88 
POLMAISE SYSTEM OF HEATING. 
heated carboniferous air and the wet blanket, is sufficient to 
purify the former of all its injurious particles (its possession of 
which no one denies), is one which I entirely repudiate; or even 
if we admit that it has the power of removing some of the 
poisonous qualities,—would it not be every way preferable to 
make the caloric filter as it were through a quantity of water, 
that it may he made quite pure before it is allowed to mingle 
with the atmosphere of the erection? Yes, it is answered; un¬ 
doubtedly it would purify it to an extent sufficient for all prac¬ 
tical purposes. Then I rejoin, if water is still required, even for 
the Polmaise system, let us have it in the more simple, effective, 
and durable form of a tank. 
At the very outset of the thing, there is a fatal error in the 
situation selected for the stove, necessary, however, from the 
cumbrous nature of the apparatus ; it is placed at the back of the 
erection; thus causing the action to be diametrically opposed to 
one of the first laws of nature which govern the distribution of 
radiated heat; the rapid motion of the particles of this body to 
the highest attainable point the moment they are free, is well 
known; and in the construction of all other means, having for 
their end the equalizing of temperature, advantage has been 
taken of this rule, by causing the calorific air to pass over as 
much space as possible in its passage to the top of the house. 
Here, on the contrary, in the original, the moment it is given off 
the particles mount perpendicularly upward, and of course re¬ 
main there as long as there is the slightest difference in their 
density and that of the air at the lower part of the house; to 
talk of the equal spread of heat attainable from an apparatus of 
this nature is absurd, it cannot happen till this great natural law 
is removed. Then, to remedy some of the most glaring defects, 
comes all the paraphernalia of conducting chambers (it would 
not be new to call them flues), purifying tanks of water, flannel 
tubes, and a host of other improvements , which if adopted would 
place the proprietor in possession of a most complicated imitation 
of the old smoke flues, and nothing more. 
As a last recommendation, the cheapness of the method in ques¬ 
tion is urged ; but the old axiom of “ once well done is twice 
done” should be thought of; for if in effect this, or any other 
system, fall short of the required power it would be dear at any 
