the length of the flues.
The mafter brewer having exprefied a wifh that
fome contrivance might be ufed by which the water
might be made to boil a little fooner in the new
Boiler, I made an alteration in its fire-place w r hich
completely anfwered that purpofe.
But
and the Economy of Fuel 127
But befides the defire I had to oblige the mailer
brewer, (who only thought how he could contrive
to finifli as early as poffible his day's work) I had
another, and much more important object in view*
Having had reafon to fufpecl that flues which go
round on the outfide of large Boilers do little more
than prevent the efcape of the heat by their fides
which, with infinitely lefs trouble and lefs ex-
penfe, may be prevented by other means, -I was
defirous of finding out, by a decifive Experiment,
the real amount of the advantages gained by thofe
flues ; or the faving of Fuel which they produce.
And as I was confident that the fiippreffion of the
flue which went round the new Boiler would in-
creafe the draught of the fire-place, and accelerate the
combuftion of the Fuel, I concluded that if my opi
nion was well founded with refpect to the fmall-
nefs of the advantages derived from thefe fids
flues , the increafe of heat arifing from the accelera
tion of the combuftion occafioned by the increafed
draught on doling them up would more than coun
terbalance thelofs of thofe advantages, and the time
employed in heating the water would be found to
be actually lefs than it was before.
The refults of the following Experiments fhow
how far my fufpicions were founded.
Experiment, No. 32.
The flue round the outfide of the new Brewhoufe
Boiler having been clofed up, and two canals
( a and b, Fig. 2 1 .) formed from the end of the two
outfide
128 Of the Management of Fire ^
outfide flues of thofe fituated under the Boiler, by
which two canals (which were both furnifhed with
dampers) the fmoke paffed off from under the
Boiler directly into the chimney ; the Experiment
No. 3 1 . which was made with the fame Boiler be
fore the outfide flues were clofed up, was now re
peated with the utmoft care, in order to afcertain
the effects which the clofing up of thofe flues would
produce. The quantity of water in the Boiler, and
its temperature at the beginning of the Experiment,
were the fame ; the wood ufed as Fuel was taken
from the fame parcel, and it was put into the lire-
place in the fame quantities ', and at the fame intervals
of time ; in fliort, every circumftance was the fame
in the two Experiments, excepting only the altera
tions \vhich had been made in the fire-place. As
the length of the flues through which the flame and
fmoke was obliged to pafs to get into the chimney
had been diminifhed more than half, (or reduced
from 70 to about 30 feet) t he ftrength of the draught
of the fire-place was much increafed, as was evident
not only from the increafed violence of the coxnbuf-
tion of the Fuel, which was very apparent, but alfo
from another circumftance, which I think it my
duty to mention. Before the flue round the Boiler
was clofed, if too much Fuel was put into the fire
place at once, it not only did not burn with a clear
flame, but frequently the fmoke, and fometimes
the flame, came out of the fire-place door, even
when the damper in the chimney was wide open ;
but after this flue was clofed up, it was found to be
hardly
and the Economy of Fuel. 129
hardly poflible to overcharge the fire-place, and
the Fuel always burned with the utmoft vivacity*
I ought to inform my Reader, that though the
entrance into the flue which went round the out-
fide of the Boiler was clofed, and another and a
Ihorter road opened for the flame and fmoke to
pafs off into the chimney, yet the cavity of the
flue remained ; and by means of openings (c. c. c.
c. c. c. Fig. 2 1 . Plate V.) about fix inches fquare
in the brick-work which feparated this old road
(which was now fliut up) from the flues under the
Boiler^ the flame was permitted to pafs into this
cavity, and to fpread itfelf round the outfide of the
Boiler. This contrivance (which I would recom
mend for all Boilers) not only prevents the efcape
of the heat out of the Boiler by its fides, but con
tributes fomething towards heating it ; and as the
openings in the fides of the flues do not fenfibly im
pede the motion of the flame, they can do no
harm.
As the two Experiments, the reralts of which I
am about to compare, were made with thegreateft
care, and as they are on feveral accounts uncom
monly interefling, I fhall place them in a confpicu-
ous point of view.
VOL. ft, S A COMPARATIVE
130
Of the Management of Ftre,
A COMPARATIVE VIEW of TWO EXPERIMENTS
made with a new Brewhoufe Boiler.
The time is reckoned from the beginning of the Expe
riment y and 'was the fame in both Experiments.
Quantity of water in the Boiler 11,368 Ibs.
rian weight.
Fuel put into the
Heat of the water in the
fire-place.
Boiler.
*r' r
Ji line from
the begin
ning of the
Experiment.
Number
of billets.
Quantity
in weight.
Experiment
No. 31,
(outfide flue
Experiment
No. 3 a,
(outfide flue
open).
clofed).
hrs. min.
No.
Ibs.
degrees.
degrees.
_- .
80
100
65*
65*
o 16
4
5
79
82
o 30
40
5
90
94
o 53
40
50
107
no
I 6
40
5
118
122
i 2 3
40
50
130
'35
1 37
40
5o
140
147
1 54
40
5o
*55
1 60
2 9
40
50
165
171
2 24
40
50
175
182
2 39
40
5o
182
191
2 54
40
50
200
_
2 59
boiled
3 7
boiled
Having found by comparing the refults of thefe
two Experiments, that I had loft nothing in refped
to the Economy of Fuel, by Shutting up the outfide
flue of my Boiler, I was now defirous of afcer-
taining how much I had gained in point of time,
or
and the Economy of Fuel.
or how much the increafed draught of the fire-place,
in confequence of its flues being fhortened, en
abled me to abridge the time employed in cauf-
ing the contents of the Boiler to boil, in cafes in
which it fhould be advantageous to expedite that
procefs at the expenfe of a fmall additional quan
tity of Fuel.
By the following Experiment, in which the com-
buftion of the Fuel was made as rapid as poflible
by keeping the fire-place full of wood, and the re-
gifter in the afh-pit door and the damper in the
chimney conftantly quite open, may be feen how
far Ifucceeded in the attainment of that object.
Of the Management of Fire 9
Experiment No. 33.
The Boiler contained 11,368 Ibs. Bavarian
weight of water at the temperature of 47. The
tuel ufed was pine-wood, moderately feafoned, in
billets three feet four inches long, and fplit into
fmall pieces of about i Ib. each, that it might
burn the more rapidly.
This experiment was made the 29th of Novem
ber, 1796, the barometer ftanding at 26 inches 8.7
lines Paris meafure, and Fahrenheit's thermometer
Tempera
Fuel put into the
ture of the
Time.
fire-place.
water in
the copper.
hrs. min.
Ibs.
degrees.
2
IOQ
47
o 14
100
58
o 34
100
88
o 51
IOO
IOO
3 9
100
123
o 25
IOO
144
o 39
JOO
*5*
4 o
IOO
O IO
~
200
o 17
boiled
Time employed 2 17
Wood confumed - 800
In the Experiment No. 32, the fame quantity
of water at the temperature of 65^ 3 was made to
boil in 2 hours 59 minutes, with the confumption
of 625 Ibs. of the fame kind of wood. Had the
water in this Experiment been as cold as it was in
the Experiment No. 33, (namely, at the tempera
ture
and the Economy of Fuel. 133
ture of 47) inftead of 625 Ibs. 705 Ibs. of the
Fuel would have been neceilary ; and the procefs,
inftead of lafting 2 hours and 59 minutes, would
have lafted 3 hours and 22 minutes.
Hence we may conclude, that to abridge i hour
and 5 minutes of 3 hours and 22 minutes in the
procefs of boiling 1 1,368 Ibs. of water, this cannot
be done at a lefs additional expenfe of Fuel than
that of 95 Ibs. of pine-wood j or, to abridge the
time one-third, there muft be an additional expenfe
of about one-eighth more Fuel.
In fome cafes it will be moil profitable to fave
time, in others to economize Fuel ; and it will al
ways be defirable to be able to do either, as circum-r
fiances may render moft expedient,
From a comparifon of the quantities of Fuel con-;
fumed, and confequently of heat generated, in the
fame time, with the quantities of heat aclually com
municated to the water, in the Experiments
No. 32 and No, 33, during this time, an idea may
be formed of the great quantity of heat that may
remain in flame and fmoke after they have patted
many feet in flues under the thin bottom of a Boiler
containing cold water ; and this fhows with how
much difficulty thefe hot vapours part with their
heat, and how important it is to be acquainted with
that fact in order to take rneafures with certainty
for economizing Fuel.
I have been the more particular in my account
of thefe Experiments with large Boilers, as I believe
no experiments of the kind on fo large a fcale have
been yet made \ and as they were all conducted
with
134 Of the Management of Fire,
with care, their refults have intrinfic value inde
pendent of the particular ufes to which I have ap
plied them.
As in the countries where this Eflay is likely to
be moft read, pit-coals are more frequently ufed as
Fuel than wood, it will not only be fatisfadory, but
in many cafes may be really ufeful to my Reader to
know the relative quantities of heat producible
from coals and from wood ; in order to be able to
compare the refults of Experiments in which coals
are ufed as Fuel, with thofe of which I have here
given an account ; or to determine the quantity of
coals neceflary in any procefs which it is known
may be performed with a given quantity of wood.
It was my intention to have made a fet of Exper
iments on purpofe to determine the relative quan
tities of heat producible from all the various kind
of combuftible bodies which are ufed as Fuel ; and
I made preparations for beginning them, but I have
not yet been able to findleifure to attend to the fub-
jeft.
The moft fatisfaclory account I have been able
to procure refpecling the matter in queftion, is one
for which I arn indebted to my friend Mr. KIRWAN.
By this account, which he tells me is founded on
Experiments made by Mr. Lavoifier, it appears,
that equal quantities of water, under equal furfaces,
may be evaporated, and confequently equal heats
produced,
By 403 Ibs. of Coaks T f By 1 7 of Coaks
600 of Pit Coal I r 1 i oof Pit Coal
w\j - wi JL IL v^uai / I 1 u i>i i iL \_-ua*
600 of Charcoal f C m mearure 1 4O of Charcoal
1089 of Oak J L 33 of Oak.
I wifh
and the Economy of Fuel. 135
I wifli I were at liberty to tranfcribe the inge
nious and interefting obfervations which accom
panied this eftimate ; but as they make part of a
work which I underftand is preparing for the
Prefs, I dare not anticipate what Mr. KIR WAN will
himfelf foon lay before the Public.
According to this eftimate it appears, that
1089 Ibs. of oak produces as much heat in its
combuftion as 600 Ibs. of pit-coal. Now, if we
fuppofc that the pine-wood ufed in my Experi
ments is capable of producing as much heat per
pound as oak, and I have reafon to think it does
not afford lefs, from the quantity of pine- wood
ufed in any of my Experiments, it is eafy to afcer-
tain how much coal would have been neceiTary to
generate the fame quantity of heat ; for the weight
of the coal which would be required is, to the
weight of the wood actually confumed, 600 to
1089.
In one of my Experiments (No. 31,) 1 1,368 Ibs.
of water, at the temperature of 65-^-, were made
to boil with 650 Ibs. of pine-wood. As, when the
Experiment was made, the mercury in the baro
meter flood at about 28 Englifh inches, the tem
perature of the water when it boiled was only
209^, confequently its temperature was raifed
(209-1 65-^-) 144 degrees. Had the water been
boiled in London, or in any other place nearly on
a level with the furface of the fea, it muft have
been heated to 2 1 2 to have been made to boil,
confequently
Of the Management of Fire >~
confequently its temperature muft have been raifed
1464. ; and to have done this, inftead of 650 Ibs,
of wood, 66 1 ~ Ibs. would have been required j
(144 is to 146^ as 650 Ibs. to 66 if ibs.)
If pit-coal were ufed inftead of wood, 363^ Ibs*
of that kind of Fuel would have been fufficient ;
for the quantities of different kinds of Fuel required
to perform the fame procefs being inverfely as the
quantities of heat which equal weights of the given
kinds of Fuel are capable of generating, or directly
as the quantities of the kind of Fuel in queftion,
which are required to produce the fame heat, it is
1089 to 6oo ? as 66i~ Ibs. of wood to 363^ Ibs. of
coal, fuppofing the foregoing eftimate to be exacl.
Whether it would be poiTible to caufe fo large a
quantity of water, ( 1 68 1 wine gallons) at the given
temperature, (65^) to boil> with this fmall quan
tity of coal, I leave to thofe who are converfant in
Experiments of this kind to determine.
From the refill t of my 2oth Experiment it ap
peared, that 2o T ~ Ibs. of ice-cold water might be
heated 180 degrees, or made to boil under the
mean preffure of the atmofphere at the level of the
furface of the ocean, with the heat generated in the
combuftion of ilb. of pine* wood* Computing
from the refuit of this Experiment, and from the
relative quantities of heat, producible from pine-
wood, and from pit-coal, it appears that the heat
generated in the combuftion of i Ib. of pit-coal,
would make 36 r 3 - Ibs, of ice-cold water boil.
Hence
and the Economy of Fuel. 137
Hence it appears that pit-coal fliould heat 36
times its weight of water, from the freezing point
to that of boiling ; and as it has been found by
Experiments made with great care by Mr. WATT,
that nearly 5^ times as much heat as is fufficient
to heat any given quantity of ice-cold water to the
boiling point, is required to reduce that fame quan
tity of water, already boiling-hot, to fleam ; accord
ing to this eftimation, the heat generated in the
combuflion of i Ib. of coal mould be fufficient
to reduce very nearly 7 Ibs. of boiling-hot water
to fleam.
How far thefe eftimates agree with the Experi
ments that have been made with fleam-engines, I
know not ; but there feems to be much reafon to
fufpecl that the expenfe of Fuel, in working'
thofe engines, is coniiderably greater than it ought
to be, or than it would be, were the Boilers and
Fire-places conflrucled on the befl principles, and
the Fire properly managed.
In attempts to improve, it is always very defir-
able to know exactly what progrefs has been
made ; to be able to meafure the diflance we
have laid behind us in our advances ; and alfo that
which fliU remains between us and the object in
view. The ground which has been gone over is
cafily meafured ; but to eflimate that which flili
lies before us is frequently much more difficult.
The advances I have made in my attempts to
improve fire-places, for the purpofe of economi
zing Fuel, may be eftimated by the refults of the
VOL. IL T -Experiments
Of ^ e Management of Fire,
Experiments of which I have given an account in
this Eifay ; but it would be fatisfaclory no doubt
to know how much farther it is poflible to pulh the
Economy of FueL
In my 4th Experiment, yfj- Ibs. of water, at the
temperature of 58, were made to boil, at Munich,
with 6 Ibs. of wood. If, from the remit of this
Experiment, we compute the quantity of ice-cold
water which, with the heat generated in the com*
buftion of i Ib. of the Fuel, might be heated 180
degrees, or made to boil, it will turn out to be
only iy Ib. or more exactly i.i i Ib.
According to the refult of the Experiment
No. 20, it appeared, that no lefs than 20^- Ibs*
of ice-cold water might have been made to boil
with the heat generated in the combuftion of i Ib.
of pine-wood.
It appears, therefore, that about eighteen times as
much Fuel, in proportion to the quantity of water
heated, was expended in the Experiment No. 4, as
in that No. 20 j and hence we may conclude with
the utmoft certainty, that of the heat generated, or
which, with proper management, might have been
generated in the combuftion of the Fuel ufed in
the 4th Experiment, lefs than ~ part was em
ployed in heating the water ; the remainder,
amounting to more than f |- of the whole quantity*
being difperfed and loft.
I ventured to give it as my opinion in the begin
ning of this Effay, that " not lefs than feven-eighths
"of the heat generated, or which, with proper ma-
" nagcrnent,
and lie Economy of Fuel. 139
" nagement, might be generated from the Fuel ao
tually confumed, is carried up into the atmofphere
" with the fmoke, and totally loft." I will leave
it to my Reader to judge whether this opinion was
not founded on good and fuffieient grounds.
But though it be proved beyond the poffibility
of a cloubt, that the procefs of heating water was
performed in the 2oth Experiment with about ~
part of the proportion of Fuel which was ac
tually expended in the 4th Experiment, yet nei*
ther of thefe Experiments, nor any deductions that
can be founded on their refults, can give us any
light with refpect to the real lofs of heat, or how
much lefs Fuel would be fuffieient were there no
lofs whatever of heat. The Experiments mow
that the lofs of heat muft have been at leaft eighteen
times greater in one cafe than in the other ; but
they do not afford grounds to form even a probable
conjecture refpecling the amount of the lofs of heat
in the Experiment in which the Economy of Fuel
was carried the fartheft, or the poflibility of any
farther improvements in the construction of fire-
places. I mail, however, by availing myfelf of the
labours of others, and comparing the refults of
their Experiments with mine, endeavour to throw
fome light on this abftrufe fubject.
Doctor CRAWFORD, found, by an Experiment
contrived with much ingenuity, and which appears
to have been executed with the utmoft care, that
the heat generated in the combuftion of 30, grains
' of
Of the Management of Fire,
of charcoal raifed the temperature of 3 1 Ibs. 7 oz.
Troy z= 181,920 grains, of water, I T - degrees of
Fahrenheit's thermometer, when none of the heat
generated wasfuffered to efcape.
But if 30 grains of charcoal are neceffaryto raifethc
temperatureof 1 8 i,92ograins of water i -^degrees,
it would require 3157.9 grains of charcoal to raife
the temperature of the fame quantity of water
1 80 degrees, or from the point of freezing to that
of boiling ; for it is 1.71 to 30 grains, as 180 to
3157.9 grains. Confequently the heat generated
in the combuftion of i lb, of charcoal would be
fufficient to heat 57.608 Ibs. of ice-cold water 180
degrees, or to make it boil ; for 3157.9 grains of
charcoal are to 181,920 grains of water as i lb. of
charcoal to 57.608 Ibs. of water.
From the refults of Mr. LAVOISIER'S Experi
ments it appeared that the 'quantities of heat gener
ated in the combuftion of equal weights of char
coal and dry oak, are as 1089 to 600. Hence we
may conclude, that equal quantities of heat are gen-
crated by i lb. of charcoal and 1.815 Ibs. of oak;
confequently that the heat generated in the com
buftion of i .8 1 5 Ibs. of oak, would heat 57.608 Ibs.
of ice-cold water, or i lb. of oak, 31.74^3. of
ice-cold water 180 degrees, or caufe it to boil;
were no part of the heat generated in the combuftion of
fuel loft.
If now we fuppofe the quantities of heat pro-
ftocible from equal weights of dry oak and of dry
pine*
and the Economy of Fuel.
pine-wood to be equal, (and there is reafon to
believe that this fuppofition cannot be far from the
truth) we can eftimate the real lofs of heat in each
of the two Experiments before mentioned, (No. 4
and No, 20) as alfo in every other cafe in which
the quantity of Fuel confumed, and the effects pro
duced by the heat, are known.
Thus, for inftance, in the 2oth Experiment, as
the effects actually indicated that with that part of
the heat generated in the combuftion of i Ib. of the
Fuel which entered the boiler , 20-^-lbs. of ice-cold
water might have been made to boil ; as by the
.above eftimate it appears that 3 1 ~- Ibs. of ice-
cold water might be made to boil with all the heat
generated in the combuftion of i Ib. of the Fuel
it is evident that about one-third of the heat gene-
20.1
rated was loft ; or 7 of it was faved.
This lofs is certainly not greater than might rea-
fonably have been expected, efpecially when we
coniider all the various caufes which confpire in
producing it ; and I doubt whether the Economy
of Fuel will ever be carried much farther.
In the Experiment No. 4, as the effects pro
duced by the heat which entered the Boiler indi
cated that no more than i.i4lb. of ice-cold water
could have been made to boil with i Ib. of the
Fuel, it appears that in this Experiment only about
-j'-g-th part of the heat generated was faved.
In all the Experiments made on a very large
fcale, with Brewhoufe Boilers, rather more than
ene-halfof the heat generated found its way up the
chimney, and was loft.
142 Of the Management of Fire,
CHAR VI.
A Jhort Account of a Number of Kitchens, public and
private, and Fire-places for various Ufes, 'which
have been coiiftrucled under the Direction of the
Author, in different Places. Of the Kitchen of
the HOUSE of INDUSTRY at MUNICH Of that
of the MILITARY ACADEMY Of that of the
MILITARY MESS-HOUSE That of the FARM
HOUSE, and thofe belonging to the INN in the
ENGLISH GARDEN at MUNICH. Of the Kitch
ens of the Hofpitals of LA PIETA and LA Mi-
SERICORDIA at VERONA. Of a fmall Kitchen
fitted up as a Model in the Houfe of SIR JOHN
SINCLAIR Bart, in LONDON. Of the Kitchen
if the FOUNDLING HOSPITAL in LONDON. Of.
a MILITARY KITCHEN for the Ufe of TROOPS inf.
CAMP. Of a PORTABLE BOILER for the Ufe of
TROOPS" on a MARCH. Of a large BOILER fitted
up as a Model for BLEACHERS at the LINEN-
HALL in DUBLIN. Of a Fire-place for COOK
ING, and at the fame Time WARMING A LARGE
HALL ; and of a PERPETUAL OVEN, both fitted
:ip in the HOUSE ^.INDUSTRY at DUBLIN. Of
the KITCHEN LAUNDRY CHIMNEY FIRE
PLACES COTTAGE FIRE-PLACE and Model
and the Economy cf Fuel* 1 43
tof a LIME-KILN -fitted up In IRELAND In the
Houfe of the DUBLIN SOCIETY.
MY wifli to give the moft complete information
poflible with regard to the grounds on which
the improvements I propofe are founded, has in
duced me to be very particular in my account of
my Experiments, and of the conclufions and prac
tical inferences I have thought myfelf authorifed to
draw from them ; and as thefe inveftigations have
frequently led me into abftrufe philofophical dii-
quiiitions which might not perhaps be very inter-
eft ing to many of my readers, to whom a fimple
account of my Fire-places, with directions for con-
ftructing them, might be really ufeful \ in order
to accommodate readers of all defcriptions, I have
thought it beft to divide my fubjecl:, and to referve
what I have ftill to fay on the mechanical part of
it, the Conilruction of Kitchen Fire-places, for
a feparate Effay. In the mean time, for the in
formation of thofe who may have opportunities of
examining any of the Kitchens, or Fire-places, for
other purpofes, which have already been conftrucfced
on my principles, under my direction, I have an
nexed the following account of them, and of the
particular merits and imperfections of each of them,
This account, added to what has been laid in the
foregoing Chapters of this EiTay on the Conftruo
tion of Fire-places, will, I flatter myfelf, be found
fufEcient to convey the fulleft information refpecl:-
ing the fubjcct under confideration, and enable
thofe,
144 Qf ib* Management of Ere,
thofe \vho may wifli to adopt the propofed im*
provements, to conflrucl Fire-places of all kinds on
the principles recommended, without any farther
afnihmce.
Thofe who may not have leifure to enter into
thefe fcientific invefligations, and who, notwith-
flanding, may wiih to imitate thefe inventions, will
find all the information they can want in my next
An Account of the Kitchen of the HOUSE of INDUSTRY
at MUNICH in its prefent State*
THE large circular copper boiler (which is fitu-
atcd in a fmall room adjoining to the great Kitch