in the third 
annexé of the building, so that spectators can judge for 
themselves as to the relative merits of the various inven- 
tions. What would have made this show still more inte- 
resting would have been to have given the weight of coal 
consumed by each fire during the day to produce the desired 
effect; as it is, one sees an interesting collection of machines 
for saving fuel, but no experiments seem to have been per- 
formed by competent judges to test the truth of each in- 
ventor’s statements. There are various grates for utilising 
the waste heat of the fire and causing it to warm air- 
chambers, which warm air is carried to different rooms in 
the house. 
Shillito and Shorland exhibit patent grates and hot-air 
boxes for extracting waste heat from every description of 
grates and kitchen ranges, thereby effecting a saving of at 
least 50 per cent in fuel, without at all interfering with the 
general appearance of grates. One of their 30s. boxes can 
be inserted behind register or sham register stoves now in 
use, and could also be placed behind a kitchen fire without 
taking down the range or grate, and, according to the 
inventor’s statement, will raise temperature in excess of 
external atmosphere from 10° to 20°, and discharge into 
room or lobby 2000 cubic feet of warm air per hour. The 
advantages of this fire-box grate over the ordinary grate are, 
that it secures a supply of perfectly fresh, warm, pure air, 
and diffuses it equally over the whole room, or rooms 
requiring to be heated, the cold air admitted from the 
outside being perfectly fresh, and warmed by passing over 
the inside back of the grate. The objection to other hot-air 
stoves, that they draw their supply from the already vitiated 
