66 DESCRIPTION ora 
be raked off and returned into the vafe when you would 
burn them. Then fee that all the fliding plates are in their 
places and clofe fhut, that no air may enter the ftove but 
through the round opening at the top of the vafe. And 
to avoid the inconvenience of duft from the afhes, let the 
afh-drawer be taken out of the room to be emptied ; and 
when you rake the paflages, do it when the draft of the 
air is {trong inwards, and put the afhes carefully into the 
afh-box, that remaining in its place. 
If being about to go abroad, you would prevent your 
fire burning in your abfence, you may do it by taking the 
brafs flame from the top of the vafe, and covering the 
paflage with a round tin plate, which will prevent the en- 
try of more air than barely fufficient to keep a few of the 
coals alive. When you return, though fome hours abfent, 
by taking off the tin plate and admitting the air, your fire 
will foon be recovered. 
The effect of this machine, well managed, is to burn 
not only the coals, but all the fmoke of the coals, fo that 
while the fire is burning, if you go out and obferve the 
top of your chimney, you will fee no fmoke iffuing, nor 
any thing but clear warm air, which as ufual makes the 
bodies feen through it appear waving. 
But let none imagine from this, that it may be a cure’ 
for bad or {moky chimneys, much lefs, that as it burns 
the fmoke it may be ufed in a room that has no chimney.’ 
’Tis by the help of a good chimney, the higher the better, 
that it produces its effect; and though a flue of plate iron 
fufficiently high might be raifed in a very lofty room, the 
management to prevent all difagreeable vapour would be 
too nice for common practice, and {mall errors would have’ 
unpleafing confequences. 
It is certain that clean iron yields no offenfive fmell 
when heated. Whatever of that kind you perceive, where 
there are iron ftoves, proceeds therefore from fome foul- 
nefs burning or fuming on their furface. They fhould 
therefore 
