It is thus that coke, though somewhat mo_A Practical Treatise on Gas-light Exhibiting a Summary Description of the Apparatus and Machinery Best Calculated for Illuminating Streets, Houses, and Manufactories, with Carburetted Hydrogen, or Coal-Gas, with Remarks on the Utility, Safety, and General Nature of this new Branch of Civil Economy.

common coal, always gives out a more steady, a more lasting, and a more

intense heat.

The only inconveniences that attend the use of coke is, that, as it

consumes, it leaves much more ashes than common coal, charcoal, or wood;

and these much heavier too, which are, therefore, liable to collect in

such quantity as to obstruct the free passage of air through the fire;

and further, that when the heat is _very intense_, these ashes are

disposed to melt or vitrify into a tenacious drossy substance, which

clogs the grate, the sides of the furnace and the vessels. This last

inconvenience is only troublesome, however, when the heat required is

very great. In ordinary heats, such as are produced by kitchen or

parlour grates, the ashes do not melt, and though they are more copious

and heavy than those of charcoal or wood, they do not choke up the

fire, unless the bars of the grate be too close together.

The relative effects of heat produced by coke and coal are as follows:--

Six hundred pounds of pit-coal are capable of evaporating 10 cubic feet

of water in 20 hours, and 430lb. of coke are capable of evaporating 17

cubic feet of water in 12 hours and a half.[28]

[28] In order to learn the relative effect of different kinds of fuel,

with regard to their capability of producing heat, chemistry teaches

that equal quantities of fuel alike expended, will raise the

temperature of a given quantity of water through the same number of

degrees; whence, by knowing the original quantity and temperature of

water, together with the quantity of fuel expended to raise the water

to the boiling point, the result sought may be expressed by stating

the quantity of water at 30 degrees, which would have been raised 180

degrees by one pound of the fuel employed; or in the form of a rule,

Multiply the quantity of water by the number expressing the degrees

actually raised; multiply the number of pounds of fuel expended by 180

degrees. Divide the first product by the latter, and the quotient will

express the water which would have been raised 180 degrees by one

pound of the fuel. Or equal quantities of water may be compleatly

evaporated under equal surfaces and circumstances, with the different

kinds of fuel, the nature of which is to be examined; the quantities

of fuel expended for that purpose give the relative effect of the

different kinds of fuel, with regard to their power of producing

heat.

The Earl of Dundonald has shown that, in the application for burning

lime, a quantity of coke uniformly burns a given portion of lime-stone

in one-third part of the time that the quantity of coal from which the

coke had been made could do.

This effect is to be accounted for from having previously freed the

coal, or rather its coke, from the moisture and the tar, which it sends

out during combustion, and which condenses on the middle and upper

strata of stratified limestone and coal in the lime kiln, and impedes

the whole mass of materials from coming into a rapid and compleat

ignition; because the greater the quantity of materials, and the sooner

the whole is ignited, the better and more economically the lime is

burned, both as to coals and time; the saving of which last is a

material object, especially at lime-kilns where there is in the summer

time a great demand for lime, the coke occasioning the kilns to hold a

_third more lime_ at the _same time_.

In the art of making bricks, in the smelting of metallic ores, and the

drying of malt, the advantages of coke over coal, are sufficiently

known.

The following account given by Mr. Davis,[29] shows that the advantages

that may be derived in the processes of burning lime, plaster of paris,

and bricks, by means of coke, are greater than at first sight might be

imagined.

[29] Philosophical Magazine, Vol. 33, p. 435.

“The coke obtained in the gas process is so valuable, that it appears

inexplicable that men should not avail themselves of this mode of

procuring light, to the almost total exclusion of all other methods now

in use. As a landholder, placed among an industrious but wholly

illiterate society of men, I have had the more opportunity of trying

this species of fuel or coke, which I could not otherwise procure in

this sequestered spot, at a tolerably cheap rate, for purposes to which

it has not, as far as I know, been hitherto employed. I must tell you

that I am my own lime-burner, plaster of paris baker, and brick-maker;

and that in these processes of rural economy I have derived the greatest

benefits from this species of fuel, which I now prepare at a cheap rate,

although I waste almost the whole of the light of the coal gas

intentionally. The coal which I employed formerly for the burning of

limestone into lime, is a very inferior kind of small coal, called here

Welsh culm. The kiln for burning the limestone into lime is a cup-shaped

concavity, surrounded with solid brick-work, open at the top, and

terminating below by an iron grate. It has a stone door that may be

opened and closed for charging and emptying the furnace when required.

This furnace I formerly charged with alternate strata or layers of small

coal and limestone, the latter being broken previously into pieces not

larger than a man’s fist, until the kiln was completely filled. The

stone is thus slowly decomposed; the upper part of the charge descends,

and when it has arrived at the bottom of the furnace new strata are

super-imposed, so as to keep the furnace continually full during a

period of 50 hours. The quantity of lime I procured with small coal

formerly amounted to 85 bushels. The strata of coal necessary for the

production of this quantity of lime require to be four inches thick, and

the time necessary for calcination was, as stated already, 50 hours.

“On applying coke instead of coal, the produce of lime may be increased

to nearly 30 per cent. from the same furnace, and the time required to

effect the calcination of this quantity of lime-stone is reduced to 39

hours: it also requires _less attendance_ and _less labour_, and the

whole saving, thus accomplished, amounts to more than 50 _per cent. on

the lime-kiln_.

“I have lately also employed coke for the burning of bricks. My bricks

are burnt in clamps, made of bricks themselves. The place for the fuel,

or fire-place, is perpendicular, about three feet high. The flues are

formed by gathering or arching the bricks over, so as to leave a space

between each of a brick’s breadth; and as the whole of the coal, if this

fuel be employed, must, on account of the construction of the pile, be

put in at once, the charge of the bricks is not, and never can be, burnt

properly throughout; and the interference of the legislature, with

regard to the measurement of the clamp, is a sufficient inducement for

the manufacturer to allow no more space for coal than he can possibly

spare.

“If coke be applied instead of coal, the arches, or empty spaces in the

clamp or pile, as well as the strata of the fuel, may be considerably

smaller: the heat produced in this case is more uniform and more

intense, and a saving of 30 per cent. at least is gained.

“In the baking my own plaster-stone I also employ coke. The calcination

of the stone for manure I perform in a common reverberatory furnace, and

the men who conduct the process (who are otherwise averse to every thing

new) are much pleased with the steadiness of the fire, and little

attendance which the process requires, when coke is used instead of

coal.

“These are the few facts I wish to state, with regard to the useful

application of this species of fuel, which, no doubt, hereafter will

become an object of economy of incalculable advantage to individuals, if

its nature be better understood than it is at present.”

The quantity of coke obtainable from a given quantity of coal varies

according to the nature of the coal employed. One chaldron of Newcastle

coal produced, upon an average, in the gas-light manufacture, from one

chaldron and a quarter to one chaldron and a half of well formed coke.

If the carbonization of the coal has been carried to its utmost point,

the coke produced, has a brilliant silvery lustre. Such coke is

excellent for metallurgical operations, because it stands the powerful

blast of the bellows, but for culinary and other purposes of domestic

economy, the carbonization should not be carried so far, because, the

coke then produced, kindles more readily and makes a more cheerful fire.

_Coal-tar_, _Oil_, and _Pitch_.--Another, valuable product obtainable

from pit-coal, is coal-tar.[30] This substance is deposited, in the

purification of the coal-gas, in a separate vessel destined to receive

it.

[30] In the year 1665, Becher, a German chemist, brought to England

his discovery for extracting tar from coal, this distillation he

performed in close vessels. It is not mentioned in the records of the

time, whether Becher obtained, or rather collected, any other articles

than the tar.

The coal-tar is so called from its resembling common tar in its

appearance, and most of its qualities.

Several works have been, at different times, erected both in England and

on the continent, to procure from coal a substitute for tar; but they

turned out unprofitable speculations. In 1781, the Earl of Dundonald

invented a mode of distilling coal in the large way, which enabled him

not only to form coke, but, at the same time, to save and collect the

tar. Even this process however, for which a patent was taken out, has

gained very little ground. Its object was still too limited; for though

some of the ingredients of coal were procured, they were procured at an

expense that nearly balanced the profits; and no attention whatever was

paid to the coal gas, which constitutes the most important part of coal.

Coal-tar may be used with advantage for painting and securing wood that

is exposed to the action of air or water. The wood being warmed, the tar

is applied cold, and penetrating into the pores, gives the timber an

uncommon degree of hardness and durability.

One chaldron of Newcastle coal produces in the gas-light manufacture

from 150 to 180lb of tar, according to the circumstances under which it

is produced. See page 94.

The tar obtained from Newcastle coal-tar is specifically heavier than

that produced from cannel-coal; hence it sinks in water, whereas the

latter swims on the surface of that fluid.

To render the tar fit for use, it requires to be evaporated to give it a

sufficient consistence. If this process be performed in close vessels,

a portion of an essential oil is obtained, which is known to colourmen

by the name of oil of tar. To obtain this oil, a common still is filled

with the coal-tar, and, being properly luted, the fire is kindled and

kept up very moderate, for the tar is very apt to boil up in the early

part of the process. The first product that distils over is principally

a brown ammoniacal fluid, mixed however with a good deal of oil. As the

process advances, and the heat is increased, the quantity of ammoniacal

liquor lessens, and that of oil increases, and towards the end of the

distillation the product is chiefly oil.

The oil and ammoniacal water which distil over do not mix, so that they

may be easily separated by decantation. The oil is a yellowish inferior

kind of oil of turpentine, which is very useful in painting ships, for

making varnishes, and other coarse out-door work.

Two hundred pounds of tar produce, upon an average, fifty-three pounds

of essential oil.

If the coal-tar is wanted to be converted into pitch, without obtaining

the oil which it is capable of furnishing, the evaporation of it may be

performed in a common boiler; but as it is extremely liable to boil

over, the greatest precaution is necessary in conducting the

evaporation. A boiler constructed on the following plan is very

convenient for the conversion of coal-tar into pitch. The contrivance

consists in adding a spout, or rim, to the common boiler, into which the

tar spreads itself as it rises, and by this means becomes cooled, and

the boiling over is checked.

[Illustration: _Kettle for boiling Tar._]

1000lb. of coal-tar produce, upon an average, from 460 to 480lb. of

pitch. A subsequent fusion, with a gentle heat, converts the coal-pitch

into a substance possessing all the characters of _asphaltum_.

_Ammoniacal Fluid._--The properties of the ammoniacal liquor, which

accompanies the tar, and which is deposited in the tar-cistern, has not

yet been fully investigated. It is employed already in the manufacture

of muriate of ammonia (sal ammoniac). One chaldron of coal affords from

220 to 240lb. of this ammoniacal fluid, which is composed chiefly of

sulphate, and carbonate of ammonia.--Such are the products obtainable

from coal.

However certain the practicability of extending the new lights to the

dwelling houses of every town and village is, it cannot be expected that

such an event should take place speedily and generally. To eradicate

prejudice, and to alter established habits, is a work which nothing but

time can effect; because prejudice is the effect of habit, and can

seldom be eradicated from the minds of such individuals as consider the

ready occurrence of a proposition as a test of its truth. To establish a

new philosophical theory has, in every instance, required time

sufficient to educate an entire generation of men. The rejection of the

Aristotelian philosophy--the adoption of experimental research--the

substitution of the doctrine of gravitation instead of that of vortices,

and the rejection of phlogiston by modern chemists, are sufficiently

illustrative of this assertion. New arts, and new practices, are still

more difficult to be introduced. The new art of bleaching need merely be

mentioned to prove this assertion. The new grammar--the new rudiments of

science--the new stile--or the new instrument, however superior to the

old in simplicity, facility, and truth, must be less valuable to the

ordinary teacher or artisan, whose memory is familiarized with the

precepts of the latter, and whose only ambition is to earn his

subsistence with the least possible exertion.

The slowness with which improvements of every kind, make their way into

common use, and especially such discoveries as are most calculated to be

of an extended or general utility is very remarkable, and forms a

striking contrast to the extreme avidity with which those unmeaning

changes are adopted, which folly and caprice are continually sending

forth into the world under the auspices of _fashion_.

On the first view of the subject it appears very extraordinary, that any

person should neglect, or refuse to avail himself of a proposed

invention, or improvement, which is evidently calculated to economise

his labour, and to encrease his comforts; but when we reflect on the

power of habit, and consider how difficult it is for a person even to

perceive the disadvantages or imperfections of former modes to which he

has been accustomed from his early youth, our surprize will be

diminished, or vanish altogether.

Many other circumstances, besides prejudice, are unfavourable to the

introduction of new and useful discoveries. Among these jealousy,

malice, envy, and revenge, have too often their share in obstructing the

progress of real improvement, and in preventing the adoption of plans

evidently calculated to promote the public good.

A plan like the present, which proposes not only to trench upon domestic

habits, but to give an entire new direction to a portion of the skill

and capital of the country, must necessarily encounter the most

strenuous opposition. It is thus that some individuals have mustered all

their strength against the introduction of this new art. An endeavour

has been made to move the public opinion by dismal forebodings of the

Greenland trade, and the subsequent loss of a nursery of British seamen.

This objection is nothing more than the common clamour that is always

set up against every new means of abridging labour, to which had the

public listened, an interdict would have been laid upon the spinning and

threshing machines, the steam engine, and a thousand other improvements

in machinery.

Indeed such clamour scarcely ever fails to be made when the extension of

machinery and the abridgement of labour or the application of inanimate

powers are considered. On such occasions, it is stated by certain humane

but mistaken objectors, that the scheme of mechanical and chemical

improvement is pointed against the human species--that it tends to drive

them out of the system of beneficial employment--that the introduction

of machinery is injurious to the labouring class of society, by

abridging their work. Two creatures offer themselves for employment and

support--a man and a horse. I must invariably prefer the latter, and

leave the former to starve. Two other beings--a horse and a

steam-engine, are candidates for my favour. My preference to the latter

tends to exterminate the species of the former. In both cases it is

stated, that the number of intelligent creatures capable of the

enjoyment of happiness must be diminished for want of support; and that,

on the whole, the sum of the proposed improvement is not only a less

proportion of good to society, but a positive accession of misery to the

unemployed poor.

On this wide and extended argument, which can in fact be maintained

against all improvements whatever in no other way than by insisting that

the savage state of man, with all its wants, its ignorance, its

ferocity, and its privations, is preferable to the social intercourse of

effort and division of labour we are habituated to prefer, it may be

sufficient to observe that it includes matter not only for reasoning and

induction, but also for experiment. By reference to the matter of fact,

though it must be allowed that new improvements, which change the habits

of the poor, must at first expose them to a temporary inconvenience and

distress, against which, in fairness, it is the duty of society to

defend them; yet the invariable result of such improvements is always to

better the condition of mankind. A temporary inconvenience to

individuals must often be incurred for the sake of general national

benefit.

It is to manufactories carried on by machinery and to the abridgment of

labour, that this country is indebted for her riches, her independence

and pre-eminent station among the nations of the world.

But let us return to the subject.--The progress of the new mode of

lighting with coal-gas can never wholly supersede the use of candles and

moveable lights. The objection with regard to the Greenland trade is

equally futile. This traffic, might with more propriety be called a

drain, than a nursery, of the naval force. The nature of the Greenland

service requires that the crew should consist chiefly of able-bodied

sailors; and being protected men, not subject to the impress law, they

are thus rendered useless for national defence. The nursery of British

seamen is the coasting trade; and if the gas-light illumination be put

in practice to a large extent, it will increase that trade as much as it

will diminish the Greenland fishery.

Even on the extreme supposition that it would annihilate the Greenland

fisheries altogether, we should have no reason to regret the event. The

soundest principles of political economy must condemn the practice of

fitting out vessels to navigate the polar seas for oil, if we can

extract a superior material for procuring light at a cheaper rate from

the produce of our own soil.

Indeed the fisheries will find ample encouragement, and the consequence

of lighting our streets with gas can prove injurious only to our

continental friends, one of whose staple commodities, tallow, we shall

then have less occasion to purchase.

There will be less waste indeed, but a greater consumption of coal. The

lower classes of the community are at present very scantily supplied

with firing; and nothing but a reduction of price is necessary to

increase to a very large amount the whole average quantity of fuel

consumed in the country. The lightness of the coke produced in the

gas-light manufacture diminishing the expence of land carriage, will

facilitate its general diffusion--the comforts of the poor will be

materially augmented, and a number of useful operations in agriculture

and the arts be carried on, which are now checked and impeded by the

price of fuel.

If any additional want were wanted for the coke it will readily be

found in the continental market; coke being much better suited than coal

to the habits of most European nations.

The gas-light illumination cannot tend to diminish the coal-trade; on

the contrary it will prove beneficial to it; it will contribute to lower

the price of the superior kinds of coal, and keep a level which cannot

be shaken under any circumstances; it will contribute to prevent

combinations which do certainly operate to the prejudice of the public,

and do sometimes put this great town at the mercy of particular

proprietors in the north, who deal out coal in the way they please. The

competition thus produced, it is impossible not to consider as an

advantage, which would prevent in future such combinations, and put

those in London out of the reach of them.

It is worthy observation, that the annual importation of coal into this

Metropolis, is above one million and eighty-eight thousand

chaldrons.[31]

[31] To give an idea how long there is a probability of Great Britain

being applied with coal from the rivers Tyne and Wear only, it must be

observed,

_1st_. That the Seams of coal which are now worked at Newcastle and

Sunderland, are equal to a seam or bed of 15 miles by 20 miles.

_2dly_. That this seam, on an average, is at least four feet and a

half thick.

_3dly_, That 1-6th part of the above extent is sufficient for pillars

to support the roofs of the mines, &c.

And, _4thly_, It appears, by experiments, that a cubic yard of coal

weighs 1 ton, or 20 cwt.

London Chaldrons

The total consumption of coal from the rivers Tyne

and Wear known from the register to be 2,300,000

The number of tons in the above quantity taking the

London chaldron at 27 cwt. is 3,100,000

Now a ton weight of coal is estimated to occupy in

the earth the space of one cubic yard.

The number of cubic yards in the square mile is 3,097,600

The beds or seams of coal are, on an average, 4

feet and a half in thickness, which increases the

above number of cubic yards in the square mile by

half the number of square yards to 1,548,800

And hence the square mile of the beds or seams of

coal we are describing contains, of cubic yards

and tons of coal 4,645,000

A deduction of 1-6th for pillars to support the

mine, &c. 800,000

The number of tons per square mile 5,445,000

We have already mentioned the length and breadth of the seams of coal

to be equal to 20 miles by 15, making an area of 300 square miles, and

consequently a source of consumption for 375 years.

It may be objected to the universality of our conclusion, that the price

of coals, differing very much in different places, will occasion a

variation in the expence of the new mode of illumination. But there are

two reasons why this should have less place, because we find, in Mr.

Murdoch’s statement, page 69, that of 600l. the estimated yearly expence

of lighting the cotton mill, 550l. consist of interest of capital, and

tear and wear of apparatus, leaving the cost of coal only 50l. a sum so

trifling, when we reflect that it replaces 2000l. worth of candles, that

the price of coal, even where it is highest, can but slightly affect the

general profits.[32]

[32] See, also, Mr. Ackermann’s statement, page 71.

_2dly_, The coal, by yielding the gas and other products,--namely, tar,

pitch, ammoniacal liquor, &c. of which we have treated already, is

converted into a substance, increased in bulk, and in the power of

producing heat, namely, coke; and as a manufactory generally requires

heating as well as lighting, there will be a gain both ways. The

manufacturer, by distilling his coal, instead of burning it as it comes

from the pit, will save his candles and improve his fuel. One effort at

the outset, in erecting a proper apparatus, will reduce his annual

disbursement, for these two articles of prime necessity, much in the

same manner, (though in a far greater degree) as the farmer gains by

building a thrashing machine and laying aside the use of the flail.

The principal expence in the pursuit of this branch of civil and

domestic economy is therefore the dead capital employed in erecting the

machinery destined for preparing and conveying the gas; the floating or

live capital is comparatively small. At the same time, were we to offer

an advice to the public on this subject, it would be, that no private

individual resident in London should attempt to light his premises for

the sake of economy with coal-gas by means of his own apparatus, whose

annual expence for light does not exceed 60l. because the expence of

erecting and attending a small apparatus is almost as great as one

constructed on a larger scale would be. For if the quantity of gas

wanted is not sufficient to keep the retorts continually in a red-hot or

working state, the cost of the gas will be considerably enhanced;

because either the empty retorts must be continued red-hot, or the fire

must be suffered to go out; and the retorts, when cold, cannot be

brought to a working state, that is to say, be made red hot again, but

at a considerable expence of fuel, which must be wasted to no purpose.

Whereas, if the retorts are constantly kept red hot and in action, one

half of the coal necessary to produce a given quantity of gas will then

be saved. But when a street, or a small neighbourhood is wanted to be

lighted, and the retorts can always be kept in a working state, that is

to say, red hot, the operation may be commenced with safety; because the

sum required for erecting the apparatus, and the labour attending it,

together with the interest of money sunk, will then soon be liquidated

by the light which it will afford.

Individuals, therefore, may engage in the distillation of coal, and

trade with advantage in the articles produced by that process, and the

lighting of cities may be accomplished without the aid of incorporated

bodies; and parishes may be lighted by almost as many individuals as

there are streets in a parish.

From experiments, made by Mr. CLEGG, on the effects produced by a number

of gas-lights, of a certain intensity, there is reason to believe that

the streets of small towns might be illuminated at a cheaper rate, by

means of a tower, or pagoda, furnished with gas-lamps, than can be done

in the ordinary way by street lamps: the gas being conducted to the top

of the building from the apparatus below, and the light directed down

again, upon the objects to be illuminated, by means of reflectors placed

at a certain angle. By this contrivance, all the main pipes which convey

the gas through the streets, as well as those collateral ones that

branch out from them to the street lamps, would be saved, and thus

compensate for the expense of the tower.

The most beneficial application of gas-lights unquestionably is in all

those situations where a great quantity of light is wanted in a small

place: and where light is required to be most diffused, the advantages

of this mode of illumination are the least.--Hence, as already stated,

the lighting of the parish, or street-lamps only, without lighting shops

or houses, can never be accomplished with economy.

We have noticed before the reason why the price of coals can have little

effect upon the gas-light; because the very refuse, or small coals,

called slack, which pass through the screen at the pit’s mouth, and

which cannot be brought into the market--nay, even the sweepings of the

pit, which are thrown away, may be employed for the production of

coal-gas. It makes no difference in what form the coal is used, and this

circumstance may contribute to enable the coal-merchant to furnish coals

in larger masses, and as they come from the mine, instead of increasing

the bulk by breaking them into a smaller size,[33] which is a practice

commonly adhered to. This unquestionably reduces the value of coals;

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

given quantity of any kind of fuel depends 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: most of the heat

produced will then be expended in giving elasticity to a thick dense

vapour, or smoke, which is seen rising from the fire; and the combustion

being very incomplete, the carburetted hidrogen gas of the coal being

driven up the chimney without being inflamed, the fuel is wasted to

little purpose.

[33] It is not generally apprehended, how very wasteful the use of

small coals is in the ordinary open fire-grates. Necessity makes us

use the poker very much, particularly, when the coals are small; and

habit prevails even when they are large. By the constant stirring of

the fire almost the whole of the small coal passes through the bars;

and consequently a great deal goes to the dust-hole without being

burnt at all. To prove this, we need only take a shovel full of ashes

and put them into a pail, and then pouring water over them, which

being gently run off, will carry away nearly all the light and burnt

parts: and leave an astonishing quantity of bright unburnt coal, which

has escaped from the fire-place, in consequence of being small.

When the grate of the fire-place is large, and the small coals are

thrown behind; or when we can have patience enough to bear the cold

for an hour or two, or contrive to have the fire lighted a long time

before we want it, the small coal may be of some use, but the fire

made with it is never strong, nor so bright; and does not burn so long

as a fire made with large or round coals: it often requires the help

of the poker, and produces a great quantity of breeze.

The loss in the use of small coals is more considerable to the poor,

who cannot keep large fires. When they want their breakfast or dinner,

the time they can spare is limited; and to have their water sooner

boiling, or their meals quicker ready; they must make use of the

poker, and lose a great deal of coal. This fact is so evident, that

any body who wishes to make the experiment before recommended, will

find that much more bright coal goes to the dust-hole of the poor man,

than to the dust-hole of a rich family, where, the fire-place being

large, the small coal has more chance of burning.

The loss is still greater to the poor, in consequence of the inferior

sorts of coal which are sold to them. If it is the light sort, it

burns too quick, and they consume double the quantity; if the strong

sort, it burns too slow, and is nearly as wasteful; for a great

quantity of it then goes to the dust-hole without having been lighted

at all.

An incorrect opinion is often entertained, that the real quantity of

coal contained in a sack is lessened by separating or screening the

small from the round coals; but we must recollect, that any compact

body occupies less space than is required to contain the same matter,

reduced to smaller irregular pieces, or to powder.--Now the screening

only takes away the finest dusty part of the coals, and admits more

small pieces of round coals to be filled into the sack.

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

slovenly at the same time, than the manner in which chimney fires, where

coals are burnt, are commonly managed by servants. They throw on a load

of (perhaps all small) coals at once, through which the flame is hours

in making its way; and frequently it is not without much care and

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 heating power, 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 the coal-gas is ignited. And it happens not unfrequently, especially

in chimnies 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 and aqueous vapour which escapes 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,

or to prevent them becoming quickly heated, so as to give out the

carburetted hidrogen gas which they are capable of furnishing, and to

cause it to be inflamed, In short, a fire should never be smothered: and

when attention is paid to the quantity of coals put on, there is little

use for the poker; and this circumstance will contribute much to

cleanliness, and the preservation of furniture.

The author of a paper in the Plain Dealer asserts, that, of the various

perversions of abilities, there is none that makes a human being more

ridiculous, than that of attempting to stir a fire without judgment; to

prevent which he lays down the following rules:--1. Stirring of a fire

is of use, because it makes a hollow where, the air being rarefied by

the adjacent heat, the surrounding air rushes into this hollow, and

gives life and support to the fire, and carries the flame with it. 2.

Never stir a fire when fresh coals are laid on, particularly when they

are very small, because they immediately fall into the hollow place, and

therefore ruin the fire. 3. Always keep the bottom bars clear. 4. Never

begin to stir the fire at the top, unless when the bottom is quite

clear, and the top only wants breaking.

There is one subject more on which it is necessary to speak.--In the

present instance, the public has been alarmed by representations that

the general adoption of gas-lights would expose us to innumerable

accidents, from the inflammable nature of the gas, and the explosion of

the apparatus in which it is prepared, or the bursting of the pipes by

which it is conveyed. But there is no ground for such fears.

Those who are familiar with the subject will readily allow, that there

is no more risk in the action of a gas-light machinery, properly

constructed, than there is in the action of a steam-engine, built on

just principles.

The manufacture of the coal-gas requires nothing more than what the most

ignorant person, with a common degree of care and attention, is

competent to perform. The heating of the gas-furnace, the charging of

the retorts with coal, the closing them up air-tight, the keeping them

red-hot, and discharging them again, are the only operations required in

this art; and these, surely, demand no more skill than a few practical

lessons can teach to the meanest capacity. The workman is not called

upon to exercise his own judgment, because, when the fire is properly

managed, the evolution of the gas goes on spontaneously, and without

further care, till all the gas is extricated from the coal.

No part of the machinery is liable to be out of order,--there are no

cocks to be turned, no valves to be regulated; nor can the operator

derange the apparatus but by the most violent efforts. And when the

stock of gas is prepared, we may depend on its lighting power as much

as we depend on the light to be obtained from a certain number of

candles or oil-lamps.

The diversified experiments which have been made by different

individuals, unconnected with each other, have sufficiently established

the perfect safety of the new lights; and numerous manufactories might

be named in which the gas-lights have now been in use for upwards of

seven years, where nothing like an accident has occurred, though the

apparatus in all of them is entrusted to the most ignorant man.

It would be easy to state the causes which have given rise to some of

those accidents that have spread alarm amongst the public; but of this

it is not my business to speak at length. It is sufficient, on the

present occasion, to state, that those melancholy occurrences which have

happened at some gas-light establishments which I have had an

opportunity of examining, were totally occasioned by egregious failures

committed in the construction of the machinery. Thus, an explosion very

lately took place in a manufactory lighted with coal-gas, in consequence

of a large quantity of gas escaping into a building, where it mingled

with common air, and was set on fire by the approach of a lighted

candle. That such an accident could happen, is an evident proof that the

machinery was erected by a bungler, unacquainted with the most essential

principles of this art; because such an accident might have been

effectually prevented, by adapting a waste pipe to the gasometer and

gasometer house. By this means, if more gas had been prepared than the

gasometer would contain, the superfluous quantity could never have

accumulated, but would have been transported out of the building into

the open air, in as an effectual manner as the waste-pipe of a water

cistern conveys away the superfluous quantity of water, when the cistern

is full. Such an expedient did not form part of the machinery.

Other instances might be named, where explosions have been occasioned

through egregious mistakes having been committed in the erection of the

gas-light machinery, were this a subject on which I meant to treat.

That the coal-gas, when mixed with a certain portion of common air, in

close vessels, may be inflamed by the contact of a lighted body, as has

been stated, page 98, is a fact sufficiently known. But the means of

preventing such an occurrence in the common application of gas-lights,

are so simple, easy, and effectual, that it would be ridiculous to dread

danger where there is nothing to be apprehended. In speaking thus of the

safety of the gas-light illumination, I do not mean to deny that no

possible circumstances may occur where the coal-gas may be the cause of

accident. It is certain that the gas, when suffered to accumulate in

large quantities in close and confined places, where there is no current

of air, such as in cellars, vaults, &c. and where it can mix with common

air, and remain undisturbed, that it may be liable to take fire when

approached by a lighted body; but I do not see how it is probable that

such an accumulation of gas should take place in the apartments of

dwelling houses. The constant current of air which passes continually

through the rooms, is sufficient to prevent the possibility of such an

accumulation ever to take place. And with regard to the bursting of the

pipes which convey the gas, no accident can possibly happen from that

quarter; because the gas which passes through the whole range of pipes

sustains a pressure equal to the perpendicular weight of about one inch

of water only, and such a weight of course is insufficient to burst iron

pipes. Nor could the town when illuminated by gas-lights, be thrown

suddenly into darkness, as has been asserted might happen by the

fracture of a main pipe, supposing such an event should take place;

because the lateral branches, which supply the street-lamps and houses,

are supplied by more than one main; and the consequence of a fracture

would be only an extinction of the few lamps in the immediate vicinity

of the broken pipe, because the rest of the pipes, situated beyond the

fracture, would continue to be supplied with gas from the other mains,

as will become obvious from the sketch exhibited in the next page.

[Illustration: Main pipe, leading from the Gas-light station or

apparatus, situated in Brick Lane, near Old St.[34]

Main pipe, leading from the gaslight apparatus, or station, at Norton

Falgate.[35]

Main pipe, leading from the gaslight apparatus, or station, in

Westminster.[36]]

[34] _The gasometer at this place is equal in capacity to 22000 cubic

feet._

[35] _The capacity of the gasometer here is equal to 15928 cubic

feet._

[36] _At this station the gasometer is equal in capacity to 14808

cubic feet._

The black lines represent the gas-light mains, or largest pipes, from

which the smaller pipes branch off: they are connected with each other

at the places marked A B C; and the dotted lines represent the smaller

mains, or collateral branches before-mentioned. The main pipes are all

furnished with valves, or cocks, placed at about 100 feet distant from

each other. Now let us suppose that a main pipe, in any part of the

street marked in the sketch, _Pall Mall_, should break, it is evident,

on mere inspection, that the gas which is passing through the main in

the _Strand_, and which is also connected with the main in the

_Haymarket_, _Piccadilly_, and _Coventry Street_, would continue to

supply the broken pipe, and the valve nearest to the fracture being

shut, would prevent the loss of any considerable quantity of gas, and

the few lamps situated between the two valves and the fracture would

therefore only become extinguished.

Further, let us suppose a main pipe should break in _Piccadilly_; in

that case, the valve being shut on each side of the fracture, the gas

would be supplied from the mains in the _Haymarket_ and _St. James’s

Street_. And the same effect would be produced in any part of the town,

supplied with gas-pipes. Besides all this, in the statement thus far

given, we have assumed that all the gas-light mains are supplied with

gas from one manufacturing station only, but which in reality is not the

case. The range of pipes that convey the gas is connected with three

gas-light establishments, situated at different parts of the town; and

the gas which is supplied from these stations is connected with the

whole system of pipes in the streets.[37] If, therefore, one of the

manufactories should be annihilated, it would make no difference,

because the lights would be amply supplied from the other two

manufacturing stations. Hence it is obvious, that the fracture of any of

the gas-light mains, or even the total destruction of one or more of the

manufactories themselves, would be attended with no serious consequence;

and as the system of lighting with gas becomes more extended, the

manufactories, or stations for supplying it, will also be multiplied, to

give effect and security to the whole.

[37] As shown in the sketch.

In fact, no danger can arise from the application of gas-lights in any

way, but what is common to candle-light, and lamps of all kinds, and is

the fault of none of them. Even in this case the gas-lights are less

hazardous. There is no risk of those accidents which often happen from

the guttering or burning down of candles, or from carelessly snuffing

them. The gas-light lamps and burners must necessarily be fixed to one

place, and therefore cannot fall, or otherwise become deranged, without

being immediately extinguished. Besides, the gas-light flames emit no

sparks, nor are any embers detached from them. As a proof of the

comparative safety of the gas-lights, it need only be stated, that the

Fire-offices engage themselves to insure cotton-mills, and other public

works, at a less premium, where gas-lights are used, than in the case of

any other lights.[38] The excessive expence of insurance arising from

the numerous candles employed in most of the first rate manufactories,

and the combustible nature of the structure of the buildings; the great

difficulty of retrieving the injury resulting to a well-organised

business, from the accidental destruction of the machinery, are objects

alone sufficient to furnish the strongest economical, as well as

political recommendations, for the adoption of the new lights in all

manufactories where work is done by candle-light.

[38] Since the preceding pages have been printed, I have seen a

_self-extinguishing gas-lamp_, invented by Mr. CLEGG. This lamp is so

constructed, that the gas cannot flow to the burner, when the flame

becomes extinguished. If, therefore, the lamp should be blown out, and

the stop-cock which supplies the gas be left open, the extinction of

the flame will effectually shut the valve. The action of this lamp

depends upon the expansibility of a metallic rod, heated by the flame

of the lamp, and thus keeping open the valve, whereas, when the lamp

is extinguished, and the rod becomes cold, it contracts to its natural

dimensions, and, by that means, effectually closes the valve. The same

engineer has invented a machine, which both measures and registers, in

the absence of the observer, the quantity of gas delivered by any pipe

communicating with a gas-light main. The machine occupies a space of

about two feet by one foot, and, if put up in a room, house, or other

place, where gas is burnt, will, at any time, by mere inspection, give

an account of the quantity of gas consumed in that place during any

given time. On the present occasion, it would not become me to say

more on these subjects, which, no doubt, Mr. CLEGG will make known to

the public; I shall only remark, that these contrivances do signal

honour to the talents and abilities of the inventor; and that they

will render the greatest services to those who are engaged in the

gas-light illumination.

After considering the facts so far detailed, many other advantages,

connected with the gas-light illumination, will naturally suggest

themselves to the reader. I have endeavoured merely to point out the

leading characters of the new lights, as they are at present. Ingenious

men may speculate from what has been done to what remains to be

effected, which, no doubt, will embrace objects of the greatest utility

and most extended national importance. The public attention is awakened

to the new properties of coal, and will not rest till they are

extensively applied to economical purposes. The consequence will be, a

considerable defalcation in the revenue. For, in proportion as the

gas-lights are more or less generally adopted in all towns of the

country, the consumption of oil and tallow will be diminished, and the

impost on those articles become less productive; and when this takes

place, Government, no doubt, will share in the profits, by levying a tax

on the new lights. The Exchequer will thus have nothing to fear; as one

branch of the revenue fails, another, and a more productive one, will

supply its place.

Upon the whole, when we reflect that the object of the gas-light

illumination is to open a source of national wealth, of which nothing

can deprive us, to create, we may almost say, new articles of value, its

friends cannot be thought guilty of great presumption, if they look

forward with confidence to the successful extension of this new art of

civil economy; and if, contrary to all expectations, the effects of

jealousy and prejudice should, in some respect or other, continue here

and there its influence against this new art of procuring light, a firm

perseverance of its application must at length remove that ignorance

which alone can give them birth.

TABULAR VIEW, EXHIBITING

The quantity of GAS, COKE, TAR, PITCH, ESSENTIAL OIL, and AMMONIACAL

LIQUOR, obtainable from a given quantity of COAL; together with an

Estimate of the quantity of Coal necessary to produce a quantity of

Gas, capable of yielding a Light equal in duration of time and

intensity to that produced by Tallow Candles of different kinds.

-----------+------------------------------------------

| _Cost of Coal._

| Minimum. Maximum. Average.

-----------+------------------------------------------

One Chal. }|

of Coal, }| 40_s_ to 60_s_ -- 50_s_

from 25 to}|

28 cwt. }|

One Ton | 30_s_ to 48_s_ -- 38_s_ 6_d_

One Sack | 3_s_ 4_d_ to 5_s_ -- 4_s_ 2_d_

One Bushel | 1_s_ 2_d_ to 1_s_ 8_d_ -- 1_s_ 5_d_

One Peck | 3½ to 5_d_ -- 4¼

One Pound | ¼

-----------+------------------------------------------

-----------+-----------------------------------

| _Weight of Coal._

| Min. Max. Aver.

-----------+-----------------------------------

One Chal. }|

of Coal, }| 2,800 to 3,136 -- 2,968

from 25 to}|

28 cwt. }|

One Ton | 2,240

One Sack | 233 to 261 -- 247

One Bushel | 78 to 87 -- 82½

One Peck | 19½ to 21¼ -- 20¼

One Pound | 1

-----------+-----------------------------------

-----------+--------------------------------

|_Produce of Gas, in cubic feet._

| Min. Max. Aver.

-----------+--------------------------------

One Chal. }|

of Coal, }| 8,906 to 11,872 10,388[39]

from 25 to}|

28 cwt. }|

One Ton | 6,720 to 8,960 -- 7,840

One Sack | 741 to 988 -- 814

One Bushel | 247 to 330 -- 290

One Peck | 61 to 82 -- 71½

One Pound | 3 to 4 -- 3½

-----------+--------------------------------

-----------+-----------------------------------------

| } |_Candles._

| } |9,516 11 to the pound.

One Chal. }| }[39]Equal to |8,651 10 do.

of Coal, }| }as many tallow |7,786 9 do.

from 25 to}| }candles, 12 in |6,921 8 do.

28 cwt. }| }the pound, |6,556 7 do.

| }burning two |5,194 6 do.

One Ton | }hours; or to |4,325 5 do.

One Sack | } |3,463 4 do.

One Bushel | } |2,595 3 do.

One Peck | } |1,730 2 do.

One Pound | } | 866 1 do.

-----------+-----------------------------------------

COKE.--One chaldron of coal, from 25 to 28 cwt. gives 1¼ to 1½

chaldron of Coke.

TAR.--One chaldron of coal, from 25 to 28 cwt. gives from 150 to

180lb. of Tar,[39] or 15 to 18 ale gallons, 10lb. each.

AMMONIACAL LIQUOR.--One chaldron of coal, gives from 220 to 240lb. of

Ammoniacal Liquor, or 22 to 24 ale gallons.

[39] 1000lb. of Coal-Tar afford by distillation, from 260 to 265lb.

of Essential Oil, or Naphtha. 1000lb. of Coal-Tar produce by mere

evaporation, from 460 to 480lb. of Pitch.

_Tabular View, exhibiting the illuminating power of Coal-Gas, compared

with the illuminating power of Tallow Candles of different sizes._

One chaldron of Coal produces, according to weight and quality,

Cubic feet of Gas. Average. Burning. Candles. 12 to 1lb. 6 to 1lb.

From 9,000 to 12,000 10,500 1 hour = 21,000 = 10,500

----- ------ ------ 2 hours = 10,500 = 5,250

6,000 8,000 7,000 3 ditto = 7,000 = 3,500

4,500 6,000 5,250 4 ditto = 5,250 = 2,625

3,600 4,800 4,400 5 ditto = 4,400 = 2,200

3,000 4,000 3,500 6 ditto = 3,500 = 1,750

2,571 3,428 3,005 7 ditto = 3,005 = 1,502

2,250 3,000 2,625 8 ditto = 2,625 = 1,312

2,000 2,666 2,333 9 ditto = 2,333 = 1,166

1,800 2,100 2,100 10 ditto = 2,100 = 1,050

1,636 2,191 1,913 11 ditto = 1,913 = 956

1,500 2,000 1,750 12 ditto = 1,750 = 875

1,384 1,846 1,615 13 ditto = 1,615 = 807

1,285 1,714 1,499 14 ditto = 1,499 = 749

1,200 1,600 1,400 15 ditto = 1,400 = 700

1,125 1,500 1,312 16 ditto = 1,312 = 656

1,058 1,111 1,234 17 ditto = 1,234 = 617

1,000 1,333 1,166 18 ditto = 1,166 = 583

947 1,263 1,105 19 ditto = 1,105 = 552

900 1,200 1,050 20 ditto = 1,050 = 525

857 1,143 1,000 21 ditto = 1,000 = 500

818 1,095 956 22 ditto = 956 = 478

783 1,044 913 23 ditto = 913 = 456

750 1,000 875 21 ditto = 875 = 437

N. B. If it be required to know, for how many hours one pound, or one

peck, or one bushel, or one sack, of coal will produce Gas Light equal

to that of a certain number of well-snuffed Tallow Candles, the

proportion of each of the average weights of a pound, peck, bushel, or

sack, to that of the average weight of a chaldron of coal, is as

follows:

1 lb. = 2968th part of a chaldron.

One peck 20 = 148th ditto.

One bushel 82 = 36th ditto.

One sack 248 = 12th ditto.

RULE.--Divide with either of the above parts of weight, the number of

lights opposite to their hours, and the product will be the number of

lights burning for the same number of hours.

EXAMPLE.--To know how many lights one peck of coal will give for six

hours, divide the 148th part in 3,500, opposite to the number of six

hours, the product is almost 24 lights. The same rule holds good for any

given quantity or number of pounds of coal, in a chaldron, to find how

many lights, or candles, 12 to the lb. or 6 to the lb. they will give

for a given number of hours.

DESCRIPTION OF THE GAS-LIGHT APPARATUS.

PLATE I.

Exhibits a perspective view of a gas-light apparatus,[40] for lighting

factories, or small districts of houses. It consists of the following

parts: which may be considered separately.

[40] This apparatus was erected by Mr. CLEGG, and is now in action at

Mr. ACKERMAN’s establishment, in this metropolis.

FIG. 1. The _Retort Furnace_, for distilling the coals. It is built of

brick-work. The bricks which are exposed to the immediate action of the

fire, are _Welch tumps_, or fire-bricks; they are bedded in clay, or

Windsor loam.

FIG. 2. The _Tar Cistern_, to collect the coal-tar, and other

condensible products obtained during the distillation of the coals. It

is a cast-iron hollow cylinder, closed at the top with a cast-iron

cover, which has a very small hole to allow the air to escape as the

liquid enters into the vessel.

FIG. 3. The _Lime Machine_, for purifying the crude coal-gas, and to

render it fit for use. The construction of this machine will be

explained in plate VII. It is put together of cast-iron plates.

FIG. 4. The _Gasometer_, for collecting and preserving the purified gas,

and for distributing and applying it as occasion may require. It

consists of two principal parts--namely, a large interior vessel closed

at the top and open at the bottom, made of sheet iron, designed to

contain the gas, and an outer cistern or vessel, of rather greater

capacity, constructed of cast-iron plates, in which the former vessel is

suspended. The latter contains the water by which the gas is confined.

The interior vessel which contains the gas is suspended by chains hung

over wheels or pullies, to which weights are attached, so as to be just

sufficient to balance the weight of the gasometer, all but a small

difference, and allowing its slow descent in the manner which is found

as nearly adapted as can be to the proper supply of the lamps. The

weight of the chains must be equal to the specific gravity of the

material of which the gasometer is composed, so as to compensate

accurately for the quantity of water which the gasometer displaces, or

what is the same, it must be equal to the loss of weight which the

gasometer sustains, when immersed in the water; and the counterpoise

weight must be equal (or nearly so) to the absolute weight of the

gasometer.

The action of these different parts of the apparatus will be obvious

from the following explanation:

A, A, are two iron retorts, placed horizontally, and side by side, in

the furnace; the mouth of the retorts where the coals are introduced,

projects into an arched chamber, situated in front of the furnace, as

shewn in the drawing by the broken down brick-work. The object of

suffering the mouth of the retorts to project into a separate chamber,

is merely to discharge with convenience the red hot coke from the

retorts when the process is at an end; the coke being suffered to fall

to the bottom of the chamber, where it cools, without becoming

troublesome to the operator. It may be removed from this fire-safe

chamber by the door represented at the end view of the furnace.

When the operation commences, the inner vessel of the gasometer, fig. 4

is sunk down, to expel the air which it contains to a level with the

exterior vessel, or outer cistern, of the gasometer; and, consequently,

becomes filled with water. As the distillation of the coal in the

retorts proceeds, the liquid and gazeous products evolved from the coals

are transmitted by means of the perpendicular syphon pipes B, B, into

the horizontal pipe or main condenser C, with which they are connected.

The liquid which is distilled, collects in the pipe, or main condenser,

C, where it is retained until its quantity has risen so high as to

discharge itself into the pipe D, which is connected with the upper part

of one of the extremities of the condenser, C. One of the extremities of

the pipes, B, B, therefore become immersed into the liquid contained in

the main condenser or pipe C, whilst the vaporous or condensible fluid,

after having overcome the pressure there opposed to it, is transported

into the pipe E, which, after passing in a serpentine direction, E, E,

&c. through the exterior vessel or cistern of the gasometer, terminates

in the tar-vessel, fig. 2. Thus the vaporous fluids are condensed by

passing through the serpentine pipe, E, E, &c. and become deposited in

the tar-cistern, fig. 2; whilst the non-condensible or gazeous products

are made to proceed by the pipe F, which branches off from the pipe E,

into the lime machine, fig. 3. In this apparatus the gas, as it is

evolved from the coals, comes into contact with slaked lime and water;

the object of which is, to strip it of its sulphuretted hydrogen and

carbonic acid gas with which it always abounds, and to render it fit for

illumination. This being accomplished, the purified gas is conducted

away out of the lime machine by means of the pipe G, into the

perpendicular pipe H, which branches up through the bottom of the

gasometer cistern. The upper extremity of this pipe is covered, in the

manner of a hood, by a cylindrical vessel I, open at bottom, but

partially immersed beneath the surface of the water contained in the

outer cistern of the gasometer, it is also perforated round near the

lower edge with a number of small holes. The gas, as it passes out of

the pipe H, displaces the water from the receiver I, and escapes through

the small holes, and is thus made to pass through the water in the

cistern, in which the hood of the pipe I, is partly immersed, so as to

expose a large surface to its action, that it may once more be washed,

and deprived of all the foreign gazeous products which might have

escaped the action of the lime, whilst it was agitated with this

substance in the lime machine, fig. 3. After rising through the water in

the gasometer cistern, it enters into the gasometer, which then ascends

as the gas accumulates in it.

In this manner the process proceeds, until the whole of the volatile

products of the coal in the retort are disengaged. The use of the

gasometer is, partly to equalize the evolution of the gas which comes

from the retort more quickly at some time than others. When this

happens, the vessel rises up to receive it, and when the stream from the

retort diminishes, the weight of the gasometer expels its contents,

provided the main-cock be open. When the process is finished, the retort

is suffered to cool, and its lid is then removed to replenish it with

coal. When the main stop-cock is then opened, the gasometer descends,

and the gas passes from the gasometer through the pipe K, to the

burners, or main pipe, which communicates with the gas burners or lamps.

L, is a wooden tub or barrel, containing the mixture of lime and water,

for charging the lime machine; and into which the contents of the

barrel, L, may be conveyed by the curved pipe M, without admitting

common air. N, N, is a water-pipe, to convey fresh water into the

gasometer cistern occasionally; because it is essential that the water

used for washing and purifying the gas should be changed for fresh as

soon as it becomes dirty; and unless this is done, the gas will not be

perfectly purified by washing, but produce a disagreeable odour when

burnt; the same holds good with regard to the lime machine, the

contents of which should be renewed occasionally. This pipe also conveys

the necessary water into the barrel, L. O, is a waste-pipe, to convey

the water as it becomes impregnated with the impurities of the gas, out

of the gasometer cistern. P, is an agitator, to stir up the contents of

the lime machine occasionally, Q, Q, are two iron rods, which serve as

stays to guide the motion of the gasometer. R, is an index, connected by

means of a shaft and pulley with the axis of one of the gasometer

wheels. This index is graduated to the capacity of the cubical contents

of the gasometer, so as to indicate, by the rising and falling of the

gasometer, its relative contents of gas expressed in cubic feet. S, is

the waste pipe of the lime machine, to remove the insoluble parts of the

lime. T, represents the iron cover, or lid, which is turned on the

lathe, and ground air-tight, to close up the mouth of the retort, so as

to make readily an air-tight fitting. U is an iron wedge to secure the

cover of the retort. The left-hand retort in the design shows the retort

closed up, and the cover, or lid of the mouth of it secured by means of

the wedge, in its place, so as to render the mouth of the retort

perfectly air tight.

There is a safety valve attached to this gasometer which could not be

represented in the drawing; and the object of which is, to convey away

any portion of gas that might happen to be produced by a careless

operator, when the gasometer is full, and which is thus prevented from

accumulating in the place where the gasometer is erected. It is

represented in the right-hand corner of plate VII. where fig. 1 shows

the edge of the gasometer; 2, the surface of the water in the inside of

the gasometer; 3, the surface of the water in the outside of the

gasometer, or in the cistern; 4, a pipe issuing from the lower edge of

the gasometer, and surrounded at its upper extremity with a cup marked

5; 6, the waste pipe, the mouth of which is immersed in water. It is

obvious that, when the gasometer is full, if an additional quantity of

gas should be attempted to be put into it, it will be transported by

means of the pipe 4, into the waste-pipe 6; the upper extremity of which

reaches out of the building, and there communicates with the open air.

PLATE II.

Represents a Portable experimental Gas Apparatus for exhibiting, in the

small way, the general nature of the gas-light illumination.--It is

described page 79.

PLATES III. IV. V.

Show designs of various kinds of Gas Lamps, Chandeliers, Candelabras,

&c.--See pages 114, 118, 140.

PLATE VI.

FIG. 1. Exhibits a design of the _gasometer framing_, or _skeleton_,

which serves to give stability and strength to the gasometer. It

consists of wooden frame work, marked A, A, A, interlaced with iron

rods, B, B, B, &c. The whole framing is so disposed that it will float

in the cistern horizontally, and therefore keep the gasometer perfectly

steady and level with the surface of the water.

The rest of the sketches represent various kinds of gas pipes employed

as _mains_ for conveying the gas, and the methods of connecting them.

FIG. 2. Represents a longitudinal section of a _Spigot_ and _Faucet

Pipe_. These kinds of pipes are applicable in most cases as mains for

conveying gas. A, is called the spigot, and B, the faucet. They are

joined together, and made air tight, by iron cement, the composition of

which is as follows:

Take two ounces of sal ammoniac, one ounce of flowers of sulphur, and

sixteen ounces of cast iron filings or borings. Mix all well together,

by rubbing them in a mortar, and keep the powder dry.

When the cement is wanted for use, take one part of the above powder,

and twenty parts of clean iron borings or filings, and blend them

intimately by grinding them in a mortar. Wet the compound with water,

and when brought to a convenient consistence, apply it to the joints

with a wooden or blunt iron spatula.

By a play of affinities, which those who are at all acquainted with

chemistry will be at no loss to comprehend, a degree of action and

re-action takes place among the ingredients, and between them and the

iron surfaces, which at last causes the whole to unite as one mass. In

fact, after a time, the mixture and the surfaces of the flanches become

a species of pyrites (holding a very large proportion of iron,) all the

parts of which cohere strongly together.

The inner parts of the faucet ought to be no larger in diameter than

just to fit the spigot. This supports the pipe, independently of the

cement, and prevents the risk of hurting the joint from any external

stress. The inner faucet is commonly made about 2½ inches deep, and has

the spigot inserted 1½ inch into it. The practice of some workmen, is to

make the outer faucet, or that which contains the cement, six inches

deep, for all pipes above six inches diameter; and to make the faucets

of all pipes below six inches, the same depth as the diameter of the

pipes. It is usual to make the space for the cement, all round the

spigot, from 1 to 1½ inch; that width is required, in order that the

cement may be firmly driven into the joint. When the space is very

narrow, this cannot be done. On the other hand, when too wide, there is

a waste of cement, and a risk of injury from unequal expansion.

FIG. 3. Exhibits a profile view of these kinds of pipes when joined

together. The spigot and faucet pipes are liable to burst from the great

expansion of the spigot, and the risk of this accident is increased by

increasing the space between the spigot and faucet, which requires to be

filled with cement.

FIG. 4. Represents a longitudinal section of two flanch pipes, and the

modes of connecting them. A and B, show the parts of the pipes; and C

and D, the flanches. These pipes are also joined together, and rendered

air-tight, by interposing between the flanches rope-yarn, hemp, or some

other pliable material, and iron cement, and then screwing up the faces

of them by means of the bolts and screw nuts.

FIG. 5. Profile view of the same kind of pipes connected together, A and

B, the pipes; C and D, the flanches; E and F, the bolts.

FIG. 6. Represents the method of joining spigot and faucet pipes when

they are to have a turn or angle. This method is convenient when the

place where the turn required to be made is previously known, and the

pipes cast accordingly.

FIG. 7. Exhibits the method of connecting spigot and faucet pipes when

they have a round turn. A and B, the junctures of the pipes.

FIG. 8. Represents a longitudinal section of the mode of joining pipes

by means of what is called a _thimble joint_. The junctures of the pipes

to be connected, are made air tight, as mentioned already, by iron

cement. A, the thimble or small cylinder, with projecting edges, which

unites the pipes B, C.

FIG. 9. A thimble joint made in two parts, which is sometimes convenient

to join pipes. The parts are joined together by screw bolts, and nuts,

in the usual manner.

FIG. 10. Section of the same.

FIG. 11. Represents a profile view of what is called the _saddle joint_.

It is employed for taking off a branch-pipe. The branch has a piece A B,

formed on its end, and fits round one-half of the outside of the pipe

from which it is to proceed. C, is called the saddle, which fits round

the other half of the pipe. The parts are secured together by screw

bolts, and iron cement. By this method a branch may be formed on any

part of a gas-pipe, by cutting a hole there, and applying the branch to

that place. Where there is much risk of the inequality of expansion, the

joints at certain places, should be secured by a soft stuffing of hemp

and tallow; but in most cases the joints may be made with iron cement.

Lead is frequently used for making the joints of gas pipes instead of

iron cement, though cheaper and more easy of repair. The galvanic action

which takes place between the lead and iron, soon renders the joints

leaky, and the danger is increased by the unequal expansion of the two

metals.

FIG. 12. Section of the saddle-joint.

Before the gas is suffered to enter into the pipe, they should be proved

to be sound, by the usual process of forcing water into them: The pipes

serving as mains, are placed perfectly solid, so that they cannot give

way; their course should be rectilinear, having a descent of about 1

inch in 9 or 10 feet, to allow the water of condensation which may be

deposited from the gas by a change of temperature to collect readily at

the lowermost part.

FIG. 13. Shows a reservoir for collecting the water of condensation

which might accumulate in the pipes. It consists of a receptacle, A, in

which the water may pass; B, a branch-pipe closed at the top, by means

of which the water may be removed, by drawing it out with a syringe.

This receptacle is placed in those situations where pipes incline

towards each other.

PLATE VII.

Exhibits a perpendicular section of a gas-light apparatus, calculated

for lighting towns, or large districts of streets and houses.

FIG. 1. The Retort Furnace. The retorts are placed over each other in

one or more rows; so that a certain number of them may be heated by

separate fire-places. A, A, shows two of the retorts placed horizontally

above each other; B, the fire-place; C, the flue which causes the fire

to circulate round the retorts so as to heat them equally in every part;

D, the opening of the flue where the fire passes into the chimney; E,

the ash-pit; F, a chamber in front of the retort furnace, into which the

orifice or mouth of the retorts project; G, G, the doors of the chamber,

to enable the workmen to charge and discharge the retorts; H, a funnel

shaped hole at the floor of the chamber F, through which the red hot

coke as it is discharged from the retorts passes into the arched vault

I; K, the syphon tube; L, the horizontal condenser[41]--the action of

both of these pipes have been already explained, p. 168; M, main pipe,

which conveys the liquid substances from the condenser, to the tar

cistern, fig. 3, and which conducts also the gazeous products into the

lime machine, fig. 2; N N, shows that part of the pipe which is

interposed between the tar cistern, fig. 3, and the condensing pipe

M,--it passes in a serpentine direction along the inner sides of the

gasometer cistern, and, like the so-called _worm_ in a distillatory

apparatus, condenses the products which escape in a vaporous state from

the condenser L; O, shows the place where the serpentine pipe N N,

passes again out of the gasometer cistern, and its communication with

the lime machine, fig. 2, and tar chamber, fig. 3. The action of the

lime machine is as follows: The liquid products evolved from the coal,

having been deposited in the tar cistern, fig. 3, by means of the

serpentine pipe N, N, the gazeous products which accompany it, are

conveyed by means of the pipe P, which branches out from the pipe O,

into the interior receptacle of the lime machine marked Q, which

consists of a vessel open at the bottom, and closed at the top, where it

communicates with the pipe O. As the gas accumulates in the interior

part Q, of the lime machine, it is made to pass through the liquid which

it contains, namely, slaked lime and water; and escapes through

appertures made in the horizontal partitions R, R, R, R, into the outer

vessel, S, of the lime machine and from thence it is conducted away by

the pipe T, T, T, into the additional washing apparatus, of the

gasometer; fig. 4, the construction of this apparatus, greatly resembles

the lime machine, fig. 2, namely, V, is a water pipe, proceeding from a

cistern U, placed 3 or 4 feet above the orifice of the pipe V; T, T, is

the gas-pipe, covered with a hood, marked W, and immersed in a small

cistern, having horizontal perforated shelves, like those in the lime

machine--they fit close to the hood. The gas which enters the hood W,

meets with a shower of water delivered by the pipe V. The gas, as it

passes through the holes in the horizontal partitions, is, therefore,

again washed and thoroughly purified from foreign gases which may have

escaped the action of the lime machine; Y, is a waste pipe, the lower

extremity of which is sealed by being immersed in water,--it serves to

carry away the water delivered by the pipe V, as it has been acted on by

the gas. The summary action of this gas apparatus is, therefore, as

follows: The liquid products obtained from the coal during the

distillation are first deposited in the main condenser L, by means of

the pipe K, and from whence they cannot escape until a quantity of tar

has accumulated in it to a certain height, and by this means, one of the

extremities of the pipes K, K, becomes immersed and hermetically sealed

by the liquid which the condenser L, contains. The liquid products,

after having accumulated to a certain height in the condenser, overflow

the perpendicular portion which it contains, and discharge themselves

into the pipe M, from whence they are transported into the tar cistern,

fig. 3, by means of the system of pipes N, N, O, whilst the gazeous

products are made to pass by means of the branch pipe P, into the lime

machine, fig. 2. From this part of the apparatus the gas passes through

the pipe T, T, T, into the additional or smaller washing apparatus

placed upon a tressel in the cistern of the gasometer, where it is

again exposed a second time to the action of a current of fresh water;

and from this vessel the gas ascends into the gasometer. The gasometer

is furnished with a pipe A, closed at the top, and fixed in one corner

of the gasometer, but open at the bottom; it includes another pipe

marked B, which communicates with the main pipe leading to the burners,

or place where the gas is wanted. The pipe A, which slides over the pipe

B, is perforated at the top, the gas passes through these perforations

and is thus made to enter into the pipe B, and disposed of as mentioned.

C, C, is a tube of safety adapted to the gasometer; its lower extremity

remains sealed by the water in the cistern so long as the gasometer is

not overcharged with gas; but, if more gas should be made to enter the

gasometer than it is destined to receive, this pipe then delivers the

gas into the funnel-shaped tube D, which reaches through the roof of the

gasometer house, and thus the superfluous quantity of gas is conveyed

away into the open air.

[41] The condenser in this apparatus is placed at right angles to the

row, or rows of retorts. It is furnished at one extremity with a

partition placed perpendicularly, and of a height equal to about

one-half of the diameter of the condenser. The object of this

partition is to prevent the tar, &c. deposited in it, to seal the

pipes K, K, and not to discharge itself into the pipe M, till this has

been effected. The partition is seen in the drawing.

The cylindrical vessel P, of fig. 3, surrounding the orifice of the pipe

O, which delivers the tar into the tar cistern, fig. 3, serves to keep

this pipe constantly immersed into a portion of tar, so that the

contents of the cistern may be drawn off by the cock without admitting

air into any part of the apparatus. The tar cistern has a small hole at

the top, to allow the air which it encloses to escape, as it becomes

filled with tar and ammoniacal liquor. The main condenser L, is placed,

as shown in the drawing, higher than the level of the water in the

gasometer cistern, to allow a free descent of the distillatory liquids

as they pass from this vessel along into the pipes M, N, O, &c. The

cistern of the gasometer, as well as the lime machine, and tar cistern,

are constructed of cast iron plates, bolted and cemented together with

iron cement. The gasometer is made of sheet iron plates rivetted

together--E, E, are two iron stays--G, G, are friction wheels.

_METHOD of correcting the relative pressure of the Gasometer, so as to

cause the gas which it contains to be uniformly of an equal

density._[42]

[42] For this elegant contrivance we are also indebted to Mr. CLEGG.

We have mentioned already that the pressure of the gas in the gasometer

should be invariable, for it is obvious that the weight of the gasometer

is constantly increasing in proportion as it fills with gas, and rises

out of the water--see p. 88, and 167. To render its pressure uniform, we

first take the _absolute_ weight of that part of the gasometer which

becomes immersed in the water, and knowing the _specific weight_ of the

substance of which it is composed, we divide its absolute weight by the

specific weight of the substance of which it is composed; and this being

done, we make part of the chain, (measured at right angles from the axis

of the wheels over which it passes downwards towards the top of the

gasometer,) which is equal to the length of that part of the gasometer

which becomes immersed in water, equal in weight to the specific gravity

of the substance of which the gasometer is composed. For example, let

us suppose that the part of the gasometer which becomes immersed in

water weighs 861 _lb._ and that it is composed of sheet iron, the

specific gravity of which, in round numbers, we will take to be 7. It is

then evident, that the part of the chain of the gasometer measured

downward from the axis of the wheel over which it passes, and which is

equal in length to the height of the gasometer, must be loaded with a

weight of, or must itself weigh, 123_lb._ for this would be the weight

of the water displaced by the gasometer; or let us suppose the gasometer

to be made of sheet copper, the specific weight of which (omitting

decimals) is 8; and that the absolute weight of the gasometer is

1792_lbs._ then the chain of the gasometer equal in length to the height

of the gasometer, immersed into the water must weigh 224_lb._ for this

would be the weight of the quantity of water which the gasometer

displaces. This being accomplished by then adding or diminishing the

absolute or balance weight of the gasometer, any desired uniform

pressure may be effected, and the same bulk of gas will always be of the

same specific gravity.

DIRECTIONS TO WORKMEN ATTENDING THE GAS-LIGHT APPARATUS[43].

[43] Copied from a printed direction drawn up by Mr. Clegg, for the

use of workmen.

Particular care must be taken to make the joints of the mouth-pieces of

the retorts perfectly air tight, which may be done in the following

manner:--Take some common clay, dry, pulverize, and sift it, then add

as much water as will make it into the consistency of treacle; make the

mouth-piece and the lid of the retort clean, lay this luting thinly over

the turned part of the lid, press the lid so luted gently to the

mouth-piece, and then secure it moderately, by means of the iron wedge:

if the workman observes this rule, he will never fail to make good

joints; but if, on the other hand, the operator is careless and neglects

to remove the old luting, &c. from the turned or smooth part of the

mouth of the retort, and thereby cause a bad joint, the consequence will

be the loss of a considerable quantity of gas, and a very disagreeable

smell and smoke.

The bridge or row of bricks of the flue C, of the retorts, should never

be made hotter than a bright red, which may be regulated by the door of

the ash-pit being kept close shut when the fire is getting too hot. If

the operator neglects this, and suffers the fire-bricks to arrive at a

bright white heat the retorts will soon be destroyed, and bad gas be

produced.

The gasometer should be well examined, at least once a week, to see if

it leaks, by the following method, viz. Let the main stop-cock be shut,

then make a mark on the gasometer at the water’s edge when it is full or

nearly of gas, there being no gas coming from the retorts at the time,

and if the mark sinks in the water, the gasometer leaks; to find out the

place, walk slowly round it, and you may perceive the leak by the smell,

apply a lighted candle to the part suspected, and if there be gas

issuing from it, it will take fire, and perhaps appear like a small

blue flame--blow it out, and mark the place: thus proceed round the

gasometer till you have found all the places; if you perceive a smell,

and yet cannot produce a flame in the part suspected, take a brush with

a little thin white-lead paint, and lay it on the part where you think

the leak is, and, if it be there, the gas which escapes from the leak,

will immediately turn the paint brown. After the sides of the gasometer

have been well examined, and secured by dipping a piece of cloth about

the size of a shilling, into some melted pitch, tempered with a little

bees-wax and tar, apply the cloth whilst hot to the place with the end

of your finger, rubbing it till it is quite cold; next examine the top

of the gasometer in the same manner,--when it is about two feet high in

the cistern, it will then be better to get at. The water in the cistern

should always be kept within 3 or four inches of the top, if suffered to

sink much lower without replenishing, the gas will not pass through a

sufficient quantity of water, and oily particles will be apt to condense

in the pipes, to their great detriment.

The only thing to be observed in the place lighted is, that the lamps

and pipes are not suffered to be touched on any pretence whatever, but

by the person entrusted with their care. When a lamp is not wanted, it

must be completely shut off from the pipe which supplies it, by a

stop-cock provided for the purpose, and not opened again but when a

flame is held over it; not a lighted candle, as the tallow is liable to

drop into the lamps; lighted paper is better.

ESTIMATE OF THE PRICE OF A GAS-LIGHT APPARATUS, _IF ERECTED IN LONDON_,

Capable of affording, every 24 hours, Light equal to 40,000 Tallow

Candles, six in the pound, burning one hour.

£. s.

Gasometer, to contain 10,000 cubic feet of gas 236 0

Wheel-work, regulating chain, ballance-weight for } 160 11

ditto, with wooden framing }

Wrought iron cistern for gasometer--36 feet wide, } 500 0

24 feet long and 16 feet deep }

(_It would weigh about 16 tons._)

Wooden framing built around it, to secure ditto 150 0

Condenser, cistern and communicating pipes 126 0

Lime machine, made of cast iron plates 82 0

Gasometer-house, built of frame-work and weather-boarded 250 0

Twenty-four retorts set in brick-work, with furnaces } 336 0

for ditto, compleat }

Sundries 100 0

---------

£ 1940 11

* * * * *

A gas-light apparatus complete for work, capable of affording every

twenty-four hours a quantity of light equal to 1,400 Argand’s Lamps,

each lamp equal in intensity to six candles, six in the pound, burning

for five hours, will cost 3,500_l._ if erected in this metropolis.

LONDON Price List of the most essential articles[44] employed in the

erection of a Gas-Light apparatus.

[44] All the articles are warranted to be perfect and of the best

kind. They are delivered free of expence at any wharf between London

and Westminster-bridge.

Sheet-iron pipes brazed.

_s._ _d._

¼ inch in diameter 0 4 a foot}

⅜ ditto 0 4 ditto}

½ ditto 0 5 ditto}

⅝ ditto 0 6 ditto}

¾ ditto 0 6½ ditto} in

⅞ ditto 7 ditto} 15

1 inch, ditto 0 7½ ditto} to

1¼ ditto 0 9 ditto} 18

1½ ditto 0 10½ ditto} feet

1¾ ditto 0 11 ditto} lengths.

2 inch, ditto 1 1½ ditto}

2¼ ditto 1 4 ditto}

2½ ditto 1 5 ditto}

3 inch, ditto 1 6½ ditto}

Copper pipes brazed ¼ inch 0 4 per foot

Ditto, ditto, ditto ⅜ inch 0 5½ ditto

Gas-light cockspur burners with stop-cock 2s 6d to 3s 6d

Argand’s lamps, with glass-holders, from 3s to 4s 6d

Cast-iron retorts, weighing 7 cwt. at 15s 6d per cwt £5 8 6

Mouth-piece for ditto, compleat 1 14 8

Cast-iron door frames for retort furnace 1 0 0

Furnace bars 10s. per cwt.

Sheet iron for gazometer (No. 23) 24s. per cwt.

Gazometer chains, 5d per lb.

Ballance weights [Plates] for gazometer, 9l 10s per ton.

Cast-iron cistern plates

------------------------ smaller size for lime machine, 18l per ton.

------------------------ middling size for tar cistern, 16l ditto

------------------------ largest size for gazometer cistern 14l ditto

Cast-iron flanch pipes 2-inch diameter, at 5s per yd. in 6 feet lengths

ditto 3 ditto 6s ditto 6 ditto

ditto 4 ditto 8s 6d ditto 9 ditto

ditto 5 ditto 10s ditto 9 ditto

ditto 6 ditto 12s ditto 9 ditto

ditto 7 ditto 13s 6d ditto 9 ditto

ditto 8}

ditto 9} 11l. 5s. per ton 9 ditto

ditto 10}

ditto 11}

½ inch nuts, screws and washers to put iron pipes together 7d. per lb

⅝ ditto 7d. ditto

¾ ditto 6d. ditto

English bar-iron 13l. per ton

Best, ditto 18l. ditto

_FINIS._

[Illustration: Fig. 1

_London Pub. April 1-1815, at R·Ackermann’s, 101 Strand._]

[Illustration]

Transcriber’s notes

The entries in the Table of Contents do not always conform to the

chapter and section headings in the text. Both have been retained as in

the original work.

The errata have already been incorporated in the text; the error

mentioned as occurring on page 24 actually occurs on page 22.

The original language, including inconsistencies in spelling,

hyphenation, punctuation, formatting, etc. has been retained, except as

mentioned below.

Unclear parts of the text have been checked against the on-line copy of

this book of the Eidgenössische Technische Hochschule Zürich.

Fractions like ½ and 1-10th have both been retained.

Page 90, Van Dieman, Troostwyck: Jan Rudolph Deiman and Adriaan Paets

van Troostwijk.

Changes made to the text:

Obvious punctuation and typographical errors have been corrected

silently.

Some footnotes, tables and illustrations have been moved; some tables

have been re-arranged.

Other changes:

Page 23: any surfaces changed to any surface

Page 26: opening or shuting changed to opening or shutting

Page 47: A New changed to A new

Page 48: trafic changed to traffic; footnote [10]: corporated changed to

incorporated (cf. errata)

Page 53: This combustion changed to The combustion (cf. errata)

Page 64: Cleg changed to Clegg (cf. errata); footnote anchor [14] moved

from next page (cf. errata, footnote anchor *); communicates changed to

communicated (cf. errata)

Page 67: 1250 + 2 = 2500 changed to 1250 × 2 = 2500

Page 69: Mr. LEE changed to “Mr. LEE for consistency

Page 72: closing quote mark added to letter

Page 96: pure coal- changed to pure coal-gas

Page 102: sub acetate changed to sub-acetate

Page 118: ball 6 changed to ball _b_

Page 119: _e_, are changed to _e_ _e_, are

Page 125: 180 degree changed to 180 degrees (cf. errata); footnote [28]:

may he compleatly changed to may be compleatly

Page 131: and make changed to and makes

Page 132: coal changed to coal-tar (cf. errata)

Page 158: Nortou Falgate changed to Norton Falgate; a about changed to

about

Page 165, table: 10,509 changed to 10,500.

A Practical Treatise on Gas-light Exhibiting a Summary Description of the Apparatus and Machinery Best Calculated for Illuminating Streets, Houses, and Manufactories, with Carburetted Hydrogen, or Coal-Gas, with Remarks on the Utility, Safety, and General Nature of this new Branch of Civil Economy. · 第 5 / 5 章

It is thus that coke, though somewhat more difficult of ignition than