FIRE. 
the secret by which they were contrived 
for a large premium, given either from the 
crown, or raised hy a subscription of pri- 
vate persons. But the scheme meeting 
with no better success than things of this 
nature usually do, he died without making 
the discovery. Two years after this, the 
person, who had his papers, found the 
method, and it was shewn before the King 
of Poland and a great concourse of nobility 
at Dresden, and the secret purchased at a 
very considerable price. Afterwards, the 
same person carried the invention to Paris, 
and many other places, and practised it 
every where with success. The secret 
was this : A wooden vessel was provided, 
bolding a very considerable quantity of 
water : in the centre of this was fixed a 
through the middle of the tunnel, and not 
along the sides. It would be more ad- 
visable to stop, with a wet blanket, the 
upper orifice of the tunnel ; but the surest 
and readiest method is, to apply the blanket 
either to the throat of the chimney; or over 
the whole front of the fire-place. If there 
happens to be a chimney-board or a register, 
nothing can be so effectual as to apply 
them immediately ; and having by that 
means stopped the draught of air from 
below, the burning soot will be put out 
, as readily and as completely as a candle 
is put out by an extinguisher, which acts 
exactly upon the same principle. Mr. 
Smart’s machine for sweeping chimneys is 
admirably adapted to extinguish those 
that are on fire. See Chimney -sweeping. 
case made of iron plates, and filled with 
gun-powder ; from this vessel, to the head 
of the larger vessel containing the water, 
there was conveyed a tube or pipe, which 
might convey the fire very readily through 
the water to the gun powder contained 
in the inner vessel. This tube was filled 
with a preparation easily taking fire, and 
quickly burning away ; and the manner 
of using the thing was, to convey it into the 
room or building where the fire was, with 
the powder in the tube lighted. The con- 
sequence of this was, that the powder in 
the inner case soon took fire, and with 
a great explosion burst the vessel to pieces, 
and dispersed the water every way; thus 
was the tire put out in an instant, though 
the room was flaming before in all parts at 
once. The advantage of this invention 
was, that, at a small expense, and with the 
help of a few people, a fire in its beginning 
might be extinguished ; but tbe thing was not 
so general as it was at first expected that 
it would prove, for though of certain effi- 
cacy in a chamber or close building, where 
a fire had but newly begun, yet when the 
mischief has increased so far that the house 
was fallen in, or the top open, the machine 
had no effect. 
Fire in chimneys, method of extinguish- 
ing. It is well known, that the inner parts 
of chimneys easily take fire ; the soot that 
kindles therein emits a greater flame, ac- 
cording as the tunnel is more elevated, be- 
cause the current of air feeds the fire. If 
this current could therefore be suppressed, 
the fire would soon be extinguished. In 
order to this, some discharge a pistol into 
the chimney, which produces no effect. 
Water thrown into the chimney at the top 
js equally useless, because it comes down 
Fire, securing buildings against. Dr, 
Hales proposes to check the progress of 
fires by covering the floors of the adjoining 
rooms with earth. The proposal is found- 
ed on an experiment which he made with 
a fir board half an inch thick, part of 
which he covered with an inch depth of 
damp garden-mould, and then lighted a 
fire on the surface of the mould; though 
the fire was kept up by blowing, it was 
two hours before the board was burnt 
through, and the earth prevented it from 
flaming. The thicker the earth is laid on 
the floors, the better : however, Dr. Hales 
apprehends that the depth of an inch will 
generally be sufficient : and he recom- 
mends to lay a deeper covering on the 
stairs, because the fire commonly ascends 
by them with the greatest velocity. Mr. 
David Hartley made several trials in the 
years 1775 and 1776, in order to evince 
the efficacy of a method which he had in- 
vented for restraining the spread of fire in 
buildings. For this purpose, thin iron 
plates were well nailed to the tops of the 
joists, &c. the edges of the sides and ends 
being lapped over, folded together, and 
hammered close. Partitions, stairs, and 
floors, may be defended in the same man- 
ner; and plates applied to one side have 
been found sufficient. The plates are sq 
thin as not to prevent the floor from being 
nailed on the joists, in the same manner as 
if this preventive was not used ; they are 
kept from rust by being painted or var- 
nished with oil and turpentine. The ex- 
pense of this addition, when extending 
through a whole building, is reckoned at 
about five per cent. Mr. Hartley had a 
patent for this invention, and parliament 
voted a sum of money towards defraying 
