78 REPORT—1848. 
The plan thus described has several great advantages, some of which I did 
not at all foresee :—Ist, it requires no coal or labour; 2nd, the blast is better 
heated and more regular ; 3rd, the apparatus is more durable. 
The pipes not being exposed to great and sudden changes of temperature, 
from being sometimes overfired, and at other times neglected, do not wear 
out rapidly ; so well proved is this, that the first stove | erected and set to 
work on the 8th of November 1844, now three years and nine months ago, 
is in good repair; and | even think that a sort of cementation process takes 
place, so that the iron in the pipes becomes gradually so tough as to be nearly 
indestructible, whilst, according to the former plan of stoves, I never had a set 
to last twelve months, and although their construction and treatment may have 
been much improved, it is well known the repairs are still frequent and costly. 
I will now notice some points which have always been felt as probable ob- 
jections to this application by practical men. 
First, as to the probability of the flues becoming choked. The flues, if built 
of fire-brick, and placed not lower than 3 feet from the furnace top, have no 
great tendency to clink, whilst any loose stuff collecting in the mouths can be 
readily removed by a rabble. 
Secondly, as to the stove becoming full of dust, The quantity of dust that 
collects in a stove is not great, and until it accumulates very much is of no 
inconvenience, from there being such a surplus supply of heat at command. 
On the contrary, we think the deposit of dust in the stove rather a protection 
to the pipes, and we have gone on with a stove eighteen months without 
cleaning, which continued to give good hot-blast. 
Thirdly, as to the supposed cooling of the blast during stoppage of the 
furnace. If a furnace stops from any cause, we lower the damper, and the 
stove is so closed in and full of heat, with so little of its surface exposed to 
cooling, that we have the blast hot within a few minutes of starting again ; 
besides, we can always keep the damper up until the stove is in full heat, for 
ordinarily the damper is nearly cluse down on the top of the stack. 
Fourthly, as to the difficulty of obtaining hot-blast in blowing in a furnace. 
As to starting a new furnace and a new stove, we put on a cold-blast load for 
the first day’s melting, after which the stove gets dry and gives us hot-blast 
without further trouble. If the stove be of green masonry, I put a small 
drying fire into the stove at the door, and continue it until the draught acts 
readily through the flues. It happened to me in the first stove I erected that 
the damper was let down until the stove should have dried; the gas from the 
furnace collected until it attained the condensation and temperature requisite 
for explosion, which took place, blowing out the front of the stove. By the 
precaution of leaving the damper up, this cannot happen. 
Fifthly, as to the means of cooling the stove, so as to have access to it. 
The mode in which this is effected is one of the most perfect parts of the 
whole arrangement: each stove has a door in front. If we want to cool 
down a stove so as to enter it, we let down the damper, which stops the 
draught from the furnace, and we open the front door, which admits a draught 
of cold air through the stove and flues into the furnace; we either wholly 
close the damper and open the door, or only partially so, if we think it best to 
reduce the temperature gradually, and we have never done any damage toa 
stove in cooling, which is far from being the case when the fire-bars are taken 
out from an ordinary stove-grate to cool it down; for it is acommon saying that 
the cooling down of a stove tostop a leak, generally produces a dozen fresh ones. 
There is however one point to be attended to, from neglect of which I had 
nearly made shipwreck of the plan. 
Fortunately, I erected the first stove so low down the side of the furnace, 
that the point where the flues entered was much above the cross pipes; and 
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