These directions are so clear, that it i_Essays; Political, Economical, and Philosophical

mistake them; and those who follow them exactly will find their

potatoes surprisingly improved, and will be convinced that the

manner of boiling them is a matter of much greater importance

than has hitherto been imagined.

Were this method of boiling potatoes generally known in countries

where these vegetables are only beginning to make their way into

common use,-- as in Bavaria, for instance,--I have no doubt but

it would contribute more than any thing else to their speedy

introduction.

The following account of an experiment, lately made in one of the

parishes of this metropolis (London), was communicated to me by a

friend, who has permitted me to publish it.--It will serve to

show,--what I am most anxious to make appear,-- that the

prejudices of the Poor in regard to their Food ARE NOT

UNCONQUERABLE

February 25th, 1796.

The parish officers of Saint Olaves, Southwark, desirous of

contributing their aid towards lessening the consumption of

wheat, resolved on the following succedaneum for their customary

suet puddings, which they give to their Poor for dinner one day

in the week; which was ordered as follows:

L. s. d.

200 lb. potatoes boiled, and

skinned and mashed ... ... 0 8 0

2 gallons of milk ... ... ... 0 2 4

12 lb. of suet, at 4 1/2 ... 0 4 6

1 peck of flour ... ... ... 0 4 0

Baking ... ... ... ... ... 0 1 8

---------

Expense 1 0 6

---------

Their ordinary suet pudding had been made thus:

2 bushels of flour ... ... ... 1 12 0

12 lb. suet ... ... ... ... 0 4 6

Baking ... ... ... ... ... 0 1 8

---------

Expense 1 18 2

Cost of the ingredients for the

potatoes suet pudding ... ... 1 0 6

---------

Difference 0 17 8

---------

This was the dinner provided for 200 persons, who gave a decided

perference to the cheapest of these preparations, and with it to

be continued.

The following baked potatoe-puddings were prepared in the hotel

where I lodge, and were tasted by a number of persons, who found

them in general very palatable.

Baked Potatoe-puddings.

No. I.

12 ounces of potatoes, boiled, skinned, and mashed;

1 ounce of suet;

1 ounce (or 1/16 of a pint) of milk, and

1 ounce of Gloucester cheese.

Total 15 ounces,--mixed with as much boiling water as was necessary

to bring it to a due consistence, and then baked in an earthen pan.

No. II.

12 ounces of mashed potatoes as before;

1 ounces of milk, and

1 ounce of suet, with a sufficient quantity of salt.--Mixed up

with boiling water, and baked in a pan.

No. III.

12 ounces of mashed potatoes;

1 ounce of suet;

1 ounce of red herrings pounded fine in a mortar.--Mixed--baked,

etc. as before.

No. IV.

12 ounces of mashed potatoes;

1 ounce of suet, and

1 ounce of hung beef grated fine with a grater.--Mixed and baked

as before.

These puddings when baked weighed from 11 to 12 ounces each.--

They were all liked by those who tasted them, but No I and No 3

seemed to meet with the most general approbation.

Receipt for a very cheap Potatoe-dumplin.

Take any quantity of potatoes, half boiled;--skin or pare them,

and grate them to a coarse powder with a grater;--mix them up

with a very small quantity of flour, 1/16, for instance, of the

weight of the potatoes, or even less;--add a seasoning of salt,

pepper, and sweet herbs;--mix up the whole with boiling water to

a proper consistency, and form the mass into dumplins of the size

of a large apple.-- Roll the dumplins, when formed, in flour, to

prevent the water from penetrating them, and put them into

boiling water, and boil them till they rise to the surface of the

water, and swim, when they will be found to be sufficiently done.

These dumplins may be made very savoury by mixing with them a

small quantity of grated hung beef, or of pounded red herring.

Fried bread may likewise be mixed with them, and this without any

other addition, except a seasoning of salt, forms an excellent

dish.

Upon the same principles upon which these dumplins are prepared

large boiled bag-puddings may be made; and for feeding the Poor

in a public establishment, where great numbers are to be fed,

puddings, as these is less trouble in preparing them, are always

to be preferred to dumplins.

It would swell this Essay, (which has already exceeded the limits

assigned to it,) to the size of a large volume, were I to give

receipts for all the good dishes that may be prepared with

potatoes.--There is however one method of preparing potatoes

much in use in many parts of Germany, which appears to me to

deserve being particularly mentioned and recommended;--it is as

follows:

A Receipt for preparing boiled Potatoes with a Sauce.

The potatoes being properly boiled, and skinned, are cut into

slices, and put into a dish, and a sauce, similar to that

commonly used with a fricaseed chicken, is poured over them.

This makes an excellent and a very wholesome dish, but more

calculated, it is true, for the tables of the opulent than for

the Poor.--Good sauces might however be composed for this dish

which would not be expensive.--Common milk-porridge, made rather

thicker than usual, with wheat flour, and well salted, would not

be a bad sauce for it.

Potatoe Salad.

A dish in high repute in some parts of Germany, and which

deserves to be particularly recommended, is a salad of potatoes.

The potatoes being properly boiled and skinned, are cut into thin

slices, and the same sauce which is commonly used for salads of

lettuce is poured over them; some mix anchovies with this sauce,

which gives it a very agreeable relish, and with potatoes it is

remarkably palatable.

Boiled potatoes cut in slices and fried in butter, or in lard,

and seasoned with salt and pepper, is likewise a very palatable

and wholesome dish.

Of Barley.

I have more than once mentioned the extraordinary nutritive

powers of this grain, and the use of it in feeding the Poor

cannot be too strongly recommended.--It is now beginning to be

much used in this country, mixed with wheat flour, for making

bread; but is not, I am persuaded, in bread, but in soups,

that Barley can be employed to the greatest advantage.--It is

astonishing how much water a small quantity of Barley-meal will

thicken, and change to the consistency of a jelly; and, if my

suspicions with regard to the part which water acts in nutrition

are founded, this will enable us to account, not only for the

nutritive quality of Barley, but also for the same quality in a

still higher degree which sago and salope are known to possess.--

Sago and Salope thicken, and change to the consistency of a

jelly, (and as I suppose, prepare for decomposition,) a greater

quantity of water than Barley, and both sago and salope are known

to be nutritious in a very extraordinary degree.

Barley will thicken and change to a jelly much more water than

any other grain with which we are acquainted, rice even not

excepted;--and I have found reason to conclude from the result of

innumerable experiments, which in the course of several years

have been made under my direction in the public kitchen of the

House of Industry at Munich, that for making soups, Barley is by

far the best grain that can be employed.

Were I called upon to give an opinion in regard to the

comparative nutritiousness of Barley-meal and wheat flour,

WHEN USED IN SOUPS I should not hesitate to say that I think the

former at least three or four times as nutritious as the latter.

Scotch broth is known to be one of the most nourishing dishes in

common use; and there is no doubt but it owes its extraordinary

nutritive quality to the Scotch (or Pearl) Barley, which is

always used in preparing it.--If the Barley be omitted, the broth

will be found to be poor and washy, and will afford little

nourishment;--but any of the other ingredients may be retrenched;--

even the meat;-- without impairing very sensibly the nutritive

quality of the Food.--Its flavour and palatableness may be impaired

by such retrenchments; but if the water be well thickened with

the Barley, the Food will still be very nourishing.

In preparing the soup used in feeding the Poor in the House of

Industry at Munich, Pearl Barley has hitherto been used; but I

have found, by some experiments I have lately made in London,

that Pearl Barley is by no means necessary, as common Barley-meal

will answer, to all intents and purposes, just as well.--In one

respect it answers better, for it does not require half so much

boiling.

In comparing cheap soups for feeding the Poor, the following

short and plain directions will be found to be useful:

General Directions for preparing cheap Soup.

First, Each portion of Soup should consist of one pint and a

quarter, which, if the Soup be rich, will afford a good meal to a

grown person.--Such a portion will in general weigh about one

pound and a quarter, or twenty ounces Avoirdupois.

Secondly, The basis of each portion of Soup should consist of one

ounce and a quarter of Barley-meal, boiled with ONE PINT AND A

QUARTER OF WATER till the whole be reduced to the uniform

consistency of a thick jelly.--All other additions to the Soup do

little else than to serve to make it more palatable; or by

rendering a long mastication necessary, to increase and prolong

the pleasure of eating;--both these objects are however of very

great importance, and too much attention cannot be paid to them;

but both of them may, with proper management, be attained without

much expence.

Were I asked to give a Receipt for the cheapest Food which

(in my opinion) it would be possible to provide in this country,

it would be the following:

Receipt for a very cheap Soup.

Take of water eight gallons, and mixing with it 5 lb. of Barley-meal,

boil it to the consistency of a thick jelly.--Season it with

salt, pepper, vinegar, sweet herbs, and four red herrings,

pounded in a mortar.--Instead of bread, add to it 5 lb. of Indian

Corn made into Samp, and stirring it together with a ladle, serve

it up immediately in portions of 20 ounces.

Samp, which is here recommended, is a dish said to have been

invented by the savages of North America, who have no Corn-mills.

--It is Indian Corn deprived of its external coat by soaking it

ten or twelve hours in a lixivium of water and wood-ashes.--

This coat, or husk, being separated from the kernel, rises to the

surface of the water, while the grain, which is specifically

heavier than water, remains at the bottom of the vessel; which

grain, thus deprived of its hard coat of armour, is boiled, or

rather simmered for a great length of time, two days for instance,

in a kettle of water placed near the fire.--When sufficiently

cooked, the kernels will be found to be swelled to a great size

and burst open, and this Food, which is uncommonly sweet and

nourishing, may be used in a great variety of ways; but the best

way of using it is to mix it with milk, and with soups, and broths,

as a substitute for bread. It is even better than bread for

these purposes, for besides being quite as palatable as the very

best bread, as it is less liable than bread to grow too soft when

mixed with these liquids, without being disagreeably hard, it

requires more mastication, and consequently tends more to increase

and prolong the pleasure of eating.

The Soup which may be prepared with the quantities of ingredients

mentioned in the foregoing Receipt will be sufficient for 64

portions, and the cost of these ingredients will be as follows:

Pence.

For 5 lb. of Barley-meal, at 1 1/2 pence, the ]

Barley being reckoned at the present ]

very high price of it in this country, viz ]... 7 1/2

5s. 6d. per bushel ]

5 lb. of Indian Corn, at 1 1/4 pence the pound ... 6 1/4

4 red herrings ... ... ... ... ... ... ... 3

Vinegar... ... ... ... ... ... ... ... ... 1

Salt ... ... ... ... ... ... ... ... ... 1

Pepper and sweet herbs ... ... ... ... ... 2

-------

Total 20 3/4

-------

This sum, (20 3/4 pence,) divided by 64, the number of portions

of Soup, gives something less than ONE THIRD OF A PENNY for the

cost of each portion.--But at the medium price of Barley in Great

Britain, and of Indian Corn as it may be afforded here, I am

persuaded that this Soup may be provided at one farthing the

portion of 20 ounces.

There is another kind of Soup in great repute among the poor

people, and indeed among the opulent farmers, in Germany, which

would not come much higher.--This is what is called burnt Soup,

or as I should rather call it, brown Soup, and it is prepared in

the following manner:

Receipt for making BROWN SOUP.

Take a small piece of butter and put it over the fire in a clean

frying-pan made of iron (not copper, for that metal used for this

purpose would be poisonous);-- put to it a few spoonfuls of wheat

or rye meal;--stir the whole about briskly with a broad wooden

spoon, or rather knife, with a broad and thin edge, till the

butter has disappeared, and the meal is uniformly of a deep brown

colour; great care being taken, by stirring it continually, to

prevent the meal from being burned to the pan.

A very small quantity of this roasted meal, (perhaps half an

ounce in weight would be sufficient,) being put into a sauce-pan

and boiled with a pint and a quarter of water, forms a portion of

Soup, which, when seasoned with salt, pepper, and vinegar, and

eaten with bread cut fine, and mixed with it at the moment when

it is served up, makes a kind of Food by no means unpalatable;

and which is said to be very wholesome.

As this Soup may be prepared in a very short time, an instant

being sufficient for boiling it; and as the ingredients for

making it are very cheap, and may be easily transported,

this Food is much used in Bavaria by our wood-cutters, who go

into the mountains far from any habitations to fell wood.--

Their provisions for a week, (the time they commonly remain in

the mountains,) consist of a large loaf of rye bread (which,

as it does not so soon grow dry and stale as wheaten bread,

is always preferred to it); a linen bag containing a small

quantity of roasted meal;--another small bag of salt;--and a

small wooden box containing some pounded black pepper;--with a

small frying-pan of hammered iron, about ten or eleven inches in

diameter, which serves them both as an utensil for cooking, and

as a dish for containing the victuals when cooked.--They

sometimes, but not often, take with them a small bottle of

vinegar;--but black-pepper is an ingredient in brown Soup which

is never omitted.--Two table-spoonfuls of roasted meal is quite

enough to make a good portion of Soup for one person; and the

quantity of butter necessary to be used in roasting this quantity

of meal is very small, and will cost very little.--One ounce of

butter would be sufficient for roasting eight ounces of meal; and

if half an ounce of roasted meal is sufficient for making one

portion of Soup, the butter will not amount to more than 1/10 of

an ounce; and, at eight pence the pound, will cost only 1/32 of a

penny, or 1/8 of a farthing.--The cost of the meal for a portion

of this Soup is not much more considerable. If it be rye meal,

(which is said to be quite as good for roasting as the finest

wheat flour,) it will not cost, in this country, even now when

grain is so dear, more than 1 1/2d. per pound;-- 1/2 an ounce,

therefore, the quantity required for one portion of the Soup,

would cost only 6/32 of a farthing;--and the meal and butter

together no more than (1/8 + 6/32) = 10/32, or something less

than 1/3 of a farthing.--If to this sum we add the cost of the

ingredients used to season the Soup, namely, for salt, pepper and

vinegar, allowing for them as much as the amount of the cost of

the butter and the meal, or 1/3 of a farthing, this will give 2/3

of a farthing for the cost of the ingredients used in preparing

one portion of this Soup; but as the bread which is eaten with it

is an expensive article, this Food will not, upon the whole,

be cheaper than the Soup just mentioned; and it is certainly

neither so nourishing nor so wholesome.

Brown Soup might, however, on certain occasions, be found to be

useful. As it is so soon cooked, and as the ingredients for

making it are so easily prepared, preserved, and transported from

place to place; it might be useful to travellers, and to soldiers

on a march. And though it can hardly be supposed to be of itself

very nourishing, yet it is possible it may render the bread eaten

with it not only more nutritive, but also more wholesome;-- and

it certainly renders it more savoury and palatable.--It is the

common breakfast of the peasants in Bavaria; and it is infinitely

preferable, in all respects, to that most pernicious wash, TEA,

with which the lower classes of the inhabitants of this island

drench their stomachs, and ruin their constitutions.

When tea is mixed with a sufficient quantity of sugar and good

cream;--when it is taken with a large quantity of bread and

butter, or with toast and boiled eggs;--and above all,--WHEN IT

IS NOT DRANK TOO HOT, it is certainly less unwholesome; but a

simple infusion of this drug, drank boiling hot, as the Poor

usually take it, is certainly a poison which, though it is

sometimes slow in its operation, never fails to produce very

fatal effects, even in the strongest constitution, where the free

use of it is continued for a considerable length of time.

Of Rye Bread

The prejudice in this island against bread made of Rye, is the

more extraordinary, as in many parts of the country no other kind

of bread is used; and as the general use of it in many parts of

Europe, for ages, has proved it to be perfectly wholesome.--

In those countries where it is in common use, many persons

prefer it to bread made of the best wheat flour; and though

wheaten bread is commonly preferred to it, yet I am persuaded

that the general dislike of it, where it is not much in use, is

more owing to its being BADLY PREPARED, or not well baked, than

to any thing else.

As an account of some experiments upon baking Rye Bread, which

were made under my immediate care and inspection in the

bake-house of the House of Industry at Munich, may perhaps be of

use to those who wish to known how good Rye Bread may be prepared;

as also to such as are desirous of ascertaining, by similar

experiments, what, in any given case, the profits of a baker

really are; I shall publish an account in detail of these

experiments, in the Appendix to this volume.

I cannot conclude this Essay, without once more recommending,

in the most earnest manner, to the attention of the Public,

and more especially to the attention of all those who are engaged

in public affairs,--the subject which has here been attempted to

be investigated. It is certainly of very great importance,

in whatever light it is considered; and it is particularly so at

the present moment: for however statesmen may differ in opinion

with respect to the danger or expediency of making any alterations

in the constitution, or established forms of government, in times

of popular commotion, no doubts can be entertained with respect

to the policy of diminishing, as much as possible, at all times,

--and more especially in times like the present,--the misery of

the lower classes of the people.

END OF THE THIRD ESSAY.

Footnotes for Essay III.

[1]

November 1795.

[2]

The preparation of water is, in many cases, an object of more

importance than is generally imagined; particularly when it is

made use of as a vehicle for conveying agreeable tastes.

In making punch, for instance, if the water used be previously

boiled two or three hours with a handful of rice, the punch made

from it will be incomparably better, than is to say, more full

and luscious upon the palate, than when the water is not prepared.

[3]

I cannot dismiss this subject, the feeding of cattle, without

just mentioning another practice common among our best farmers in

Bavaria, which, I think, deserves to be known. They chop the

green clover with which they feed their cattle, and mix with it a

considerable quantity of chopped straw. They pretend that this

rich succulent grass is of so clammy a nature, that unless it be

mixed with chopped straw, hay, or some other dry fodder, cattle

which are fed with it do not ruminate sufficiently. The usual

proportion of the clover to the straw, is as two to one.

[4]

A viertl is the twelfth part of a schafl, and the Bavarian schafl

is equal to 6 31/300 Winchester bushels.

[5]

The quantity of fuel here mentioned, though it certainly is

almost incredibly small, was nevertheless determined from the

results of actual experiments. A particular account of these

experiments will be given in my Essay on the Management of Heat

and the Economy of Fuel.

[6]

One Bavarian schafl (equal to 6 31/100 Winchester bushels) of

barley, weighing at a medium 250 Bavarian pounds, upon being

pearled, or rolled (as it is called in Germany), is reduced to

half a schafl, which weighs 171 Bavarian pounds. The 79lb. which

it loses in the operation is the perquisite of the miller, and is

all he receives for his trouble.

[7]

Since the First Edition of this Essay was published the experiment

with barley-meal has been tried, and the meal has been found to

answer quite as well as pearl barley, if not better, for making

these soups. Among others, Thomas Bernard, Esq. Treasurer of

the Founding Hospital, a gentleman of most respectable character,

and well known for his philanthropy and active zeal in relieving

the distresses of the Poor, has given it a very complete and fair

trial; and he found, what is very remarkable, though not difficult

to be accounted for--that the barley-meal, WITH ALL THE BRAN IN IT,

answered better, that is to say, made the soup richer, and thicker,

than when the fine flour of barley, without the bran, was used.

[8]

By some experiments lately made it has been found that the soup

will be much improved if a small fire is made under the boiler,

just sufficient to make its contents boil up once, when the

barley and water are put into it, and then closing up immediately

the ash-hole register, and the damper in the chimney,

and throwing a thick blanket, or a warm covering over the cover

of the boiler, the whole be kept hot till the next morning.

This heat so long continued, acts very powerfully on the barley,

and causes it to thicken the water in a very surprising manner.

Perhaps the oat-meal used for making water gruel might be

improved in its effects by the same means. The experiment is

certainly worth trying.

[9]

This invention of double bottoms might be used with great success

by distillers, to prevent their liquor, when it is thick, from

burning to the bottoms of their stills. But there is another

hint, which I have long wished to give distillers, from which,

I am persuaded, they might derive very essential advantages.--It is

to recommend to them to make up warm clothing of thick blanketing

for covering up their still-heads, and defending them from the

cold air of the atmosphere; and for covering in the same manner

all that part of the copper or boiler which rises above the

brick-work in which it is fixed. The great quantity of heat is

constantly given off to the cold air of the atmosphere in contact

with it by this naked copper, not only occasions a very great

loss of heat, and of fuel, but tends likewise very much to

EMBARRASS and to PROLONG the process of distillation; for all

the heat communicated by the naked still-head to the atmosphere

is taken from the spirituous vapour which rises from the liquor

in the still; and as this vapour cannot fail to be condensed into

spirits whenever and WHEREVER it loses ANY PART of its heat,--

as the spirits generated in the still-head in consequence of this

communication of heat to the atmosphere do not find their way

into the worm, but trickle down and mix again with the liquor in

the still,--the bad effects of leaving the still-head exposed

naked to the cold air is quite evident. The remedy for this evil

is as cheap and as effectual, as it is simple and obvious.

[10]

The Bavarian pound (equal to 1.238, or near one pound and a

quarter Avoirdupois,) is divided into 32 loths.

[11]

For each 100 lb. Bavarian weight, (equal to 123.84 lb.

Avoirdupois,) of rye-meal, which the baker receives from the

magazine, he is obliged to deliver sixty-four loaves of bread,

each loaf weighing 2 lb. 5 1/2 loths; equal to 2 lb. 10 oz.

Avoirdupois;--and as each loaf is divided into six portions,

this gives seven ounces Avoirdupois for each portion. Hence it

appears that 100 lb. of rye-meal give 149 lb. of bread; for

sixty-four loaves, at 2 lb. 5 1/2 loths each, weigh 149 lb.

--When this bread is reckoned at two creutzers a Bavarian pound,

(which is about what it costs at a medium,) one portion costs

just 10/16 of a creutzer, or 120/528 of a penny sterling, which

is something less than one farthing.

[12]

This allowance is evidently much too large; but I was willing to

show what the expence of feed the Poor would be at THE HIGHEST

CALCULATION. I have estimated the 7 ounces of rye-bread,

mentioned above, at what it ought to cost when rye is 7s. 6d. the

bushel, its present price in London.

[13]

Farther inquiries which have since been made, have proved that

these suspicions were not without foundation.

[14]

Since writing the above, I have had an opportunity of ascertaining,

in the most decisive and satisfactory manner, the facts relative

to the weight of Indian Corn of the growth of the northern states

of America. A friend of mine, an American gentleman, resident in

London, (George Erving, Esq. of Great George street, Hanover-square,)

who, in common with the rest of his countrymen, still retains a

liking for Indian Corn, and imports it regularly every year from

America, has just received a fresh supply of it, by one of the

last ships which has arrived from Boston in New England; and at

my desire he weighed a bushel of it, and found it to weigh 61 lb.:

It cost him at Boston three shillings and sixpence sterling the

bushel.

[15]

The price of Indian meal as it here estimated,--(2d. a pound,)

--is at least twice as much as it would cost in Great Britain in

common years, if care was taken to import it at the cheapest rate.

[16]

Those who dislike trouble, and feel themselves called upon by

duty and honor to take an active part in undertakings for the

public good, are extremely apt to endeavour to excuse,--to

themselves as well as to the world,--their inactivity and

supineness, by representing the undertaking in question as being

so very difficult as to make all hope of success quite chimerical

and ridiculous.

[17]

The Housekeeper of my friend and countryman, Sir William Pepperel,

Bart. of Upper Seymour Street, Portman Square.

[18]

Molasses imported from the French West India Islands into the

American States is commonly sold there from 12d. to 14d.

the gallon.

[19]

This gentleman, who is as remarkable for his good fortune at sea,

as he is respectable on account of his private character and

professional knowledge, has crossed the Atlantic Ocean the almost

incredible number of ONE HUNDRED AND TEN TIMES! and without

meeting with the smallest accident. He is now on the seas in his

way to North America; and this voyage, which is his HUNDRED AND

ELEVENTH, he intends should be his last. May he arrive

safe,--and may he long enjoy in peace and quite the well-earned

fruits of his laborious life! Who can reflect on the innumerable

storms he must have experienced, and perils he has escaped,

without feeling much interested in his preservation and

happiness?

[20]

This maccaroni would not probably have cost one quarter of that

sum at Naples.--Common maccaroni is frequently sold there as low

as fourteen grains, equal to five pence halfpenny sterling the

rottolo, weighing twenty-eight ounces and three quarters

Avoirdupois, which is three pence sterling the pound Avoirdupois.

An inferiour kind of maccaroni, such as is commonly sold at

Naples to the Poor, costs not more than two pence sterling the

pound Avoirdupois.

[21]

If maccaroni could be made in this country as cheap as it is made

in Naples, that is to say, so as to be afforded for three pence

sterling the pound Avoirdupois, for the best sort, (and I do not

see why it should not,) as half a pound of dry maccaroni weighs

when boiled very nearly two pounds, each pound of boiled

maccaroni would cost only three farthings, and the cheese

necessary for giving it a relish one farthing more, making

together one penny; which is certainly a very moderate price for

such good and wholesome Food.

CONTENTS of ESSAY IV.

of CHIMNEY FIRE-PLACES, with PROPOSALS for improving them to save

FUEL; to render dwelling-houses more COMFORTABLE and SALUBRIOUS,

and effectually to prevent CHIMNIES from SMOKING.

CHAPTER. I.

Fire-places for burning coals, or wood, in an open chimney,

are capable of great improvement.

Smoking chimnies may in all cases be completely cured.

The immoderate size of the throats of chimnies the principal

cause of all their imperfections.

Philosophical investigation of the subject.

Remedies proposed for all the defects that have been discovered

in chimnies and their open fire-places.

These remedies applicable to chimnies destined for burning

wood, or turf, as well as those constructed for burning coals.

CHAPTER. II.

Practical directions designed for the use of workmen, showing

how they are to proceed in making the alterations necessary to

improve chimney fire-places, and effectually to cure smoking

chimnies.

CHAPTER. III.

Of the cause of the ascent of smoke.

Illustration of the subject by familiar comparisons and

experiments.

Of chimnies which affect and cause each other to smoke.

Of chimnies which smoke from want of air.

Of the eddies of wind which sometimes blow down chimnies,

and cause them to smoke.

Explanation of the figures.

ESSAY IV.

The Author thinks it his duty to explain the reasons which have

induced him to change the order in which the publication of his

Essays has been announced to the Public.--Being suddenly called

upon to send to Edinburgh a person acquainted with the method of

altering Chimney Fire-places, which has lately been carried into

execution in a number of houses in London, in order to introduce

these improvements in Scotland, he did not think it prudent to

send any person on so important an errand without more ample

instruction than could well be given verbally; and being obliged

to write on the subject, he thought it best to investigate the

matter thoroughly, and to publish such particular directions

respecting the improvements in question as may be sufficient to

enable all those, who may be desirous of adopting them, to make,

or direct the necessary alterations in their Fire-places without

any further assistance.

The following Letter, which the Author received from Sir John

Sinclair, Baronet, Member of Parliament, and President of the

Board of Agriculture, will explain this matter more fully:

You will hear with pleasure that your mode of altering Chimnies,

so as to prevent their smoking, to save fuel, and to augment

heat, has answered not only with me, but with many of my friends

who have tried it; and that the Lord Provest and Magistrates of

Edinburgh have voted a sum of money to defray the expences of a

bricklayer, who is to be sent there for the purpose of

establishing the same plan in that city. I hope that you will

have the goodness to expedite your paper upon the management of

Heat, that the knowledge of so useful an art may be as rapidly

and as extensively diffused as possible.--With my best wishes for

your success in the various important pursuits in which you are

now engaged, believe me, with great truth and regard,

Your faithful and obedient servant

John Sinclair

Whitehall, London,

9th February 1796.

CHAPTER. I.

Fire-places for burning coals, or wood, in an open chimney,

are capable of great improvement.

Smoking chimnies may in all cases be completely cured.

The immoderate size of the throats of chimnies the principal

cause of all their imperfections.

Philosophical investigation of the subject.

Remedies proposed for all the defects that have been discovered

in chimnies and their open fire-places.

These remedies applicable to chimnies destined for burning

wood, or turf, as well as those constructed for burning coals.

The plague of a smoking Chimney is proverbial; but there are many

other very great defects in open Fire-places, as they are now

commonly constructed in this country, and indeed throughout

Europe, which, being less obvious, are seldom attended to;

and there are some of them very fatal in their consequences to

health; and, I am persuaded, cost the lives of thousands every

year in this island.

Those cold and chilling draughts of air on one side of the body,

while the other side is scorched by a Chimney Fire, which every

one who reads this must often have felt, cannot but be highly

detrimental to health; and in weak and delicate constitutions

must often produce the most fatal effects.--I have not a doubt in

my own mind that thousands die in this country every year of

consumptions occasioned solely by this cause.--By a cause which

might be so easily removed!--by a cause whose removal would tend

to promote comfort and convenience in so many ways.

Strongly impressed as my mind is with the importance of this

subject, it is not possible for me to remain silent.--The subject

is too nearly connected with many of the most essential

enjoyments of life not to be highly interesting to all those who

feel pleasure in promoting, or in contemplating the comfort and

happiness of mankind.--And without suffering myself to be

deterred, either by the fear of being thought to give the subject

a degree of importance to which it is not entitled, or by the

apprehension of being tiresome to my readers by the prolixity of

my descriptions,--I shall proceed to investigate the subject in

all its parts and details with the utmost care and attention.

--And first with regard to smoking Chimnies:

There are various causes by which Chimnies may be prevented from

carrying smoke; but there are none that may not easily be

discovered and completely removed.--This will doubtless be

considered as a bold assertion; but I trust I shall be able to

make it appear in a manner perfectly satisfactory to my readers

that I have not ventured to give this opinion but upon good and

sufficient grounds.

Those who will take the trouble to consider the nature and

properties of elastic fluids,--of air,--smoke,--and vapour,--

and to examine the laws of their motions, and the necessary

consequences of their being rarified by heat, will perceive that

it would be as much a miracle if smoke should not rise in a

Chimney, (all hindrances to its ascent being removed,) as that

water should refuse to run in a syphon, or to descend in a river.

The whole mystery, therefore, of curing smoking Chimnies is

comprised in this simple direction. --FIND OUT AND REMOVE THOSE

LOCAL HINDRANCES WHICH FORCIBLY PREVENT THE SMOKE FROM FOLLOWING

ITS NATURAL TENDENCY TO GO UP THE CHIMNEY; or rather, to speak

more accurately, which prevents its being forced up the Chimney

by the pressure of the heavier air of the room.

Although the causes, by which the ascent of smoke in a Chimney

MAY BE obstructed, are various, yet that cause which will most

commonly, and I may say almost universally be found to operate,

is one which it is always very easy to discover, and as easy to

remove,--the bad construction of the Chimney IN THE NEIGHBOURHOOD

OF THE FIRE-PLACE.

In the course all my experience and practice in curing smoking

Chimnies,--and I certainly have not had less than five hundred

under my hands, and among them many which were thought to be

quite incurable,--I have never been obliged, except in one

single instance, to have recourse to any other method of cure

than merely reducing the Fire-place and the throat of the

Chimney, or that part of it which lies immediately above the

Fire-place, to a proper form, and just dimensions.

That my principles for constructing Fire-places are equally

applicable to those which are designed for burning coal, as to

those in which wood is burnt, has lately been abundantly proved

by experiments made here in London; for of above an hundred and

fifty Fire-places which have been altered in this city, under my

direction, within these last two months, there is not one which

has not answered perfectly well[1].--And by several experiments

which have been made with great care, and with the assistance of

thermometers, it has been demonstrated, that the saving of fuel,

arising from these improvements of Fire-places, amounts in all

cases to more than HALF, and in many cases to more than TWO THIRDS

of the quantity formerly consumed.--Now as the alterations in

Fire-places which are necessary may be made at a very trifling

expence, as any kind of grate or stove may be made use of, and as

no iron work, but merely a few bricks and some mortar, or a few

small pieces of fire-stone, are required; the improvement in

question is very important, when considered merely with a view

to economy; but it should be remembered, that not only a great

saving is made of fuel by the alterations proposed, but that

rooms are made much more comfortable, and more salubrious;--

that they may be more equally warmed, and more easily kept at any

required temperature;--that all draughts of cold air from the

doors and windows towards the Fire-place, which are so fatal to

delicate constitutions, will be completely prevented;--that in

consequence of the air being equally warm all over the room, or

in all parts of it, it may be entirely changed with the greatest

facility, and the room completely ventilated, when this air is

become unfit for respiration, and this merely by throwing open

for a moment a door opening into some passage from whence fresh

air may be had, and the upper part of a window; or by opening the

upper part of on window and the lower part of another, and as the

operation of ventilating the room, even when it is done in the

most complete manner, will never require the door and window to

be open more than one minute; in this short time the walls of the

room will not be sensibly cooled, and the fresh air which comes

into the room will, in a very few minutes, be so completely

warmed by these walls that the temperature of the room, though

the air in it be perfectly changed, will be brought to be very

nearly the same as it was before the ventilation.

Those who are acquainted with the principles of pneumatics,

and know why the warm air in a room rushes out at an opening made

for it at the top of a window when colder air from without is

permitted to enter by the door, or by any other opening situated

lower than the first, will see, that it would be quite impossible

to ventilate a room in the complete and expeditious manner here

described, where the air in a room is partially warmed, or hardly

warmed at all, and where the walls of the room, remote from the

fire, are constantly cold; which must always be the case where,

in consequence of a strong current up the Chimney, streams of

cold air are continually coming in through all the crevices of

the doors and windows, and flowing into the Fire-place.

But although rooms, furnished with Fire-places constructed upon

the principles here recommended, may be easily and most

effectually ventilated, (and this is certainly a circumstance in

favour of the proposed improvements,) yet such total ventilations

will very seldom, if ever, be necessary.--As long as ANY FIRE is

kept up in the room, there is so considerable a current of air up

the Chimney, notwithstanding all the reduction that can be made

in the size of its throat, that the continual change of air in

the room which this current occasions will, generally, be found

to be quite sufficient for keeping the air in the room sweet and

wholesome; and indeed in rooms in which there is no open Fire-place,

and consequently no current of air from the room setting up the

Chimney, which is the case in Germany, and all the northern parts

of Europe, where rooms are heated by stoves, whose Fire-places

opening without are not supplied with the air necessary for the

combustion of the fuel from the room;--and although in most of

the rooms abroad, which are so heated, the windows and doors are

double, and both are closed in the most exact manner possible,

by slips of paper pasted over the crevices, or by slips of list or

furr; yet when these rooms are tolerably large, and when they are

not very much crowded by company, nor filled with a great many

burning lamps or candles, the air in them is seldom so much

injured as to become oppressive or unwholesome; and those who

inhabit them show by their ruddy countenances, as well as by

every other sign of perfect health, that they suffer no

inconvenience whatever from their closeness.--There is frequently,

it is true, an oppressiveness in the air of a room heated by a

German stove, of which those who are not much accustomed to

living in those rooms seldom fail to complain, and indeed with

much reason; but this oppressiveness does not arise from the air

of the room being injured by the respiration and perspiration of

those who inhabit it;--it arises from a very different cause;--

from a fault in the construction of German stoves in general,

but which may be easily and most completely remedied, as I shall

show more fully in another place. In the mean time, I would just

observe here with regard to these stoves, that as they are often

made of iron, and as this metal is a very good conductor of heat,

some part of the stove in contact with the air of the room

becomes so hot as to calcine or rather to ROAST the dust which

lights upon it; which never can fail to produce a very

disagreeable effect on the air of the room. And even when the

stove is constructed of pantiles or pottery-ware, if any part of

it in contact with the air of the room is suffered to become very

hot, which seldom fails to be the case in German stoves

constructed on the common principles, nearly the same effects

will be found to be produced on the air as when the stove is made

of iron, as I have very frequently had occasion to observe.

Though a room be closed in the most perfect manner possible, yet,

as the quantity of air injured and rendered unfit for further use

by the respiration of two or three persons in a few hours is very

small, compared to the immense volume of air which a room of a

moderate size contains; and as a large quantity of fresh air

always enters the room, and an equal quantity of the warm air of

the room is driven out of it every time the door is opened, there

is much less danger of the air of a room becoming unwholesome for

the want of ventilation than has been generally imagined;

particularly in cold weather, when all the different causes which

conspire to change the air of warmed rooms act with increased

power and effect.

Those who have any doubts respecting the very great change of air

or ventilation which takes place each time the door of a warm room

is opened in cold weather, need only set the door of such a room

wide open for a moment, and hold two lighted candles in the

door-way, one near the top of the door, and the other near the

bottom of it; the violence with which the flame of that above

will be driven outwards, and that below inwards, by the two

strong currents of air which, passing in opposite directions,

rush in and out of the room at the same time, will be convinced

that the change of air which actually takes place must be very

considerable indeed; and these currents will be stronger,

and consequently the change of air greater, in proportion as the

difference is greater between the temperature of the air within

the room and of that without. I have been more particular upon

this subject,--the ventilation of warmed rooms which are

constantly inhabited,--as I know that people in general in this

country have great apprehensions of the bad consequences to

health of living rooms in which there is not a continual influx

of cold air from without. I am as much an advocate for a FREE

CIRCULATION of air as any body, and always sleep in a bed without

curtains on that account; but I am much inclined to think, that

the currents of cold air which never fail to be produced in rooms

heated by Fire-places constructed upon the common principle,--

those partial heats on one side of the body, and the cold blasts

on the other, so often felt in houses in this country, are

infinitely more detrimental to health than the supposed closeness

of the air in a room warmed more equally, and by a smaller fire.

All these advantages, attending the introduction of the

improvements in Fire-places here recommended, are certainly

important, and I do not know that they are counterbalanced by any

one disadvantage whatsoever. The only complaints that I had ever

heard made against them was, that they made the rooms TOO warm;

but the remedy to this evil is so perfectly simple and obvious,

that I should be almost afraid to mention it, less it might be

considered as an insult to the understanding of the persons to

whom such information should be given; for nothing surely can be

conceived more perfectly ridiculous than the embarrassment of a

person on account of the too great heat of his room, when it is

in his power to diminish AT PLEASURE the fire by which it is

warmed; and yet, strange as it may appear, this has sometimes

happened!

Before I proceed to give directions for the construction of

Fire-places, it will be proper to examine more carefully the

Fire-places now in common use;--to point out their faults;--

and to establish the principles upon which Fire-places ought to

be constructed.

The great fault of all the open Fire-places, or Chimnies, for

burning wood or coals in an open fire, now in common use, is,

that they are much too large; or rather it is THE THROAT OF THE

CHIMNEY or the lower part of its open canal, in the neighbourhood

of the mantle, and immediately over the fire, which is too large.

This opening has hitherto been left larger than otherwise it

probably would have been made, in order to give a passage to the

Chimney-sweeper; but I shall show hereafter how a passage for the

Chimney-sweeper may be contrived without leaving the throat of

the Chimney of such enormous dimensions as to swallow up and

devour all the warm air of the room, instead of merely giving a

passage to the smoke and heated vapour which rise from the fire,

for which last purpose alone it ought to be destined.

Were it my intention to treat my subject in a formal scientific

manner, it would be doubtless be proper, and even necessary, to

begin by explaining in the fullest manner, and upon the

principles founded on the laws of nature, relative to the motions

of elastic fluids, as far as they have been discovered and

demonstrated, the causes of the ascent of smoke, and also to

explain and illustrate upon the same principles, and even to

measure, or estimate by calculations, the precise effects of all

those mechanical aids which may be proposed for assisting it in

its ascent, or rather for removing those obstacles which hinder

its motion upwards;--but as it is my wish rather to write an

useful practical treatise, than a learned dissertation, being

more desirous to contribute in diffusing useful knowledge, by

which the comforts and enjoyments of mankind may be increased,

than to acquire the reputation of a philosopher among learned

men, I shall endeavour to write in such a manner as to be easily

understood BY THOSE WHO ARE MOST LIKELY TO PROFIT BY THE

INFORMATION I HAVE TO COMMUNICATE, and consequently most likely

to assist in bringing into general use the improvements I

recommend. This being premised, I shall proceed, without any

further preface or introduction, to the investigation of the

subject I have undertaken to treat.

As the immoderate size of the throats of Chimnies is the great

fault of their construction, it is this fault which ought always

to be first attended to in every attempt which is made to improve

them; for however perfect the construction of a Fire-place may be

in other respects, if the opening left for the passage of the smoke

is larger than is necessary for that purpose, nothing can prevent

the warm air of the room from escaping through it; and whenever

this happens, there is not only an unnecessary loss of heat,

but the warm air which leaves the room to go up the Chimney being

replaced by cold air from without, the draughts of cold air,

so often mentioned, cannot fail to be produced in the room, to the

great annoyance of those who inhabit it. But although both these

evils may be effectually remedied by reducing the throat of the

Chimney to a proper size, yet in doing this several precautions

will be necessary. And first of all, the throat of the Chimney

should be in its proper place; that is to say, in that place in

which it ought to be, in order that the ascent of the smoke may

be most facilitated; for every means which can be employed for

facilitating the ascent of the smoke in the Chimney must naturally

tend to prevent the Chimney from smoking: now as the smoke and

hot vapour which rise from a fire naturally tend UPWARDS, the

proper place for the throat of the Chimney is evidently

perpendicularly OVER THE FIRE.

But there is another circumstance to be attended to in

determining the proper place for the throat of a Chimney,

and that is, to ascertain its distance from the fire, or HOW FAR

above the burning fuel it ought to be placed. In determining

this point, there are many things to be considered, and several

advantages and disadvantages to be weighed and balanced.

As the smoke and vapour which ascend from burning fuel rise in

consequence of their being rarefied by heat, and made lighter

than the air of the surrounding atmosphere; and as the degree of

their rarefaction, and consequently their tendency to rise, is in

proportion to the intensity of their heat; and further, as they

are hotter near the fire than at a greater distance from it,

it is clear that the nearer the throat of a Chimney is to the fire,

the stronger will be, what is commonly called, its DRAUGHT,

and the less danger there will be of its smoking. But on the

other hand, when the draught of a Chimney is very strong, and

particularly when this strong draught is occasioned by the throat

of the Chimney being very near the fire, it may so happen that

the draught of air into the fire may become so strong, as to

cause the fuel to be consumed too rapidly. There are likewise

several other inconveniences which would attend the placing of

the throat of a Chimney VERY NEAR the burning fuel.

In introducing the improvements proposed, in Chimnies already built,

there can be no question in regard to the height of the throat of

the Chimney, for its place will be determined by the height of

the mantle. It can hardly be made lower than the mantle; and it

ought always to be brought down as nearly upon the level with the

bottom of it as possible. If the Chimney is apt to smoke,

it will sometimes be necessary either to lower the mantle or to

diminish the height of the opening of the Fire-place, by throwing

over a flat arch, or putting in a straight piece of stone from

one side of it to the other, or, which will be still more simple

and easy in practice, building a wall of bricks, supported by a

flat bar of iron, immediately under the mantle.

Nothing is so effectual to prevent Chimnies from smoking as

diminishing the opening of the Fire-place in the manner here

described, and lowering and diminishing the throat of the Chimney;

and I have always found, except in the single instance already

mentioned, that a perfect cure may be effected by THESE MEANS

ALONE, even in the most desperate cases. It is true, that when

the construction of the Chimney is very bad indeed, or its

situation very unfavourable to the ascent of the smoke, and

especially when both these disadvantages exist at the same time,

it may sometimes be necessary to diminish the opening of the

Fire-place, and particularly to lower it, and also to lower the

throat of the Chimney, more than might be wished: but still I

think this can produce no inconveniences to be compared with that

greatest of all plagues, a smoking Chimney.

The position of the throat of a Chimney being determined, the

next points to be ascertained are its size and form, and the

manner in which it ought to be connected with the Fire-place

below, and with the open canal of the Chimney above.

But as these investigations are intimately connected with those

which relate to the form proper to be given to the Fire-place

itself, we must consider them all together.

That these inquiries may be pursued with due method, and that the

conclusions drawn from them may be clear and satisfactory,

it will be necessary to consider, first, what the objects are

which ought principally to be had in view in the construction of

a Fire-place; and secondly, to see how these objects can best be

attained.

Now the design of a Chimney Fire being simply to warm a room,

it is necessary, first of all, to contrive matters so that the

room shall be actually warmed; secondly, that it be warmed with

the smallest expence of fuel possible; and, thirdly, that in

warming it, the air of the room be preserved perfectly pure,

and fit for respiration, and free from smoke and all disagreeable

smells.

In order to take measures with certainty for warming a room by

means of an open Chimney Fire, it will be necessary to consider

HOW, or in WHAT MANNER, such a Fire communicates heat to a room.

This question may perhaps, at the first view of it, appear to be

superfluous and trifling, but a more careful examination of the

matter will show it to be highly deserving of the most attentive

investigation.

To determine in what manner a room is heated by an open Chimney

Fire, it will be necessary first of all to find out, UNDER WHAT

FORM the heat generated in the combustion of the fuel exists,

and then to see how it is communicated to those bodies which are

heated by it.

In regard to the first of these subjects of inquiry, it is quite

certain that the heat which is generated in the combustion of the

fuel exists under TWO perfectly distinct and very different forms.

One part of it is COMBINED with the smoke, vapour, and heated air

which rise from the burning fuel, and goes off with them into the

upper regions of the atmosphere; while the other part, which

appears to be UNCOMBINED, or, as some ingenious philosophers have

supposed, combined only with light, is sent off from the fire in

rays in all possible directions.

With respect to the second subject of inquiry; namely, how this

heat, existing under these two different forms, is communicated

to other bodies; it is highly probable that the combined heat can

only be communicated to other bodies by ACTUAL CONTACT with the

body with which it is combined; and with regard to the rays which

are sent off by burning fuel, it is certain that THEY communicate

or generate heat only WHEN and WHERE they are stopped or

absorbed. In passing through air, which is transparent, they

certainly do not communicate any heat to it; and it seems highly

probable that they do not communicate heat to solid bodies by

which they are reflected.

In these respects they seem to bear a great resemblance to the

solar rays. But in order not to distract the attention of my

reader, or carry him too far away from the subject more

immediately under consideration, I must not enter too deeply into

these inquiries respecting the nature and properties of what has

been called RADIANT HEAT. It is certainly a most curious subject

of philosophical investigation, but more time would be required

to do it justice than we now have to spare. We must therefore

content ourselves with such a partial examination of it as will

be sufficient for our present purpose.

A question which naturally presents itself here is.

What proportion does the radiant heat bear to the combined

heat?--Though that point has not yet been determined with any

considerable degree of precision, it is, however, quite certain,

that the quantity of heat which goes off combined with the smoke,

vapour, and heated air is much more considerable, perhaps three

of four times greater at least, than that which is sent off from

the fire in rays.--And yet, small as the quantity is of this

radiant heat, it is the only part of the heat generated in the

combustion of fuel burnt in an open Fire-place which is ever

employed, or which can ever be employed, in heating a room.

The whole of the combined heat escapes by the Chimney, and is

totally lost; and, indeed, no part of it could ever be brought

into a room from an open Fire-place, without bringing along with

it the smoke with which it is combined; which, of course, would

render it impossible for the room to be inhabited. There is,

however, one method by which combining heat, and even that which

arises from an open Fire-place, may be made to assist in warming

a room; and that is by making it pass through something analogous

to a German stove, placed in the Chimney above the fire.--But of

this contrivance I shall take occasion to treat more fully

hereafter; in the mean time I shall continue to investigate the

properties of open Chimney Fire-places, constructed upon the most

simple principles, such as are now in common use; and shall

endeavour to point out and explain all those improvements of

which THEY appear to me to be capable. When fuel is burnt in

Fire-places upon this simple construction, where the smoke

escapes immediately by the open canal of the Chimney, it is quite

evident that all the combined heat must of necessity be lost; and

as it is the radiant heat alone which can be employed in heating

a room, it becomes an object of much importance to determine how

the greatest quantity of it may be generated in the combustion of

the fuel, and how the greatest proportion possible of that

generated may be brought into the room.

Now the quantity of radiant heat generated in the combustion of a

given quantity of any kind of fuel depends very much upon the

management of the fire, or upon the manner in which the fuel is

consumed. When the fire burns bright, much radiant heat will be

sent off from it; but when it is SMOTHERED UP, very little will

be generated; and indeed very little combined heat, that can be

employed to any useful purpose: most of the heat produced will be

immediately EXPENDED in giving elasticity to a thick dense vapour

or smoke which will be seen rising from the fire; -- and the

combustion being very incomplete, a great part of the inflammable

matter of the fuel being merely rarefied and driven up the

Chimney without being inflamed, the fuel will be wasted to little

purpose. And hence it appears of how much importance it is,

whether it be considered with a view to economy, or to

cleanliness, comfort, and elegance, to pay due attention to the

management of a Chimney Fire.

Nothing can be more perfectly void of common sense, and wasteful

and slovenly at the same time, than the manner in which Chimney

Fires, and particularly where coals are burned, are commonly

managed by servants. They throw on a load of coals at once,

through which the flame is hours in making its way; and

frequently it is not without much trouble that the fire is

prevented from going quite out. During this time no heat is

communicated to the room; and what is still worse, the throat of

the Chimney being occupied merely by a heavy dense vapour,

not possessed of any considerable degree of heat, and consequently

not having much elasticity, the warm air of the room finds less

difficulty in forcing its way up the Chimney and escaping,

than when the fire burns bright;--and it happens not unfrequently,

especially in Chimneys and Fire-places ill constructed, that this

current of warm air from the room which presses into the Chimney,

crossing upon the current of heavy smoke which rises slowly from

the fire, obstructs it in its ascent, and beats it back into the

room; hence it is that Chimnies so often smoke when too large a

quantity of fresh coals is put upon the fire. So many coals

should never be put on the fire at once as to prevent the free

passage of the flame between them. In short, a fire should never

be smothered; and when proper attention is paid to the quantity

of coals put on, there will be very little use for the poker;

and this circumstance will contribute very much to cleanliness,

and to the preservation of furniture.

Those who have feeling enough to be made miserable by any thing

careless, slovenly, and wasteful which happens under their

eyes,--who know what comfort is, and consequence are worthy of

the enjoyments of a CLEAN HEARTH and a CHEERFUL FIRE, should

really either take the trouble themselves to manage their fires,

(which, indeed, would rather be an amusement to them than a

trouble,) or they should instruct their servants to manage them

better.

But to return to the subject more immediately under consideration.

As we have seen what is necessary to the production or generation

of radiant heat, it remains to determine how the greatest

proportion of that generated and sent off from the fire in all

directions may be made to enter the room, and assist in warming

it. How as the rays which are thrown off from burning fuel have

this property in common with light, that they generate heat only

WHEN and WHERE they are stopped or absorbed, and also in being

capable of being reflected WITHOUT GENERATING at the surfaces of

various bodies, the knowledge of these properties will enable us

to take measures, with the utmost certainty, for producing the

effect required,--that is to say, for bringing as much radiant

heat as possible into the room.

This must be done, first, by causing as many as possible of the

rays, as they are sent off from the fire in straight lines,

to come DIRECTLY into the room; which can only be effected by

bringing the fire as far forward as possible, and leaving the

opening of the Fire-place as wide and as high as can be done

without inconveniences; and secondly, by making the sides and

back of the Fire-place of such form, and constructing them of

such materials, as to cause the direct rays from the fire,

which strike against them, to be sent into the room BY REFLECTION

in the greatest abundance.

Now it will be found, upon examination, that the best form for

the vertical sides of a Fire-place, or the COVINGS, (as they are

called,) is that of an upright plane, making an angle with the

plane of the back of the Fire-place, of about 135 degrees.--

According to the present construction of Chimnies this angle is

90 degrees, or forms a right angle; but as in this case the two

sides or covings of the Fire-place (AC, BD, Fig. 1.) are

parallel to each other, it is evident that they are very ill

contrived for throwing into the room by reflection the rays from

the fire which fall on them.

To have a clear and perfect idea of the alterations I propose in

the forms of Fire-places, the reader need only observe, that,

whereas the backs of Fire-places, as they are now commonly

constructed, are as wide as the opening of the Fire-place in

front, and the sides of it are of course perpendicular to it, and

parallel to each other,--in the Fire-places I recommend, the back

(i k, Fig. 3) is only about one-third of the width of the opening

of the Fire-place in front (a,b), and consequently that the two

sides of covings of the Fire-place (a i and b k), instead of

being perpendicular to the back, are inclined to it at an angle

of about 135 degrees; and in consequence of this position,

instead of being parallel to each other, each of them presents an

oblique front towards the opening of the Chimney, by means of

which the rays which they reflect are thrown into the room.

A bare inspection of the annexed drawings (Fig. 1. and Fig. 3.)

will render this matter perfectly clear and intelligible.

In regard to the materials which it will be most advantageous to

employ in the construction of Fire-places, so much light has,

I flatter myself, already been thrown on the subject we are

investigating, and the principles adopted have been established

on such clear and obvious facts, that no great difficulty will

attend the determination of that point.--As the object in view is

to bring radiant heat into the room, it is clear that that

material is best for the construction of a Fire-place which

reflects the most, or which ABSORBS THE LEAST of it; for that

heat which is ABSORBED cannot be REFLECTED--Now as bodies which

absorb radiant heat are necessarily heated in consequence of that

absorption, to discover which of the various materials that can

be employed for constructing Fire-places are best adapted for

that purpose, we have only to find out by an experiment, very

easy to be made, what bodies acquire LEAST HEAT when exposed to

the direct rays of a clear fire;--for those which are least

heated, evidently absorb the least, and consequently reflect the

most radiant heat. And hence it appears that iron, and, in

general, metals of all kinds, which are well known to GROW VERY

HOT when exposed to the rays projected by burning fuel, are to be

reckoned among the VERY WORST materials that it is possible to

employ in the construction of Fire-places.

The best materials I have hitherto been able to discover are

fire-stone, and common bricks and mortar. Both these materials

are, fortunately, very cheap; and as to their comparative merits,

I hardly know to which of them the preference ought to be given.

When bricks are used they should be covered with a thin coating

of plaster, which, when it is become perfectly dry, should be

white-washed. The fire-stone should likewise be white washed,

when that is used; and every part of the Fire-place, which is not

exposed to being soiled and made black by the smoke, should be

kept as white and clean as possible. As WHITE reflects more

heat, as well as more light than any other colour, it ought

always to be preferred for the inside of a Chimney Fire-place,

and BLACK, which reflects neither light nor heat should be most

avoided.

I am well aware how much the opinion I have have ventured to

give, respecting the unfitness of iron and other metals to be

employed in the construction of open Fire-places, differs from

the opinion generally received upon that subject;--and I even

know that the very reason which, according to my ideas of the

matter, renders them totally unfit for the purpose, is commonly

assigned for making use of them, namely, that they soon grow very

hot. But I would beg leave to ask what advantage is derived from

heating them?

I have shown the disadvantage of it, namely, that the quantity of

radiant heat thrown into the room is diminished;--and it is easy

to show that almost the whole of that absorbed by the metal is

ultimately carried up the Chimney by the air, which, coming into

contact with this hot metal, is heated and rarefied by it,

and forcing its way upwards, goes off with the smoke; and as no

current of air ever sets from any part of the opening of a

Fire-place into the room, it is impossible to conceive how the

heat existing in the metal composing any part of the apparatus of

the Fire-place, and situated within its cavity, can come, or be

brought into the room.

This difficulty may be in part removed, by supposing, what

indeed seems to be true in a certain degree, that the heated

metal sends off rays, the heat it acquires from the fire, even

when it is not heated red hot; but still, as it never can be

admitted that the heat, absorbed by the metal and afterwards

thrown off by it in rays, is INCREASED by this operation, nothing

can be gained by it; and as much must necessary be lost in

consequence of the great quantity of heat communicated by the hot

metal to the air in contact with it, which, as has already been

shown, always makes its way up the Chimney, and flies off into

the atmosphere, the loss of heat attending the use of it is too

evident to require being farther insisted on.

There is, however, in Chimney Fire-places destined for burning

coals, one essential part, the grate, which cannot well be made

of any thing else but iron; but there is no necessity whatever

for that immense quantity of iron which surrounds grates as they

are now commonly constructed and fitted up, and which not only

renders them very expensive, but injures very essentially the

Fire-place. If it should be necessary to diminish the opening of

a large Chimney in order to prevent its smoking, it is much more

simple, economical, and better in all respects, to do this with

marble, fire-stone, or even with bricks and mortar, than to make

use of iron, which, as has already been shown, is the very worst

material that can possibly be employed for that purpose; and as

to registers, they not only are quite unnecessary, where the

throat of a Chimney is properly constructed, and of proper

dimensions, but in that case would do much harm. If they act at

all, it must be by opposing their flat surfaces to the current of

rising smoke in a manner which cannot fail to embarrass and

impede its motion. But we have shown that the passage of the

smoke through the throat of a Chimney ought to be facilitated as

much as possible, in order that it may be enabled to pass by a

small aperture.

because the great fault of all Fire-places constructed upon the

common principles being the enormous dimensions of the throat of

the Chimney, this fault has been in some measure corrected by

them; but I will venture to affirm, that there never was a

Fire-place so corrected that would not have been much more

improved, and with infinitely less expence, by the alterations

here recommended, and which will be more particularly explained

in the next Chapter.

CHAPTER. II.

Practical directions designed for the use of workmen, showing

how they are to proceed in making the alterations necessary to

improve chimney fire-places, and effectually to cure smoking

chimnies.

All Chimney Fire-places, without exception, whether they are

designed for burning wood or coals, and even those which do not

smoke, as well as those which do, may be greatly improved by

making the alterations in them here recommended; for it is by no

means MERELY to prevent Chimnies from smoking that these

improvements are recommended, but it is also to make them better

in all other respects as Fire-places; and when the alterations

proposed are properly executed, which may be very easily be done

with the assistance of the following plain and simple

directions, the Chimnies will never fail to answer, I will

venture to say, even beyond expectation. The room will be heated

much more equally and more pleasantly with LESS THAN HALF THE

FUEL used before, the fire will be more cheerful and more

agreeable; and the general appearance of the Fire-place more neat

and elegant, and the Chimney WILL NEVER SMOKE.

The advantages which are derived from mechanical inventions and

contrivances are, I know, frequently accompanied by disadvantages

which it is not always possible to avoid; but in the case in

question, I can say with truth, that I know of no disadvantage

whatever that attends the Fire-places constructed upon the

principles here recommended. --But to proceed in giving

directions for the construction of these Fire-places.

That what I have to offer on this subject may be the more easily

understood, it will be proper to begin by explaining the precise

meaning of all those technical words and expressions which I may

find it necessary or convenient to use.

By the THROAT of a Chimney, I mean the lower extremity of its

canal, where it unites with the upper part of its open Fire-place.

--This throat is commonly found about a foot above the level of

the lower part of the mantle, and it is sometimes contracted to a

smaller size than the rest of the canal of the Chimney,

and sometimes not.

Fig. 5. shows the section of a Chimney on the common

construction, in which d e is the throat.

Fig. 6. shows the section of the same Chimney altered and

improved, in which d i is the reduced throat.

The BREAST of a Chimney, is that part of it which is immediately

behind the mantle.--It is the wall which forms the entrance from

below into the throat of the Chimney in front, or towards the

room.--It is opposite to the upper extremity of the back of the

open Fire-place, and parallel to it; in short it may said to be

the back part of the mantle itself.--In the figures 5 and 6,

it is marked by the letter d. The WIDTH of the throat of Chimney

(d e fig. 5, and d i fig. 6,) is taken from the breast of the

Chimney to the back, and its LENGTH is taken at right angles to

its width, or in a line parallel to the mantle (a fig. 5. and 6.).

Before I proceed to give particular directions respecting the

exact forms and dimensions of the different parts of a Fire-place,

it may be useful to make such general an practical observations

upon the subject as can be clearly understood without the

assistance of drawings; for the more complete the knowledge of

any subject is which can be acquired without drawings, the more

easy will it be to understand the drawings when it becomes

necessary to have recourse to them.

The bringing forward of the Fire into the room, or rather

bringing it nearer to the front of the opening of the

Fire-place;--and the diminishing of the throat of the Chimney,

being two objects principally had in view in the alterations in

Fire-places here recommended, it is evident that both these may

be attained merely by bringing forward the back of the Chimney.

--The only question therefore is, how far it should be brought

forward?--The answer is short, and easy to be understood;--bring

it forward as far as possible, without diminishing too much the

passage which must be left for the smoke. Now as this passage,

which, in its narrowest part, I have called the THROAT OF THE

CHIMNEY, ought, for reasons which are fully explained in the

foregoing Chapter, to be immediately, or perpendicularly over the

Fire, it is evident that the back of the Chimney must always be

built perfectly upright.--To determine therefore the place for

the new back, or how far precisely it ought to be brought

forward, nothing more is necessary than to ascertain how wide

the throat of the Chimney ought to be left, or what space must be

left, between the top of the breast of the Chimney, where the

upright canal of the Chimney begins, and the new back of the

Fire-place carried up perpendicularly to that height.

In the course of my numerous experiments upon Chimnies, I have

taken much pains to determine the width proper to be given to

this passage, and I have found, that, when the back of the

Fire-place is of a proper width, the best width for the throat of

a Chimney, when the Chimney and the Fire-place are at the usual

form and size, is FOUR INCHES.--Three inches might sometimes

answer, especially where the Fire-place is very small, and the

Chimney good, and well situated: but as it is always of much

importance to prevent those accidental puffs of smoke which are

sometimes thrown into rooms by the carelessness of servants in

putting on suddenly too many coals at once upon the fire, and as

I found these accidents sometimes happened when the throats of

Chimneys were made very narrow, I found that, upon the whole, all

circumstances being well considered, and advantages and

disadvantages compared and balanced, FOUR INCHES is the best

width that can be given to the throat of a chimney; and this,

whether the Fire-place be destined to burn wood, coals, turf,

or any other fuel commonly used for heating rooms by an open fire.

In Fire-places destined for heating very large halls, and where

very great fires are kept up, the throat of the Chimney may,

if it should be thought necessary, be made four inches and an half,

or five inches wide;--but I have frequently made Fire-places for

halls which have answered perfectly well where the throats of

the Chimnies have not been wider than four inches.

It may perhaps appear extraordinary, upon the first view of the

matter, that Fire-places of such different sizes should all

require the throat of the Chimney to be of the same width; but

when it is considered that the CAPACITY of the throat of a

Chimney does not depend on its width alone, but on its width and

LENGTH taken together; and that in large Fire-places, the width

of the back, and consequently the length of the throat of the

Chimney, is greater than in those which are smaller, this

difficulty vanishes.

And this leads us to consider another important point respecting

open Fire-places, and that is, the width which it will, in each

case, be proper to give to the back.--In Fire-places as they are

now commonly constructed, the back is of equal width with the

opening of the Fire-place in front;--but this construction is

faulty on two accounts.--First, in a Fire-place, so constructed,

the sides of the Fire-place, or COVINGS, as they are called, are

parallel to each other, and consequently ill-contrived to throw

out into the room the heat they receive from the fire in the form

of rays;--and secondly, the large open corners which are formed

by making the back as wide as the opening of the Fire-place in

front occasion eddies of wind, which frequently disturb the fire,

and embarrass the smoke in its ascent in such a manner as often

to bring it into the room.--Both these defects may be entirely

remedied by diminishing the width of the back of the Fire-place.

--The width which, in most cases, it will be best to give it,

is ONE THIRD of the width of the opening of the Fire-place in

front.--But it is not absolutely necessary to conform rigorously

to this decision, nor will it always be possible.--It will

frequently happen that the back of a Chimney must be made wider

than, according to the rule here given, it ought to be.--This

may be, either to accommodate the Fire-place to a stove, which

being already on hand, must, to avoid the expense of purchasing a

new one, be employed; or for other reasons;--and any small

deviation from the general rule will be attended with no

considerable inconvenience.--It will always be best, however,

to conform to it as far as circumstances will allow.

Where a Chimney is designed for warming a room of a middling size,

and where the thickness of the wall of the Chimney in front,

measured from the front of the mantle to the breast of the

Chimney, is nine inches, I should set off four inches more for

the width of the throat of the Chimney, which, supposing the back

of the Chimney to be built upright, as it always ought to be,

will give thirteen inches for the depth of the Fire-place,

measured upon the hearth, from the opening of the Fire-place in

front, to the back.--In this case thirteen inches would be a good

size for the width of the back; and three times thirteen inches,

or thirty-nine inches, for the width of the opening of the

Fire-place in front; and the angle made by the back of the

Fire-place and the sides of it, or covings, would be just 135

degrees, which is the best position they can have for throwing

heat into the room.

But I will suppose that in altering such a Chimney it is found

necessary, in order to accommodate the Fire-place to a grate or

stove already on hand, to make the Fire-place sixteen inches

wide. -- In that case, I should merely increase the width of the

back, to the dimensions required, without altering the depth of

the Chimney, or increasing the width of the opening of the

Chimney in front. --The covings, it is true, would be somewhat

reduced in their width, by this alteration; and their position

with respect to the plane of the back of the Chimney would be a

little changed; but these alterations would produce no bad

effects of any considerable consequence, and would be much less

likely to injure the Fire-place, than an attempt to bring the

proportions of its parts nearer to the standard, by increasing

the depth of the Chimney, and the width of its opening in

front;--or than an attempt to preserve that particular obliquity

of the covings which is recommended as the best, (135 degrees,)

by increasing the width of the opening of the Fire-place, without

increasing its depth.

In order to illustrate this subject more fully, we will suppose

one case more.--We will suppose that in the Chimney which is to

be altered, the width of the Fire-place in front is either wider

or narrower than it ought to be, in order that the different

parts of the Fire-place, after it is altered, may be of the

proper dimensions. In this case, I should determine the depth of

the Fire-place, and the width of the back of it, without any

regard to the width of the opening of the Fire-place in front;

and when this is done, if the opening of Fire-place should be

only two or three inches too wide, that is to say, only two or

three inches wider than is necessary in order that the covings

may be brought into their proper position with respect to the

back, I should not alter the width of this opening, but should

accommodate the covings to this width, by increasing their

breadth, and increasing the angle they make with the back of the

Fire-place; but if the opening of the Fire-place should be more

than three inches too wide; --I should reduce it to the proper

width by slips of stone, or by bricks and mortar.

When the width of the opening of the Fire-place, in front, is

very great, compared with the depth of the Fire-place, and with

the width of the back, the covings in that case being very wide,

and consequently very oblique, and the Fire-place very shallow,

any sudden motion of the air in front of the Fire-place, (that

motion, for instance, which would be occasioned by the clothes

of a woman passing hastily before the fire, and very near it,)

would be apt to cause eddies in the air, WITHIN THE OPENING OF

THE FIRE-PLACE, by which puffs of smoke might easily be brought

into the room. Should the opening of the Chimney be too narrow,

which however will very seldom be found to be the case, it will,

in general, be advisable to let it remain as it is, and to

accommodate the covings to it, rather to attempt to increase its

width, which would be attended with a good deal of trouble, and

probably a considerable expence.

From all that has been said it is evident, that the points of the

greatest importance, and which ought most particularly to be

attended to, in altering Fire-places upon the principles here

recommended, are, the bringing forward the back to its proper

place, and making it of a proper width.--But it is time that I

should mention another matter upon which it is probable that my

reader is already impatient to receive information.--Provision

must be made for the passage of the Chimney-sweeper up the

Chimney.--This may easily be done in the following manner:--

In building up the new back of the Fire-place; when this wall,

(which need never be more than the width of a single brick in

thickness,) is brought up so high that there remains no more than

about ten or eleven inches between what is then the top of it,

and the inside of the mantle, or lower extremity of the breast of

the Chimney, an opening, or door-way, eleven or twelve inches

wide, must be begun in the middle of the back, and continued

quite to the top of it, which, according to the height to which

it will commonly be necessary to carry up the back, will make the

opening about twelve or fourteen inches high; which will be quite

sufficient to allow the Chimney-sweeper to pass. When the

Fire-place is finished, this door-way is to be closed by a few

bricks, by a tile, or a fit piece of stone, placed in it, dry,

or without mortar, and confined in its place by means of a rabbet

made for that purpose in the brick-work.--As often as the Chimney

is swept, the Chimney-sweeper takes down this temporary wall,

which is very easily done, and when he has finished his work, he

puts it again into its place.--The annexed drawing (No. 6.) will

give a clear idea of this contrivance; and the experience I have

had of it has proved that it answers perfectly well the purpose

for which it is designed.

I observed above, that the new back, which it will always be

found necessary to build in order to bring the fire sufficiently

forward, in altering a Chimney constructed on the common

principles, need never be thicker than the width of a common

brick.--I may say the same of the thickness necessary to be given

to the new sides, or covings, of the Chimney; or if the new back

and covings are constructed of stone, one inch and three

quarters, or two inches in thickness will be sufficient.--Care

should be taken in building up these new walls to unite the back

to the covings in a solid manner.

Whether the new back and covings are constructed of stone,

or built of bricks, the space between them, and the old back and

covings of the Chimney ought to be filled up, to give greater

solidity to the structure.--This may be done with loose rubbish,

or pieces of broken bricks, or stones provided the work be

strengthened by a few layers or courses of bricks laid in mortar;

but it will be indispensably necessary to finish the work, where

these new walls end, that is to say, at the top of the throat of

the Chimney, where it ends abruptly in the open canal of the

Chimney by a horizontal course of bricks well secured with mortar.

--This course of bricks will be upon a level with the top of the

door-way left for the Chimney-sweeper.

From these descriptions it is clear that where the throat of the

Chimney has an end, that is to say, where it enters into the

lower part of the open canal of the Chimney, THERE the three

walls which form the two covings and the back of the Fire-place

all end abruptly.--It is of much importance that they should end

in this manner; for were they to be sloped outward and raised in

such a manner as to swell out the upper extremity of the throat

of the Chimney in the form of a trumpet, and increase it by

degrees to the size of the canal of the Chimney, this manner of

uniting the lower extremity of the canal of the Chimney with the

throat would tend to assist the winds which may attempt to blow

down the Chimney, in forcing their way through the throat, and

throwing the smoke backward into the room; but when the throat of

the Chimney ends abruptly, and the ends of the new walls form a

flat horizontal surface, it will be much more difficult for any

wind from above, to find, and force its way through the narrow

passage of the throat of the Chimney.

As the two walls which form the new covings of the Chimney are

not parallel to each other; but inclined, presenting an oblique

surface towards the front of the Chimney, and as they are built

perfectly upright and quite flat, from the hearth to the top of

the throat, where they end, it is evident that an horizontal

section of the throat will not be an oblong square; but its

deviation from that form is a matter of no consequence; and no

attempts should ever be made, by twisting the covings above,

where they approach the breast of the Chimney, to bring it to

that form.--All twists, bends, prominences, excavations,

and other irregularities of form, in the covings of a Chimney,

never fail to produce eddies in the current of air which is

continually passing into, and through an open Fire-place in which

a fire is burning;--and all such eddies disturb, either the fire,

or the ascending currents of smoke, or both; and not unfrequently

cause the smoke to be thrown back into the room.--Hence it appears,

that the covings of Chimneys should never be made circular, or in

the form of any other curve; but always quite flat.

For the same reason, that is to say, to prevent eddies,

the breast of the Chimney, which forms that side of the throat

that is in front, or nearest to the room, should be nearly

cleaned off, and its surface made quite regular and smooth.

This may easily be done by covering it with a coat of plaster,

which may be made thicker or thinner in different parts as may be

necessary in order to bring the breast of the Chimney to be of

the proper form.

With regard to the form of the breast of a Chimney, this is a

matter of very great importance, and which ought always to be

particularly attended to.--The worst form it can have is that of

a vertical plane, or upright flat;--and next to this the worst

form is an inclined plane.--Both these forms cause the current

of warm air from the room, which will, in spite of every

precaution, sometimes find its way into the Chimney, to cross

upon the current of smoke, which rises from the fire, in a manner

most likely to embarrass it in its ascent, and drive it back.

--The inclined plane which is formed by a flat register placed in

the throat of a Chimney produces the same effects; and this is

one reason, among many others, which have induced me to

disapprove of register stoves.

The current of air, which, passing under the mantle, gets into

the Chimney, should be made GRADUALLY TO BEND ITS COURSE UPWARDS,

by which means it will be QUIETLY with the ascending current of

smoke, and will be less likely to check it, or force it back into

the room.--Now this may be effected with the greatest ease and

certainty, merely by ROUNDING OFF the breast of the Chimney or

back part of the mantle, instead of leaving it flat, or full of

holes and corners; and this of course ought always to be done.

I have hitherto given no precise directions in regard to the

height to which the new back and covings ought to be carried:--

This will depend not only on the height of the mantle, but also,

and more especially, on the height of the breast of the Chimney,

or of that part of the Chimney where the breast ends and the

upright canal begins.--The back and covings must rise a few

inches, five or six for instance, higher than this part,

otherwise the throat of the Chimney will not be properly

formed:--but I know of no advantages that would be gained by

carrying them up still higher.

I mentioned above, that the space between the walls which form

the new back and covings, and the old back and sides of the

Fire-place, should be filled up:--but this must not be understood

to apply to the space between the wall of dry bricks, or the tile

which closes the passage for the Chimney-sweeper, and the old

back of the Chimney; for that space must be left void, otherwise,

though this tile (which at most will not be more than two inches

in thickness,) were taken away, there would not be any room

sufficient for him to pass.

In forming this door-way, the best method of proceeding is to

place the tile or flat piece of stone destined for closing it, in

its proper place; and to build round it, or rather by the sides

of it; taking care not to bring any mortar near it, in order that

it may be easily removed when the door-way is finished.--With

regard to the rabbet which should be made in the door-way to

receive it and fix it more firmly in its place, this may either

be formed at the same time when the door-way is built, or it may

be made after it is finished, by attaching to its bottom and

sides, with strong mortar, pieces of thin roof tiles. Such as

are about half an inch in thickness will be best for this use;

if they are thicker, they will diminish too much the opening of

the door-way, and will likewise be more liable to be torn away by

the Chimney-sweeper in passing up and down the Chimney.

It will hardly be necessary for me to add, that the tile, or flat

stone, or wall of dry bricks, which is used for closing up the

door-way, must be of sufficient height to reach quite up to a

level with the top of the walls which form the new back and

covings of the Chimnies.

I ought, perhaps, to apologize for having been so very particular

in these description and explanations, but it must be remembered

that this chapter is written principally for the information of

those who, having had few opportunities of employing their

attention in abstruse philosophical researches, are not

sufficiently practised in these intricate investigations, to

seize, with facility, new ideas;--and consequently, that I have

frequently been obliged TO LABOUR to make myself understood.

I have only to express my wishes that my reader may not be more

FATIGUED with this labour than I have been;--for we shall them

most certainly be satisfied with each other.--But to return once

more to the charge.

There is one important circumstance respecting Chimney Fire-places,

destined for burning coals, which still remains to be farther

examined;--and that is the Grate.

Although there are few grates that may not be used in Chimneys

constructed or altered upon the principles here recommended,

yet they are not, by any means, all equally well adapted for that

purpose.--Those whose construction is the most simple, and which

of course are the cheapest, are beyond comparison the best,

ON ALL ACCOUNTS.--Nothing being wanted in these Chimnies but merely

a grate for containing the coals, and in which they will burn

with a clear fire;--and all additional apparatus being, not only

useless, but very pernicious, all complicated and expensive

grates should be laid aside, and such as more simple substituted

in the room of them.--And in the choice of a grate, as in every

thing else, BEAUTY and ELEGANCE may easily be united with the

MOST PERFECT SIMPLICITY.--Indeed they are incompatible with every

thing else.

In placing the grate, the thing principally to be attended to is,

to make the back of it coincide with the back of the Fire-place;--

but as many of the grates now in common use will be found to be

too large, when the Fire-places are altered and improved, it

will be necessary to diminish their capacities by filling them up

at the back and the sides with pieces of fire-stone. When this

is done, it is the front of the flat piece of fire-stone which is

made to form a new back to the grate, which must be made to

coincide with, and make part of the back, of the Fire-place.--

But in diminishing the capacities of grates with pieces of

fire-stone, care must be taken not to make them TOO NARROW.

The proper width for grates destined for rooms of a middling size

will be from six to eight inches, and their length may be

diminished more or less, according as the room is heated with

more or less difficulty, or as the weather is more or less severe.

--But where the width of a grate is not more than five inches,

it will be very difficult to prevent the fire from going out.

It goes out for the same reason that a live coal from the grate

that falls upon the hearth soon ceases to be red hot;--it is

cooled by the surrounding cold air of the atmosphere.--

The knowledge of the cause which produces this effect is important,

as it indicates the means which may be used for preventing it.

--But of this subject I shall treat more fully hereafter.

It frequently happens that the iron backs of grates are not

vertical, or upright, but inclined backwards.--When these grates

are so much too wide as to render it necessary to fill them up

behind with fire-stone, the inclination of the back will be of

little consequence; for by making the piece of stone with which

the width of the grate is to be diminished in the form of a

wedge, or thicker above than below, the front of this stone,

which in effect will become the back of the grate, may be made

perfectly vertical; and the iron back of the grate being hid in

the solid work of the back of the Fire-place, will produce no

effect whatever; but if the grate be already so narrow as not to

admit of any diminution of its width, in that case it will be

best to take away the iron back of the grate entirely, and fixing

the grate firmly in the brick-work, cause the back of the

Fire-place to serve as a back to the grate.--This I have very

frequently done, and have always found it to answer perfectly

well.

Where it is necessary that the fire in a grate should be very

small, it will be best, in reducing the grate with fire-stone,

to bring its cavity, destined for containing the fuel, to the form

of one half of a hollow hemisphere; the two semicircular openings

being one above, to receive the coals, and the other in front,

or towards the bars of the grate; for when the coals are burnt in

such a confined space, and surrounded on all sides, except in the

front and above, by fire-stone, (a substance peculiarly well

adapted for confining heat,) the heat of the fire will be

concentrated, and the cold air of the atmosphere being kept at a

distance, a much smaller quantity of coals will burn, than could

possibly be made to burn in a grate where they would be more

exposed to be cooled by the surrounding air, or to have their

heat carried off by being in contact with iron, or with any other

substance through which heat passes with greater facility than

through fire-stone.

Being persuaded that if the improvements in Chimney Fire-places

here recommended should be generally adopted, (which I cannot

help flattering myself will be the case,) that it will become

necessary to reduce, very considerably, the sizes of grates,

I was desirous of showing how this may, with the greatest safety

and facility, be done.

Where grates, which are designed for rooms of a middling size,

are longer than 14 or 15 inches, it will always be best, not

merely to diminish their lengths, by filling them up at their two

ends with fire-stone, but, forming the back of the Chimney of a

proper width, without paying any regard to the length of the

grate, to carry the covings through the two ends of the grate in

such a manner as to conceal them, or at least to conceal the back

corners of them in the walls of the covings.

I cannot help flattering myself that the directions here given in

regard to the alterations which it may be necessary to make in

Fire-places, in order to introduce the improvements proposed,

will be found to be so perfectly plain and intelligible that no

one who reads them will be at any loss respecting the manner in

which the work is to be performed; -- but as order and arrangement

tend much to facilitate all mechanical operations, I shall here

give a few short directions respecting the manner of LAYING OUT

THE WORK, which may be found useful, and particularly to

gentlemen who may undertake to be their own architects, in

ordering and directing the alterations to be made for the

improvement of their Fire-places.

Directions for laying out the Work.

If there be a grate in the Chimney which is to be altered,

it will always be best to take it away; and when this is done,

the rubbish must be removed, and the hearth swept perfectly clean.

Suppose the annexed figure No. 1. to represent the ground plan of

such a Fire-place; A B being the opening of it in front, A C and

B D the two sides or covings, and C D the back.

Figure 2. shows the elevation of this Fire-place.

First draw a strait line, with chalk, or with a lead pencil,

upon the hearth, from one jamb to the other,--even with the front

of the jambs. The dotted line A B, figure 3, may represent this

line.

From the middle C of this line, (A B) another line c d, is to be

drawn perpendicular to it, across the hearth, to the middle d, of

the back of the Chimney.

A person must now stand upright in the Chimney, with his back to

the back of the Chimney, and hold a plumb-line to the middle of

the upper part of the breast of the Chimney (d, fig. 5,) or

where the canal of the Chimney begins to rise perpendicularly;--

taking care to place the line above in such a manner that the

plumb may fall on the line c d, draw on the hearth from the

middle of the opening of the Chimney in front to the middle of

the back, and an assistant must mark the precise place e, on that

line where the plumb falls.

This being done, and the person in the Chimney having quitted his

station, four inches are to be set off the line c d, from e,

towards d; and the point f, where these four inches end,

(which must be marked with chalk, or with a pencil,) will show

how far the new back is to be brought forward.

Through f, draw the line g h, parallel to the line A B, and this

line g h will show the direction of the new back, or the ground

line upon which it is to be built.

The line c f will show the depth of the new Fire-place; and if it

should happen that c f is equal to about ONE-THIRD of the line A B;

and if the grate can be accommodated to the Fire-place instead

of its being necessary to accommodate the Fire-place to the

grate, in that case, half the length of the line c f, is to be

set off from f on the line g f h, on one side to k, and on the

other to i, and the line i k will show the ground line of the

fore part of the back of the Chimney.

In all cases where the width of the opening of the Fire-place in

front (A B) happens to be not greater, or not more than two or

three inches greater than THREE TIMES the width of the new back

of the Chimney (i k), this opening may be left, and lines drawn

from i to A, and from k to B, will show the width and position of

the front of the new covings;--but when the opening of the

Fire-place in front is still wider, it must be reduced; which is

to be done in the following manner:

From c, the middle of the line A B, c a and c b, must be set off

equal to the width of the back (i k), added to half its width

(f i), and lines drawn from i to a, and from k to b, will show the

ground plan of the fronts of the new covings.

When this is done, nothing more will be necessary than to build

up the back and covings; and if the Fire-place is designed for

burning coals, to fix the grate in its proper place, according to

the directions already given.--When the width of the Fire-place

is reduced, the edges of the covings a A and b B are to make a

finish with the front of the jambs.--And in general it will be

best, not only for the sake of the appearance of the Chimney,

but for other reasons also, to lower the height of the opening of

the Fire-place, whenever its width in front is diminished.

Fig. 4. shows a front view of the Chimney after it has been

altered according to the directions here given.--By comparing it

with fig. 2. (which shows a front view of the same Chimney before

it was altered), the manner in which the opening of the

Fire-place in front is diminished may be seen.--In fig. 4. the

under part of the door-way by which the Chimney-sweeper gets up

the Chimney is represented by white dotted lines. The door-way

is represented closed.

I shall finish this chapter with some general observations

relative to the subject under consideration; with directions how

to proceed where such local circumstances exist as render

modifications of the general plan indispensably necessary.

Whether a Chimney be designed for burning wood upon the hearth,

or wood, or coals in a grate, the form of the Fire-place is in my

opinion, most perfect when THE WIDTH OF THE BACK is equal to the

DEPTH OF THE FIRE-PLACE, and the opening of the Fire-place in

front equal to THREE TIMES the width of the back, or, which is

the same thing, to THREE TIMES THE DEPTH OF THE FIRE-PLACE.

But if the Chimney be designed for burning wood upon the hearth,

upon hand irons, or dogs, as they are called, it will sometimes

be necessary to accommodate the width of the back to the length

of the wood; and when this is the case, the covings must be

accommodated to the width of the back, and the opening of the

Chimney in front.

When the wall of the Chimney in front, measured from the upper

part of the breast of the Chimney to the front of the mantle, is

very thin, it may happen, and especially in Chimnies designed for

burning wood upon the hearth, or upon dogs, that the depth of the

Chimney, determined according to the directions here given, may

be too small.

Thus, for example, supposing the wall of the Chimney in front,

from the upper part of the breast of the Chimney to the front of

the mantle, to be only four inches, (which is sometimes the case,

particularly in rooms situated near the top of a house,) in this

case, if we take four inches for the width of the throat, this

will give eight inches only for the depth of the Fire-place,

which would be too little, even were coals to be burnt instead of

wood.--In this case I should increase the depth of the Fire-place

at the hearth to 12 or 13 inches, and should build the back

perpendicular to the height of the top of the burning fuel,

(whether it be wood burnt upon the hearth, or coals in a grate,)

and then, sloping the back by a gentle inclination forward, bring

it to its proper place, that is to say, PERPENDICULARLY UNDER THE

BACK OF THE THROAT OF THE CHIMNEY. This slope, (which will bring

the back forward four or five inches, or just as much as the

depth of the Fire-place is encreased,) though it ought not to be

too abrupt, yet it ought to be quite finished at the height of

eight or ten inches above the fire, otherwise it may perhaps

cause the Chimney to smoke; but when it is very near the fire,

the heat of the fire will enable the current of rising smoke to

overcome the obstacle which this slope will oppose to its ascent,

which it could not do so easily were the slope situated at a

greater distance from the burning fuel[2].

Fig. 7, 8, and 9, show a plan, elevation, and section of a

Fire-place constructed or altered upon this principal.--The wall

of the Chimney in front at a, fig. 9, being only four inches

thick, four inches more added to it for the width of the throat

would have left the depth of the Fire-place measured upon the

hearth b c only eight inches, which would have been too

little;--a niche c and e, was therefore made in the new back of

the Fire-place for receiving the grate, which niche was six

inches deep in the center of it, below 13 inches wide, (or equal

in width to the grate,) and 23 inches high; finishing above with

a semicirular arch, which, in its highest part, rose seven inches

above the upper part of the grate.--The door-way for the

Chimney-sweeper, which begins just above the top of the niche,

may be seen distinctly in both the figures 8 and 9.--The space

marked g, fig. 9, behind this door-way, may either be filled with

loose bricks, or may be left void.--The manner in which the piece

of stone f, fig. 9, which is put under the mantle of the Chimney

to reduce the height of the opening of the Fire-place, is rounded

off on the inside in order to give a fair run to the column of

smoke in its ascent through the throat of the Chimney, is clearly

expressed in this figure.

The plan fig. 7, and elevation fig. 8, show how much the width of

the opening of the Fire-place in front is diminished, and how the

covings in the new Fire-place are formed.

A perfect idea of the form and dimension of the Fire-place in its

original state, as also after its alteration, may be had by

careful inspection of these figures.

I have added the drawing fig. 10, merely to show how a fault,

which I have found workmen in general whom I have employed in

altering Fire-places are very apt to commit, is to be avoided.

--In Chimneys like that represented in this figure, where the

jambs A and B project far into the room, and where the front edge

of the marble slab, o which forms the coving, does not come so

far forward as the front of the jambs, the workmen in

constructing the new covings are very apt to place them,--not in

the line c A, which they ought to do,--but in the line c o, which

is a great fault.--The covings of a Chimney should never range

BEHIND the front of the jambs, however those jambs may project

into the room;--but it is not absolutely necessary that the

covings should MAKE A FINISH with the internal front corners of

the jambs, or that they should be continues from the back c,

quite to the front of the jambs at A.--They may finish in front

at a and b, and small corners A, o, a, may be left for placing

the shovels, tongs, etc.

Were the new coving to range with the front edge of the old

coving o, the obliquity of the new coving would commonly be too

great;--or the angle d c o would exceed 135 degrees, WHICH IT

NEVER SHOULD DO,--or at least never by more than a very few

degrees.

No inconvenience of any importance will arise from making the

obliquity of the covings LESS than what is here recommended;

but many cannot fail to be produced by making it much greater;--

and as I know from experience that workmen are very apt to do this,

I have thought it necessary to warn them particularly against it.

Fig. 11. shows how the width and obliquity of the covings of a

Chimney are to be accommodated to the width of the back, and to

the opening in front and depth of the Fire-place, where the width

of the opening of the Fire-place is less than three times the

width of the new back. As all those who may be employed in

altering Chimneys may not, perhaps, known how to set off an angle

of any certain numbers of degrees,--or may not have at hand the

instruments necessary for doing it,--I shall here show how an

instrument may be made which will be found to be very useful in

laying out the work for the bricklayers.

Upon a board about 18 inches wide and four feet long, or upon the

floor or a table, draw three equal squares A, B, C, fig. 12. of

about 12 or 14 inches each side, placed in a strait line, and

touching each other.--From the back corner c of the center square

B, draw a diagonal line across the square A, to its outward front

corner f, and the adjoining angle formed by the lines d c and c f

will be equal to 135 degrees,--the angle which the plane of the

back of a Chimney Fire-place ought to make with the plane of its

covings.--And a bevel m, n, being made to this angle with thin

slips of hard wood, this little instrument will be found to be

very useful in marking out on the hearth, with chalk, the plans

of the walls which are to form the covings of Fire-places.

As Chimneys which are apt to smoke will require the covings to be

placed less obliquely in respect to the back than others which

have not that defect, it would be convenient to be provided with

several bevels;--three or four, for instance, forming different

angles.--That already described, which may be called No. 1. will

measure the obliquity of the covings when the Fire-place can be

made of the most perfect form:--another No. 2. may be made to a

smaller angle, d c e,--and another No. 3. for Chimnies which are

very apt to smoke at the still smaller angle d c i.--Or a bevel

may be so contrived, by means of a joint, and an arch, properly

graduated, as to serve for all the different degrees of obliquity

which it may ever be necessary to give to the covings of

Fire-places.

Another point of much importance, and particularly in Chimneys

which are apt to smoke, is to form the throat of the Chimney

properly, by carrying up the back and covings to a proper

height. This, workmen are apt to neglect to do, probably on

account of the difficulty they find in working where the opening

of the canal of the Chimney is so much reduced.--But it is

absolutely necessary that these walls should be carried up five

or six inches at least above the upper part of the breast of the

Chimney, or to that point where the wall which forms the front of

the throat begins to rise perpendicularly. --If the workman has

intelligence enough to avail himself of the opening which is

formed in the back of the Fire-place to give a passage to the

Chimney-sweeper, he will find little difficulty in finishing his

work in a proper manner.

In placing the plumb-line against the breast of the Chimney, in

order to ascertain how far the new back is to be brought

forward, great care must be taken to place it at the very top of

the breast, where the canal of the Chimney BEGINS TO RISE

PERPENDICULARLY; otherwise, when the plumb-line is placed too

low, or against the slope of the breast, when the new back comes

to be raised to its proper height, the throat of the Chimney will

found to be too narrow.

Sometimes, and indeed very often the top of the breast of a

Chimney lies very high, or far above the fire (see the figures 13

and 14, where d shows the top of the breast of the Chimney);

when this is the case it must be brought lower, otherwise the

Chimney will be very apt to smoke.--So much has been said in the

First Chapter of this Essay of the advantages to be derived from

bringing the throat of a Chimney near to the burning fuel, that I

do not think it necessary to enlarge on them in this place,--

taking it for granted that the utility and necessity of that

arrangement have already been made sufficiently evident;--

but a few directions for workmen, to show them how the breast

(and consequently the throat) of a Chimney can most readily be

lowered, may not be superfluous.

Where the too great height of the breast of a Chimney is owing to

the great height of the mantle, (see fig. 13,) or, which is the

same thing, of the opening of the Fire-place in front, which will

commonly be found to be the case; the only remedy for the evil

will be to bring down the mantle lower;--or rather, to make the

opening of the Fire-place in front lower, by throwing across the

top of this opening, from one jamb to the other, and immediately

under the mantle, a very flat arch;--a wall of bricks and mortar,

supported on straight bars of iron;--or a piece of stone

(h, fig. 13).--When this is done, the slope of the old throat of

the Chimney, or of the back side of the mantle, is to be filled

up with plaster, so as to form one continued flat, vertical,

or upright plane surface with the lower part of the wall of the

canal of the Chimney, and a new breast is to be formed lower

down, care being taken to round it off properly, and make it

finish at the lower surface of the new wall built under the

mantle;--which wall forms in fact a new mantle.

The annexed drawing fig. 13, which represents the section of a

Chimney in which the breast has been lowered according to the

method here described, will show these various alterations in a

clear and satisfactory manner. In this figure, as well as in

most of the others in this Essay, the old walls are distinguished

from the new ones by the manner in which they are shaded;--

the old walls being shaded by diagonal lines, and the new ones by

vertical lines. The additions, which are formed of plaster,

are shaded by dots instead of lines.

Where the too great height of the breast of a Chimney is

occasioned, not by the height of the mantle, but by the too great

width of the breast, in that case, (which however will seldom be

found to occur,) this defect may be remedied by covering the

lower part of the breast with a thick coating of plaster,

supported, if necessary, by nails or studs, driven into the wall

which forms the breast, and properly rounded off at the lower

part of the mantle.--See fig. 14.

CHAPTER. III.

Of the cause of the ascent of smoke.

Illustration of the subject by familiar comparisons and

experiments.

Of chimnies which affect and cause each other to smoke.

Of chimnies which smoke from want of air.

Of the eddies of wind which sometimes blow down chimnies,

and cause them to smoke.

Explanation of the figures.

Though it was my wish to avoid all abstruse philosophical

investigations in this Essay, yet I feel that it is necessary to

say a few words upon a subject generally considered as difficult

to be explained, which is too intimately connected with the

matter under consideration to be passed over in silence.--

A knowledge of the cause of the ascent of Smoke being indispensably

necessary to those who engage in the improvement of Fire-places,

or who are desirous of forming just ideas relative to the

operations of fire, and the management of heat, I shall devote a

few pages to the investigation of that curious and interesting

subject.--And as many of those who may derive advantage from

these inquiries are not much accustomed to philosophical

disquisitions, and would not readily comprehend either the

language or the diagrams commonly used by scientific writers to

explain the phaenomena in question, I shall take pains to express

myself in the most familiar manner, and to use such comparisons

for illustration as may easily be understood.

If small leaden bullets, or large goose shot, be mixed with peas,

and the whole well shaken in a bushel, the shot will separate

from the peas, and will take its place at the bottom of the

bushel; forcing by its greater weight the peas which are lighter,

to move upwards, contrary to their natural tendency, and take

their places above.

If water and linseed oil, which is lighter than water, be mixed

in a vessel by shaking them together, upon suffering this mixture

to remain quite, the water will descend and occupy the bottom of

the vessel, and the oil, being forced out of its place by the

greater pressure downwards of the heavier liquid, will be obliged

to rise and swim on the surface of the water.

If a bottle containing linseed oil be plunged in water with its

mouth upwards, and open, the oil will ascent out of the bottle,

and passing upwards through the mass of water, in a continued

stream, will spread itself over its surface.

In like manner when two fluids of any kind, of different densities,

come into contact, or are mixed with each other, that which is

the lightest will be forced upwards by that which is the

heaviest.

And as heat rarefies all bodies, fluids as well as solids, air as

well as water, or mercury,--it follows that two portions of the

same fluid, at different temperatures, being brought into contact

with each other, that portion which is the hottest being more

rarefied or specifically LIGHTER than that which is colder, must

be forced upwards by this last.--And this is what always happens

in fact.

When hot water and cold water are mixed, the hottest part of the

mixture will be found to be at the surface above;--and when cold

air is admitted into a warmed room, it will always be found to

take its place at the bottom of the room, the warmer air being in

part expelled, and in part forced upwards to the top of the room.

Both air and water being transparent and colourless fluids,

their internal motions are not easily discovered by the sight,

and when these motions are very slow, they make no impression

whatever on any of our senses, consequently they cannot be

detected by us without the aid of some mechanical contrivance:--

But where we have reason to think that those motions exist,

means should be sought, and may often be found, for rendering

them perceptible.

If a bottle containing hot water tinged with log-wood, or any

other colouring drug, be immersed, with its mouth open,

and upwards, into a deep glass jar filled with cold water,

the ascent of the hot water from the bottle through the mass of

cold water will be perfectly visible through the glass.--

Now nothing can be more evident than that both of these fluids are

forced, or PUSHED, and not DRAWN upwards.--Smoke is frequently

said to be drawn up the Chimney;--and that a Chimney draws well,

or ill;--but these are careless expressions, and lead to very

erroneous ideas respecting the cause of the ascent of Smoke;

and consequently tend to prevent the progress of improvements in

the management of fires.--The experiment just mentioned with the

coloured water is very striking and beautiful, and it is well

calculated to give a just idea of the cause of the ascent of

Smoke. The cold water in the jar, which, in consequence of its

superior weight or density, forces the heated and rarefied water

in the bottle to give place to it, and to move upwards out of

its way, may represent the cold air of the atmosphere, while the

rising column of coloured water will represent the column of

Smoke which ascends from a fire.

If Smoke required a Chimney to DRAW it upwards, how happens it

that Smoke rises from a fire which is made in the open air,

where there is no Chimney?

If a tube, open at both ends, and of such a length that its upper

end be below the surface of the cold water in the jar, be held

vertically over the mouth of the bottle which contains the hot

coloured water, the hot water will rise up through it, just a

smoke rises in a Chimney.

If the tube be previously heated before it is plunged into the

cold water, the ascent of the hot coloured water will be

facilitated and accelerated, in like manner as Smoke is known to

rise with greater facility in a Chimney which is hot, than in one

in which no fire has been made for a long time.--But in neither

of these cases can it, with any propriety, be said, that the hot

water is DRAWN up the tube.--The hotter the water in the bottle

is, and the colder that in the jar, the greater will be the

velocity with which the hot water will be forced up through the

tube; and the same holds of the ascent of hot Smoke in a

Chimney.--When the fire is intense, and the weather very cold,

the ascent of the Smoke is very rapid; and under such

circumstances Chimneys seldom smoke.

As the cold water of the jar immediately surrounding the bottle

which contains the hot water, will be heated by the bottle while

the other parts of the water in the jar will remain cold, this

water so heated, becoming specifically lighter than that which

surrounds it, will be forced upwards; and if it finds its way

into the tube will rise up through it with the coloured hot

water.--The warmed air of a room heated by an open Chimney

Fire-place has always a tendency to rise, (if I may use that

inaccurate expression,) and finding its way into the Chimney

frequently goes off with the Smoke.

What has been said, will, I flatter myself, be sufficient to

explain and illustrate, in a clear and satisfactory manner,

the cause of the ascent of Smoke; and just ideas upon that subject

are absolutely necessary in order to judge, with certainty,

of the merit of any scheme proposed for the improvement of

Fire-places; or to take effectual measures, in all cases,

for curing smoking Chimnies.--For though the perpetual changes

and alterations which are produced by accident, whim, and caprice,

do sometimes lead to useful discoveries, yet the progress of

improvement under such guidance must be exceedingly slow,

fluctuating, and uncertain.

As to the causes of the smoking of Chimnies, they are very

numerous, and various; but as a general idea of them may be

acquired from what has already been said upon that subject in

various parts of this Essay, and as they may, in all cases,

(a very few only excepted,) be completely remedied by making the

alterations in Fire-places here pointed out; I do not think it

necessary to enumerate them all in this place, or to enter into

those long details and investigations which would be required to

show the precise manner in which each of them operates, either

alone, or in conjunction with others.

There is however one cause of smoking Chimnies which I think it

is necessary to mention more particularly.--In modern built

houses, where the doors and windows are generally made to close

with such accuracy that no crevice is left for the passage of the

air from without, the Chimnies in rooms adjoining to each other,

or connected by close passages, are frequently found to affect

each other, and this is easy to be accounted for.--When there is

a fire burning in one of the Chimnies, as the air necessary to

supply the current up the Chimney where the fire burns cannot be

had in sufficient quantities from without, through the very small

crevices of the doors and windows, the air in the room becomes

rarefied, not by heat, but by subtraction of that portion of air

which is employed in keeping up the fire, or supporting the

combustion of the fuel, and in consequence of this rarefaction,

its elasticity is diminished, and being at last overcome by the

pressure of the external air of the atmosphere, this external air

rushes into the room by the only passage left for it, namely, by

the open Chimney of the neighbouring room:--And the flow of air

into the Fire-place, and up the Chimney where the fire is burning

being constant, this expence of air is supplied by a continued

current down the other Chimney.

If an attempt be made to light fires in both Chimnies at the same

time, it will be found to be very difficult to get the fires to

burn, and the rooms will both be filled with Smoke.

One of the fires,--that which is made in the Chimney where the

construction of the Fire-place is best adapted to facilitate the

ascent of the Smoke,--or if both Fire-places are on the same

construction,--that which has the wind most favourable, or in

which the fire happens to be soonest kindled,--will overcome the

other, and cause its Smoke to be beat back into the room by the

cold air which descends through the Chimney.--The most obvious

remedy in this case is to provide for the supply of fresh air

necessary for keeping up the fires by opening a passage for the

external air into the room by a shorter road than down one of the

Chimnies; and when this is done, both Chimnies will be found to

be effectually cured.

But Chimnies so circumstanced may very frequently be prevented

from smoking even without opening any new passage for the

external air, merely by diminishing the draught, (as it is

called,) up the Chimnies; which can best be done by altering

both Fire-places upon the principles recommended and fully

explained in the foregoing Chapters of this Essay.

Should the doors and windows of a room be closed with so much

nicety as to leave no crevices by which a supply of air can enter

sufficient for maintaining the fire, AFTER THE CURRENT OF AIR UP

THE CHIMNEY HAS BEEN DIMINISHED AS MUCH AS POSSIBLE BY

DIMINISHING THE THROAT OF THE FIRE-PLACE; in that case there

would be no other way of preventing the Chimney from smoking but

by opening a passage for the admission of fresh air from

without;--but this, I believe, will very seldom be found to be

the case.

A case more frequently to be met with is where currents of air

set down Chimnies in consequence of a diminution and rarefaction

of the air in a room, occasioned by the doors of the room opening

into passages or courts where the air is rarefied by the action

of some particular winds. In such cases the evil may be

remedied, either by causing the doors in question to close more

accurately,--or, (which will be still more effectual,) by giving

a supply of air to the passage or court which wants it, by some

other way.

Where the top of a Chimney is commanded by high buildings, by

clifts, or by high grounds, it will frequently happen, in windy

weather, that the eddies formed in the atmosphere by these

obstacles will blow down the Chimney, and beat down the smoke

into the room.--This it is true will be much less likely to

happen when the throat of the Chimney is contracted and properly

formed than when it is left quite open, and the Fire-place badly

constructed; but as it is POSSIBLE that a Chimney may be so

much exposed to these eddies in very high winds as to be made to

smoke sometimes when the wind blows with violence from a certain

quarter, it is necessary to show how the effects of those eddies

may be prevented.

Various mechanical contrivances have been imagined for

preventing 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 prevent 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 description are all those Chimney-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 contrivances

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

complicated machinery, is to cover the top of the Chimney with a

hollow truncated pyramid or cone, the diameter of which above, or

opening for the passage of the Smoke, is about 10 or 11 inches.

--This pyramid, or cone, (for either will answer,)--should be of

earthen ware, or of cast iron;--its perpendicular height may be

equal to the diameter of its opening above, and the diameter of

its opening below equal to three times its height.--It should be

placed upon the top of the Chimney, 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 contrivance is, that the winds and eddies

which strike against the oblique surface of these covers may be

reflected upwards instead of blowing down the Chimney.--

The invention is by no means new, but it has not hitherto been

often put in practice.--As often as I have seen it tried it has

been found to be of use; I cannot 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 NEIGHBOURHOOD OF THE FIRE-PLACE little more

will be necessary to be done at the top of the Chimney than to

leave it open.

I cannot conclude this Essay without again recommending, in the

strongest manner, a careful attention to the management of fires

in open Chimnies; for not only the quantity of heat produced on

the combustion of fuel depends much on the manner in which the

fire is managed, but even of the heat actually generated a very

small part only will be saved, or usefully employed, when the

fire is made in a careless and slovenly manner.

In lighting a coal fire more wood should be employed than is

commonly 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 increase the fire to its proper

size[3].

The enormous waste of fuel in London may be estimated by the vast

dark cloud which continually hangs over this great metropolis,

and frequently overshadows the whole country, far and wide;

for this dense cloud is certainly composed almost entirely of

UNCONSUMED COAL, which having stolen wings from the innumerable

fires of this great city 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 atmosphere in its

descent, and frequently changing the brightest 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

compute the immense number of chaldrons of coals of which it is

composed; 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 little attention.

Conclusion.

Though the saving of fuel which will result from the improvements

in the forms of CHIMNEY FIRE-PLACES here recommended will be very

considerable, yet I hope to be able to show in a future Essay,

that still greater savings may be made, and more important

advantages derived from the introduction of improvements I shall

propose in KITCHEN FIRE-PLACES.

I hope likewise to be able to show in an Essay on COTTAGE FIRE-PLACES,

which I am now preparing for publication, that THREE QUARTERS,

at least, of the fuel which cottagers now consume in cooking their

victuals, and in warming their dwellings, may with great ease,

and without any expensive apparatus, be saved.

END OF THE FOURTH ESSAY.

EXPLANATION OF THE FIGURES

Essays; Political, Economical, and Philosophical — Volume 1 · 第 11 / 12 章

These directions are so clear, that it is hardly possible to