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Account of American Editions of Fo-
reign Publications.
Art. XIII.
Essays, Political, Economical, and
Philosophical. By Benjamin Count
Rumford. The first American,
from the third London Edition.
(Continued from page 305.)
THE fourth essay in this work
is designed to investigate the
causes of defects in the present mode
of constructing chimnies, and to
point out the remedy. The chief
of these defects is the insufficient
or obstructed conveyance of the
smoke; in consequence of which,
that which should pass up the chim-
ney escapes into the room, and
greatly diminishes the comforts and
benefits of fire. For this, the obvi-
ous remedy consists in removing
those hindrances to the ascent of
smoke, whose natural tendency is
upward, and which requires nothing
but a passage.
These hindrances are various;
but, in most cases, the evil is com-
pletely removed merely by dimi-
nishing the fire-place and throat of
the chimney. For this end, a few
bricks, and some mortar, will suf-
fice, and the benefit derived will be,
not only the freeing our apartments
from smoke, so injurious to our
eyes and constitution, and to fur-
niture, and walls, and hangings,
and pictures, but the saving of fuel,
and the promotion of health. One
half, or one third of the fuel for-
merly consumed, will diffuse the
same degree of warmth: this warmth
will be equally diffused, and venti-
lation may be easily effected by
opening, for one or two minutes, a
door or window.
The throats of chimnies are made
too large, chiefly, to afford a passage
to the chimney-sweeper; but there
is a mode to be afterwards explain-
ed, by which this end may be ac-
―377―
complished, consistently with the
reduction of the chimney to just di-
mensions.
Not only the dimensions, but
the place and distance from the fuel,
of the throat or canal of the chim-
ney, ought to be considered. Its
place ought to be perpendicularly
over the fire, and as near the fire as the
situation of the mantle, or arch of
the fire-place, will admit. It may
be sometimes necessary to lower
this arch, which is cheaply and ea-
sily effected by a board or tin plate
stretched across, or a row of bricks,
sustained by an iron bar.
A knowledge of the modes and
operations of heat, may be gained,
in some sort, theoretically; and this,
alone, would point out the due
management of brick, mortar, and
fuel, so as to produce the utmost
quantity of heat. The knowledge,
however, flowing from experiment,
is more satisfactory, and the facts
contained in this essay, though
conformable to, and necessarily
flowing from the known laws of
heat, are, likewise, the direct re-
sults of numerous experiments.
The greatest heat is drawn into
the room by bringing the fire as
far forward as possible. At present
the backs of fire-places are com-
monly as wide as the opening in
front, whereas they ought to be
narrower by one third. The sides
are commonly perpendicular to the
back, and parallel to each other,
whereas they ought to be consider-
ably inclined to it (in an angle of
about one hundred and thirty-five
degrees) and to present an oblique
front towards the opening of the
chimney, in consequence of which,
the heat, instead of being reflected
from one side to the other, is indi-
rectly reflected into the room.
The heat from a fire, being
chiefly produced by reflection from
the back and sides, and this reflec-
tion depending not only on the
position and dimensions of these,
but on the materials of which they
consist, it is of great moment to
discover by what materials the
greatest quantity of heat is reflected.
That which is not reflected is ab-
sorbed. That substance which, by
exposure to the fire, becomes soon-
est and most hot, may be deemed
to absorb most, and, consequently,
to be least suitable to fire-places.
Iron, and metals in general, as
they grow soonest and in the great-
est degree hot, by exposure to burn-
ing fuel; that is, as they absorb
most and reflect least of the heat
imparted by the fuel, are the worst
materials for a fire-place. Com-
mon brick, faced with mortar, is
found to absorb least and reflect
most, and, consequently, is the best
material. Since white surfaces re-
flect more than surfaces of any other
colour, it is useful to white-wash
the sides and back as frequently as
possible.
The degree in which it is proper
to narrow the throat and back of a
chimney, and to bring forward the
fire, is settled by numerous experi-
ments. In fire-places of the com-
mon size, four inches is the proper
width. In no case ought it to ex-
ceed five. The back should be
brought, as nearly as circumstances
will admit, to one third of the
breadth of the opening in front.
The fuel should be perpendicularly
under the opening for the smoke;
and, for that end, the back should
be upright. In the structure of
new, and the amendment of old fire-
places, let the following dimensions
be observed:
- Thickness of the chimney wall, in front, 9 inches.
- Width of the canal or throat, 4
- Depth of the fire-place, 13
- Width of the back, 13
- Obliquity of the sides, 135 degrees.
Passage for the chimney-sweeper
may be provided by placing a mov-
able stone in the new back of the
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chimney, fitted accurately to the
cavity, and capable of being re-
moved and replaced at pleasure.
To confer accuracy upon his
statements respecting the causes and
cure of smoking chimnies, the au-
thor explains, in a diffuse and popu-
lar manner, the cause of the ascent
of smoke. For this end, he ex-
plains the influence of heat, in ex-
panding, making specifically light-
er, and, by consequence, raising
higher, fluids of all kinds. Some
beautiful experiments are describ-
ed, in which oil is made to rise
above water, and hot coloured water
above colourless and cold water.
“Various mechanical contrivan-
ces have been imagined for pre-
venting the wind from blowing
down chimnies, and many of them
have been found to be useful;—
there are, however, many of these
inventions, which, though they pre-
vent the wind from blowing down
the chimney, are so ill-contrived on
other accounts as to obstruct the
ascent of the smoke, and do more
harm than good.
“Of this kind are all those chim-
ney-pots with flat horizontal plates
or roofs placed upon supporters just
above the opening of the pot;—
and most of the caps which turn
with the wind are not much better.
—One of the most simple contri-
vances that can be made use of, and
which, in most cases, will be found
to answer the purpose intended as
well or better than more compli-
cated machinery, is to cover the
top of the chimney with a hollow
truncated pyramid or cone, the di-
ameter of which above, or opening
for the passage of the smoke, is not
above 10 or 11 inches. This pyra-
mid, or cone, (for either will an-
swer) should be of earthen ware,
or of cast iron;—its perpendicular
height may be equal to the diame-
ter of its opening above, and the
diameter of its opening below equal
to three times it height. It should
be placed upon the top of the chim-
ney, and it may be contrived so as
to make a handsome finish to the
brick-work. Where several flews
come out near each other, or in the
same stack of chimnies, the form
of a pyramid will be better than that
of a cone for these covers.
“The intention of this contri-
vance is, that the winds and eddies
which strike against the oblique sur-
face of these covers may be reflected
upwards instead of blowing down
the chimney. The invention is by
no means new, but it has not hi-
therto been often put in practice.
As often as I have seen it tried it
has been found to be of use; I can-
not say, however, that I was ever
obliged to have recourse to it, or to
any similar contrivance; and if I
forbear to enlarge upon the subject
of these inventions, it is because I
am persuaded, that when chimnies
are properly constructed in the neigh-
bourhood of the fire-place, little more
will be necessary to be done at the
top of the chimney than to leave it
open.”
Count Rumford's mode of com-
position is not less singular and
peculiar to himself than the sub-
jects he has chosen. His style is
remarkably diffuse, and his sen-
tences intricate and prolix, yet there
is no want of perspicuity, and no-
thing is languid or monotonous.
The same fact is stated in company
with all its circumstances, and is
stated several times. His conclu-
sions are enforced by the most fa-
miliar, long drawn, and varied il-
lustrations. In this he thinks him-
self justified by that useful purpose
at which he aims, the instruction
of those whose ignorance makes
them slow to apprehend, and their
prejudice reluctant to admit, new
and uncommon truths. Those ac-
customed to reason and investigate,
would be satisfied with greater bre-
vity, but will not be displeased with
that copious display and ample elu-
―379―
cidation of the subject, which, to
minds less active and enlightened,
will prove absolutely necessary.
Several plates accompany this
essay, in which, the author's im-
provements, so successfully unfold-
ed in words, are likewise exhibited
to the eye. Of these, it is only re-
quisite to say, that they fully answer
the end designed by them.
This essay concludes with some
curious remarks upon the manage-
ment of coal fires. As coal is like-
ly to grow, daily, into more exten-
sive use among us, as these remarks
are less diffuse than the preceding
observations, and will afford a fa-
vourable specimen of the compo-
sition of the work, we shall give
them, with little variation, in his
own words.
“I cannot conlude this essay
without again recommending, in
the strongest manner, a careful at-
tention to the management of fires
in open chimnies; for not only the
quantity of heat produced in the
combustion of fuel depends much
on the manner in which the fire is
managed, but even of the heat ac-
tually generated a very small part
only will be saved, or usefully em-
ployed, when the fire is made in a
careless and slovenly manner.
“In lighting a coal fire more wood
should be employed than is com-
monly used, and fewer coals; and as
soon as the fire burns bright, and the
coals are well lighted, and not before,
more coals should be added to in-
crease the fire to its proper size.
“Kindling balls composed of
equal parts of coal—charcoal—and
clay; the two former reduced to a
fine powder, well mixed and knead-
ed together with the clay, moistened
with water, and then formed into
balls of the size of hens’ eggs, and
thoroughly dried, might be used
with great advantage instead of wood
for kindling fires. These kindling
balls may be made so inflammable
as to take fire in an instant and with
the smallest spark, by dipping them
in a strong solution of nitre and
then drying them again, and they
would neither be expensive nor
liable to be spoiled by long keep-
ing. Perhaps a quantity of pure
charcoal, reduced to a very fine
powder, and mixed with the solu-
tion of nitre in which they are dip-
ped, would render them still more
inflammable.
“I have often wondered that no
attempts have been made to im-
prove the fires which are made in
the open chimnies of elegant apart-
ments, by preparing the fuel; for
nothing surely was ever more dirty
and disgusting than a common coal
fire.
“Fire balls of the size of goose
eggs, composed of coal and char-
coal in powder, mixed up with a
due proportion of wet clay, and well
dried, would make a much more
cleanly, and, in all respects, a plea-
santer fire than can be made with
crude coals; and, I believe, would
not be more expensive fuel. In
Flanders, and in several parts of
Germany, and particularly in the
Dutchies of Juliers and Berg,
where coals are used as fuel, the
coals are always prepared before
they are used, by pounding them
to a powder, and mixing them up
with an equal weight of clay, and a
sufficient quantity of water to form
the whole into a mass, which is
kneaded together, and formed into
cakes; which cakes are afterwards
well dried, and kept in a dry place
for use. And it has been found by
long experience, that the expense
attending this preparation is amply
repaid by the improvement of the
fuel. The coals, thus mixed with
clay, not only burn longer, but give
much more heat than when they are
burnt in their crude state.
“It will doubtless appear extra-
ordinary to those who have not
considered the subject with some
attention, that the quantity of heat
―380―
produced in the combustion of any
given quantity of coals should be
increased by mixing the coals with
clay, which is certainly an incom-
bustible body;—but the phenome-
non may, I think, be explained in
a satisfactory manner.
“The heat generated in the com-
bustion of any small particle of coal
existing under two distinct forms,
namely, in that which is combined
with the flame and smoke which
rise from the fire, and which, if
means are not found to stop it, goes
off immediately by the chimney, and
is lost,—and the radiant heat which
is sent off from the fire, in all di-
rections, in right lines;—I think it
reasonable to conclude, that the
particles of clay which are sur-
rounded on all sides by the flame,
arrest a part, at least, of the com-
bined heat, and prevent its escape;
and this combined heat so arrested,
heating the clay red hot, is retained
in it, and being changed by this
operation to radiant heat, is after-
wards emitted, and may be direct-
ed and employed to useful pur-
poses.
“In composing fire balls, I think
it probable that a certain propor-
tion of chaff—of straw cut very
fine, or even of saw-dust, might be
employed with great advantage. I
wish those who have leisure would
turn their thoughts to this subject,
for I am persuaded that very im-
portant improvements would result
from a thorough investigation of
it.
“The enormous waste of fuel
in London may be estimated by
the vast dark cloud which continu-
ally hangs over that great metro-
polis, and frequently overshadows
the whole country, far and wide;
for this dense cloud is certainly
composed almost entirely of uncon-
sumed coal, which, having stolen
wings from the innumerable fires
below, has escaped by the chimnies,
and continues to sail about in the
air, till, having lost the heat which
gave it volatility, it falls in a dry
shower of extremely fine black dust
to the ground, obscuring the atmos-
phere in its descent, and frequently
changing the brighest day into more
than Egyptian darkness.
“I never view from a distance,
as I come into town, this black
cloud which hangs over London,
without wishing to be able to com-
pute the immense number of chal-
drons of coals of which it is com-
posed; for could this be ascertained,
I am persuaded so striking a fact
would awaken the curiosity, and
excite the astonishment of all ranks
of the inhabitants; and perhaps turn
their minds to an object of economy
to which they have hitherto paid lit-
tle attention.”
The fifth essay is somewhat mis-
cellaneous. Its topics are curious
in themselves, but not of such rela-
tive importance as to demand an
accurate abridgment. Some ac-
count is given of the Military Aca-
demy at Munich, of the means em-
ployed to improve the breed of
horses in Bavaria, but which, by
reason of the jealousy and obstinacy
of the peasants, failed of success;
and of a scheme for improving the
breed of horned cattle, the issue of
which has been eminently favour-
able. A plan is then explained
for destroying a species of usury
prevalent at Munich; and, lastly,
a project for employing the soldiery,
in time of peace, in making and
repairing the highways. All these
schemes testify the benevolence and
genius of the writer, and show us
the extensive reformation which the
minister of a despotic prince is ca-
pable of effecting.
Subjoined, are several tables ex-
hibiting the management and ex-
penses of the institutions for the
poor, at Munich and Dublin.