UTILITYOF THEGAS-LIGHT ILLUMINATION,WITH REGARD TOPUBLIC AND PRIVATE ECONOMY.

[17]One chaldron of Newcastle coal weighs from 2850 to upwards of 2978lb.

The production of carburetted hydrogen, both with regard to quantity and quality from the same kind of coal depends much upon the degree of temperature employed in the distillatory process. If the tar and oil produced duringthe evolution of the gas in its nascent state, be made to come in contact with the sides of the red hot retorts, or if it be made to pass through an iron cylinder or other vessel heated red hot, a large portion becomes decomposed into carburetted hydrogen gas and olifiant gas, and thus a much larger quantity of gas is produced than would be obtained without such precaution from the same quantity of coal.[18]

[18]One pound of coal-tar produces 15 cubic feet of carburetted hidrogen abounding in olifiant gas.

The distillation of the coal, (if gas be the chief object) should therefore not be carried on too rapidly. Most of the retorts used in the large way, are calculated for containing about one hundred weight of coal, and in general, when previously heated, produce from two and one-half to three cubic feet of gas, in four hours for each pound of coal they contain; but when the layer of coals in them does not exceed four inches in depth, three and one-half to four feet of gas may be obtained in the same time.

The retorts best calculated for large gas-light works are seven or eight foot long (without the mouth-piece) and twelve inches in diameter,tapering down to ten inches—if they are larger the coal which they contain cannot be heated properly. The advantages that may be derived from the circumstances before stated are of greater value in the gas-light manufacture than is often imagined, and the quantity as well as the quality of the gas is very much influenced by such circumstances. If coal be distilled with a very low red heat scarcely observable by daylight, the gas produced gives a feeble light—if the temperature be increased so that the distillatory vessel is of a dull redness, the light is more brilliant and of a better colour—if a bright or cherry-red heat be employed the gas produced, burns with a brilliant white flame, and if the heat be increased so far that the retort is almost white hot, and consequently in danger of melting, the gas given out, has little illuminating power, and burns with a clear blueish flame;[19]or if the coal abounds in pyrites or sulphuret of iron, as is sometimes the case with Newcastle coal, a large quantity of sulphuretted hidrogen is likewise evolved, which although it increases the illuminating power of the coal-gas, has the capital disadvantage, of producingan intolerable suffocating odour, when the gas is burnt which is particularly perceptible in low rooms illuminated with such gas.

[19]It is chiefly a mixture of carbonic oxid, and hydrogen gas.

These observations also apply to the distillation of tar, which when distilled either in a vaporous or nascent state, during its first production from coal in the ordinary process, or if it be submitted to a second distillation, mingled with a fresh portion of pit-coal, a practice usually had recourse to when this product cannot be disposed of more advantageously. The best depth of coal in the retort for procuring excellent gas, and at the same time for yielding the greatest quantity from the same weight in the shortest possible time, is about six inches.

The brightness of the coal-gas flame is rather diminished when the gas has been long kept over water, and hence for illumination it should be used as soon as prepared, but of course properly purified.

The quantity of gas taken up by water is affected by temperature, because the temperature increases its elasticity; the quantity of gas absorbed, diminishes as the temperature increases, and increases as the temperature diminishes.1⁄27part of its own bulk of pure coal-gasis absorbed by the water over which it is confined in the gazometer.

The chemical constitution of this gazeous fluid is best ascertained by burning it in a vessel of oxygen gas, over lime-water in a pneumatic reservoir, by means of a bladder and bent brass pipe. Two products are then obtained, viz. water and carbonic acid. That water is produced, may be shown by burning a very small stream of the gas in a long funnel-shaped tube open at both ends. The formation of carbonic acid is evinced, by the copious precipitation of the lime-water in the foregoing experiment.

If carburetted hydrogen be mixed with a sufficient quantity of oxygen gas or common air and fired by the electric spark, or by any other method, an explosion takes place more or less violent according to the quantity of carbonaceous matter condensed in the hydrocarbonat; and the remaining gas consists of carbonic acid, together with any unconsumed gas, or excess of oxygen, whilst the water condenses in drops on the sides of the vessel. A few cubic inches of the mixed airs is as much as can be conveniently managed at a single explosion; and when any portion ofolefiant gas is present, even this quantity will endanger very thick glass jars. A very vivid red flame appears at the moment of the explosion, and a great enlargement takes place in an instant, after which the bulk is suddenly reduced to much less than the original quantity. When the carbonic acid is absorbed by lime-water, if the gasses have been properly proportioned, no gazeous residue is left, except accidental impurities. Though carburetted hydrogen gas, is sometimes naturally produced in coal-mines, and occasionally mixes with common air, producing dreadful explosions, yet when coal-gas is mixed with common air, it does not explode unless the gas be to the air as 1 to 10 nearly. Such are the leading chemical habitudes of this gazeous product. The varieties of carburetted hydrogen gas all agree in being inflammable; but they possess this property in various degrees, as is evinced by the variable brightness of the flame which they yield when set on fire.

“Messrs.SobolewskyandHorrer, of St. Petersburgh, have employed wood for the purpose of producing carburetted hydrogen gas. The pyroligneous acid obtained in this operation, when freed from the empyreumatic oil withwhich it is mixed, becomes acetous acid, and is applicable to all the uses of vinegar. A cubic cord of wood equal to 2.133 French metres (a metre being rather more than an English yard), yields 255 Paris pounds of charcoal, and 70 buckets of acid. The latter gives 30 pounds of tar, after the extraction of it 50 buckets of good vinegar remain. The same quantity of wood furnishes 50,000 cubic feet of gas, sufficient for the supply of 4000 lamps for five hours.”[20]

[20]See Repository of Arts, Vol. XI. No. 36, p. 341.

From what has been stated in the preceding pages it becomes obvious, that a substance yielding an artificial light may be obtained from common coal in immense quantities. The attempt to derive advantage from so valuable a discovery is surely no idle speculation. Let us therefore now consider to what objects of public and private utility this mode of procuringlight may be applied with effect. It is obvious that coal-gas may be preserved in a reservoir for any length of time and that it may be conveyed by means of tubes to any distance flowing equably and regularly like water. Those, indeed, who have not seen the contrivance will find it difficult to imagine with what ease it is managed. The gas may be distributed through an infinity of ramifications of tubes with the utmost facility. Near the termination of each of the tubes through which it flows, it is confined by a valve or stop-cock, upon turning which, when required to be lighted, it flows out in an equable stream and ascends by its specific levity. There is nothing to indicate its presence; no noise at the opening of the stop-cock or valve—no disturbance in the transparency of the atmosphere—it instantly bursts on the approach of a lighted taper, into a brilliant, noiseless, steady and beautiful flame. Its purity is attested by its not blacking or soiling in the least degree the metallic orifice from which it issues, nor even a sheet of white paper, or polished surface brought in contact with it. There is no escape of combustible matter unconsumed, which is so great a nuisancein all our common lights. The products of the combustion are water and carbonic acid gas[21]. The accurate and elegant experiments of Dr. W.Henryhave shewn in the most satisfactory manner, that considerably less carbonic acid is produced by the flame of coal-gas, than by that of oil, tallow, or wax[22], whichsufficiently refutes the absurd notions that have been circulated respecting the pernicious effects of gas-lights. But if the gas from Newcastle coal is badly prepared, or not deprived of the portion of sulphuretted hydrogen, which it usually contains, it then emits fiery sparks and produces a portion of sulphureous acid by virtue of the union of the oxygen of the air with the sulphur dissolved in the gas, the consequence of which is, a suffocating odour, which is particularly observable in the higher stratum of the air of apartments in which the gas is burnt. Such gas likewise tarnishes all metallic bodies—it discolours the paintings effected with metallic oxids, and always produces a suffocating odour very noxious to health. It is freed from the sulphuretted hydrogen and may be rendered fit for illumination by passing it repeatedly through very dilute solutions of sub-acetate of lead, green sulphate of iron, quicklime and water, or hyper-oxymuriate of lime.

[21]The water (which passes off in imperceptible vapour) is generated by part of the oxygen of the air uniting with part of the hydrogen, which forms the great bulk of the coal-gas: and the carbonic acid gas is produced by the union of another portion of the oxygen uniting with the smaller portion of carbon, which is the other component part of the coal-gas.

[22]100 Cubic inches of carburetted hydrogen from coal, require for burning 220 cubic inches of oxygen and produce 100 cubic inches of carbonic acid—100 cubic inches of the same gas obtained from wax, require for burning 280 cubic inches of oxygen and produce 137 cubic inches of carbonic acid—100 cubic inches of the same gas procured from lamp-oil, require 190 cubic inches of oxygen for burning, and produce 124 cubic inches of carbonic acid.The following lines relating to the salubrity of the gas-light illumination are copied from Mr. Lee’s evidence in the House of Commons, when examined on that subject.Question—“Is the health of your manufacturers at all affected by the use of gas?—Answer—Not in the least, or I would not have adopted it. I believe I explained to the Committee, that I used the gas-lights in my own house first.”Q. “You have not seen the smallest alteration in the health of your workmen?—A. Not in the least, for had I seen it, it would have been a fatal objection to it.”Q. “And you say the same in regard to the use of the gas-lights in your own family?—A. Certainly I do.”

The following lines relating to the salubrity of the gas-light illumination are copied from Mr. Lee’s evidence in the House of Commons, when examined on that subject.Question—“Is the health of your manufacturers at all affected by the use of gas?—Answer—Not in the least, or I would not have adopted it. I believe I explained to the Committee, that I used the gas-lights in my own house first.”Q. “You have not seen the smallest alteration in the health of your workmen?—A. Not in the least, for had I seen it, it would have been a fatal objection to it.”Q. “And you say the same in regard to the use of the gas-lights in your own family?—A. Certainly I do.”

The following lines relating to the salubrity of the gas-light illumination are copied from Mr. Lee’s evidence in the House of Commons, when examined on that subject.

Question—“Is the health of your manufacturers at all affected by the use of gas?—Answer—Not in the least, or I would not have adopted it. I believe I explained to the Committee, that I used the gas-lights in my own house first.”

Q. “You have not seen the smallest alteration in the health of your workmen?—A. Not in the least, for had I seen it, it would have been a fatal objection to it.”

Q. “And you say the same in regard to the use of the gas-lights in your own family?—A. Certainly I do.”

As to the brilliancy of the flame, an appeal may be made to every one who has witnessed the gas-light illumination, whether it be not superior to the best wax candle-light, or the light of Argand’s lamps.

It may be described as a rich compact flame, burning with a white and agreeable light. It is also perfectly steady, when the flame is limited to a moderate size: in large masses, it is subject to that undulation which is common to it with all flames of certain dimensions, and is caused by the agitation of the surrounding atmosphere. The gas flame is entirely free from smell. The coal-gas itself certainly has a disagreeable foetid odour before it is burnt, so has the vapour of wax, oil, and tallow, as it comes from a lamp or candle newly blown out. This concession proves nothing against the flame of gas which is perfectly inodorous, a white handkerchief, passed repeatedly through it and applied to the nose, excites no odour.

Another peculiar advantage of the gas flame is, that it may be applied in any direction we please, as there is nothing to spill and the gas is propelled by a certain force which is always the same, it will burn equally well in an almost horizontal as in an upright position; and we can thus obviate two great objections to all our artificial lights, that their least luminous end is directed downwards where the light is generally most wanted, and that a shade is cast belowby the stand or support of the combustible matter.

The size, shape and intensity of the gas-flame may be regulated by simply turning a stop-cock which supplies the gas to the burner. It may at command be made to burn with an intensity sufficient to illuminate every corner of a room, or so low and dim as barely to be perceived. It is unnecessary to point out how valuable such lights may be in nurseries, stables, warehouses, in the chambers of the sick, &c.

From the facility with which the gas-flame can be conveyed in any direction, from the diversified application, size and shape which the flame can be made to assume, there is no other kind of light so well calculated for being made the subject of splendid illuminations.

Where lustres are required in the middle of a room, the best mode of conducting the gas to the chandelier, is to pass the gas-pipe through the ceiling from the room above, immediately over the lustre. This can be easily done without injury to the apartment.

Where side-lights and chandeliers are required the tubes need never appear in sight, but may be concealed in the wall or floor of thehouse. When transparencies are wanted as decorations for halls, lobbies, &c. more than light, recesses may be filled with different colouredmedia, or paintings, and any intensity of light may be thrown on the object.

If a number of minute holes are made in the end of a gas pipe, it forms as manyjets de feu, which have a very brilliant appearance; these may sometimes be placed in the focus of a parabolic reflector. In cases where the light is required to be thrown to a distance, other burners are constructed upon the same principle as the Argand lamp, forming a cylinder of flame, and admitting a current of air both to the inside and outside.

On comparing the flame of a gas-light with the flame of a candle whatever its size may be, it appears just as yellow and dull as the flame of a common lamp appears when compared with that of a lamp of Argand. The beautiful whiteness of gas-light never fails to excite the surprize and admiration of those who behold it for the first time.

A large edifice or manufactory lighted by gas, contrasted with one of the same kind lighted by candles or lamps, resembles a street on thenight of a general illumination, compared with the glimmering light of its ordinary parish lamps.

The intensity of one of the parish gas-light lamps, now exhibited in the streets of this metropolis, will bear ample testimony of this assertion; the light of the parish gas-lamps, is to the intensity of the parish oil lamps as 1 to 12.

One of the most obvious applications of the gas-light illumination unquestionably consists in lighting streets, shops and houses; and let it be observed that as this is found safe and economical, it proves all that the most ardent friends of the gas-light system can desire. For in contending with the common mode of lighting the streets and shops, the new lights must beat out of the market the cheapest of all artificial lights; and as it has succeeded in doing this it shews in the most satisfactory point of view, the prodigious advantages of gas-lights when compared with the materials of tallow and oil.

The original expence of laying the pipes for conveying the gas, together with the cost of the machinery, is all that is required; the preparation of the gas being itself a lucrative process,no doubt will pay all its expences besides the interest of capital, and leave a surplus of profit.

Indeed the application of the coal-gas, as a substitute for tallow and oil, to illuminate houses, shops, &c. is no longer problematical, a considerable extent of this capital, together with numerous shops and houses being already supplied with this species of light.[23]

[23]The Liberty of Norton Falgate, as far as Bishopgate-street, is lighted with gas-light, from the Chartered Company’s station at Norton Falgate; and gas-light pipes are laid from that station as far as the west end of Cheapside, and in all the streets north of that great thoroughfare.In the West end of the Town, the main pipes for supplying the streets and houses with light from the Gas-Light Company, extend through the most eligible parts; from their Establishment in Peter-street, Westminster, along the line from Pall Mall to Temple-bar, compleatly surrounding the parish of St. Martin’s in the Field. Main pipes are also placed in the Hay-market, Coventry-street, Long-Acre, St. Martin’s-lane; and in the principal parts of the parishes of St. James and St. Ann.In the East end of the metropolis, the gas-lightmainsextend from Cornhill to St. Paul’s, Wood-street, Fore-street, &c.—Consent has also been given to the incorporated Gas-Light Company for laying their pipes in the parish of St. Stephen’s in the Field; St. Paul Covent-garden; St. Mary-le-Strand; St. Clement Danes; St. George’s, Bloomsbury; St. Giles’s in the Fields; St. Andrew’s, Holborn, above the bars; part of the parish of St. Mary-la-bonne; besides several other districts, comprehending the whole of the city and suburbs of Westminster.

In the West end of the Town, the main pipes for supplying the streets and houses with light from the Gas-Light Company, extend through the most eligible parts; from their Establishment in Peter-street, Westminster, along the line from Pall Mall to Temple-bar, compleatly surrounding the parish of St. Martin’s in the Field. Main pipes are also placed in the Hay-market, Coventry-street, Long-Acre, St. Martin’s-lane; and in the principal parts of the parishes of St. James and St. Ann.

In the East end of the metropolis, the gas-lightmainsextend from Cornhill to St. Paul’s, Wood-street, Fore-street, &c.—Consent has also been given to the incorporated Gas-Light Company for laying their pipes in the parish of St. Stephen’s in the Field; St. Paul Covent-garden; St. Mary-le-Strand; St. Clement Danes; St. George’s, Bloomsbury; St. Giles’s in the Fields; St. Andrew’s, Holborn, above the bars; part of the parish of St. Mary-la-bonne; besides several other districts, comprehending the whole of the city and suburbs of Westminster.

Enough therefore, has been done to prove the possibility of lighting houses, and streets, withgas, which would have been regarded twenty years ago as an extravagant paradox.[24]

[24]I am informed by Mr.Clegg, the engineer of the Chartered Gas-Light Company, under whose direction the new system of lighting is carried on, that the total length of pipe laid down, as mains, in the streets of London amounts already to nearly 15 miles.In the Eastern part of London, the same Company is engaged to lay their pipes in the principal parts of Whitechapel, Spitalfields, St. Luke’s, and the adjoining neighbourhood.One part of the city of London, extending from Temple-bar to the West end of Cheapside; from Newgate-street to Holborn Bars, together with the intervening streets, is also provided with pipes laid down by another gas-light association, who have opened a new Establishment in Water-lane, Fleet-street, but are unconnected with the Chartered Company. A third company is projected in Southwark, and a fourth in the Eastern district of London, creating by a rivalry of interest, that laudable competition which always proves beneficial to the public at large, and which cannot fail to accelerate the progress of this new art of procuring light.

In the Eastern part of London, the same Company is engaged to lay their pipes in the principal parts of Whitechapel, Spitalfields, St. Luke’s, and the adjoining neighbourhood.One part of the city of London, extending from Temple-bar to the West end of Cheapside; from Newgate-street to Holborn Bars, together with the intervening streets, is also provided with pipes laid down by another gas-light association, who have opened a new Establishment in Water-lane, Fleet-street, but are unconnected with the Chartered Company. A third company is projected in Southwark, and a fourth in the Eastern district of London, creating by a rivalry of interest, that laudable competition which always proves beneficial to the public at large, and which cannot fail to accelerate the progress of this new art of procuring light.

In the Eastern part of London, the same Company is engaged to lay their pipes in the principal parts of Whitechapel, Spitalfields, St. Luke’s, and the adjoining neighbourhood.

One part of the city of London, extending from Temple-bar to the West end of Cheapside; from Newgate-street to Holborn Bars, together with the intervening streets, is also provided with pipes laid down by another gas-light association, who have opened a new Establishment in Water-lane, Fleet-street, but are unconnected with the Chartered Company. A third company is projected in Southwark, and a fourth in the Eastern district of London, creating by a rivalry of interest, that laudable competition which always proves beneficial to the public at large, and which cannot fail to accelerate the progress of this new art of procuring light.

The Church of St. John the Evangelist in this metropolis has been illuminated with gas-lights for upwards of two years: the lights employed in this edifice is equal to 360 tallow candles eight to the pound. The avenues to the House of Lords and House of Commons, Westminster-hall, Westminster-bridge; the house and offices of the Speaker of the House of Commons, the Mansion-house, and many other places, deserve to be named, as having already adopted this species of illumination.

Another advantageous application of the gas-light must be the supplying of light-houses.

From the splendour and distinguishing forms which the gas-light flame is capable of assuming, no light is better calculated for signal-lights than this. By means of one single furnace as much gas might readily be procured as would furnish a flame of sufficient intensity, during the longest winter night, exceeding in brilliancy or intensity of light any light-house in Britain or elsewhere.

If every light-house round this island were possessed of a gas-light furnace, one-half part of the enormous expence which they at present require would furnish a much more brilliant light. The cheapness of this light and its efficacy for the purpose, would soon multiply the number of light-houses, and thus most essentially contribute to the security of navigation on our coast. The gas may be made to issue from tubes by long narrow slips, and a surface of flame produced of any given dimensions, and free from all smoke that would obscure the reflectors.

The ease with which the largest gas-light flame is instantly extinguished by shutting thestop-cock, and the readiness with which a long line of gas catches fire by applying a lighted taper to one extremity, are properties that cannot fail to recommend it for the purposes of telegraphic communications by night. Another application of the gas unquestionably might be the lighting of barracks, arsenals, dock-yards, and other establishments where much light is wanted in a small place.

The annual expence of lighting the barracks of Great Britain is said to fall little short of 50,000l. a small part of which on the new plan, would supply them with a much purer and safer light.

The uses of the gas-lights already enumerated must of themselves, justify us in attaching great importance to the discovery, and if reduced to practice all over the kingdom, would employ a large capital in a way the most advantageous and productive. But the utility of this light will be almost indefinitely increased to the use of private families. That such an application is practicable, in all towns of Great Britain, is obvious, from what has been done already, and that it would be highly economical and ornamental, there can be little doubt.

By means of gas we may have a pure and agreeable light at command in every room of our house, just as we have the command of water, with this singular advantage, that these lights may burn for hours within an inch of the most combustible substance without danger, because they neither can burn down like a candle nor emit sparks. These properties make the gas-lights a most desirable light on board our ships of war, where severe regulations are necessary to prevent danger from fire, which after all are frequently evaded. The gas-light might be used in the store-rooms, and even in the powder magazine, and the captain would completely command the supply of light by the possession of the key which opens and shuts the stop-cock. A small apparatus which may be erected at a trifling expence would be sufficient for that purpose.

In shops, counting-houses, and public offices, the advantages are a white light, nearly equal to day-light, a warmth which almost supersedes the use of fires, a total absence of smoke, smell, and vapour, and great economy of labour.

The heat produced by gas-lights must be observed by every one who has had an opportunityof attending to it in the most superficial manner, and the reason why gas-lights produce more heat than oil or candle-light will not appear strange to our chemical readers (and who is there now that does not know something of chemistry?) when it is considered that the gas-light flame condenses more air than the flame of oil and tallow, and consequently must produce more heat.

The flame of gas may be produced in so large a surface, as to be applied to heat the most spacious apartments as well as to light them.

If the gas is made to issue by a circular rim of about twelve inches diameter; it forms a sort of an Argand lamp on a great scale, and it is manifest that a circumference of three feet of flame will heat the air very rapidly, and with such uniformity that we need no longer be exposed to the partial heating occasioned by the strong draft of a large fire. A lamp of this description in the centre of a large room, with a very small fire to secure a gradual renewal of the air would enable us to enjoy the most healthful and agreeable temperature.

From trials made on this subject, I am enabledto state, that three Argand’s lamps, consuming five cubic feet of gas per hour, are sufficient to keep a room 10 feet square at a temperature of 55° Fahr. when the air without doors has a temperature of freezing.[25]

[25]Mr.Dalton’s method of ascertaining the comparative quantity or effects of heat evolved during the combustion of different inflammable gases, and other substances capable of burning with flame, as stated in his System of Chemistry, vol. I. p. 76, deserves to be recommended to those who are more immediately interested in this subject. The process, which is simple, easy, and accurate, is as follows:Take a bladder of any size, (let us suppose for the sake of illustration, the bladder to hold or to be equal in capacity to 30,000 grains of water,) and having furnished it with a stop-cock and a small jet pipe, fill it with the combustible gas the heating power of which is to be tried. Take also a tinned iron vessel with a concave bottom of the same capacity, pour into it as much water as will make the vessel and water together equal to the above stated bulk of water in the bladder, viz. 30,000 grains. This being done, set fire to the gas at the orifice of the pipe, and bring the point of the flame under the bottom of the tinned vessel, and suffer it to burn there, by squeezing the bladder till the whole of the gas is consumed. The increase of temperature of the water in the tinned vessel being carefully noticed before and after the experiment, gives very accurately the heating power of the given bulk of the inflammable gas.It was thus proved that—Olefiant gas raises an equal volume of water14°Carburetted hidrogen, or coal gas10Carbonic oxid4Hidrogen5Spermaceti oil 10 grains burnt in a lamp raised 30,000 grains of water5Tallow5Wax5,75Oil of turpentine3Spirit of wine2

Take a bladder of any size, (let us suppose for the sake of illustration, the bladder to hold or to be equal in capacity to 30,000 grains of water,) and having furnished it with a stop-cock and a small jet pipe, fill it with the combustible gas the heating power of which is to be tried. Take also a tinned iron vessel with a concave bottom of the same capacity, pour into it as much water as will make the vessel and water together equal to the above stated bulk of water in the bladder, viz. 30,000 grains. This being done, set fire to the gas at the orifice of the pipe, and bring the point of the flame under the bottom of the tinned vessel, and suffer it to burn there, by squeezing the bladder till the whole of the gas is consumed. The increase of temperature of the water in the tinned vessel being carefully noticed before and after the experiment, gives very accurately the heating power of the given bulk of the inflammable gas.

It was thus proved that—

In all processes of the arts where a moderate heat is wanted the gas-light flame will be found very advantageous—even on a large scale this flame may be used with profit. It possesses advantages which cannot be obtained from flaming fuel, where much nicety is required; because no fuel can be managed like the flame of coal-gas. For it is well known, that when toolittle air be given to flaming fuel it produces no flame, but sooty vapour; and if too much air be admitted to make those vapours break out into flame, the heat is often too violent. It is a fact, that flame, when produced in great quantity, and made to burn violently, by mixing with a proper portion of fresh air, driving it on the subject, and throwing it into whirls and eddies, thereby mixing the air with every part of the hot vapour, produces a very intense heat.

The great power of a gas-flame does not appear when we try small quantities of it, andallow it to burn quietly, because the air is not intimately brought into contact with it, but acts only on the outside; and the quantity of burning matter in the surface of a small flame is too minute to produce much effect.

Gas lampsLarger image(252 kB)

Larger image(252 kB)

But when the flame is produced in large quantity and is freely brought forward into contact and agitated with air, its power to heat bodies is immensely increased. It is therefore peculiarly proper for heating large quantities of matter to a violent degree, especially if the contact of solid fuel with such matter is inconvenient.

As the gas-flame may be made to assume any shape and intensity, and as there is nothing to spill, it may be exhibited under such variety of forms and designs, as cannot fail to give rise to the most tasteful ornamental illumination.

PlatesIII.IV.andV.exhibit such designs of different kinds of gas-lamps, chandeliers, lustres, candelabras, &c. as are already in use in this Metropolis.

PlateIII. fig. 1, represents aRod Lamp. The gas passes through the roda, to the Argand burner, which is surrounded by a cylindrical chimney,c, swelling out at the lowerextremity. The construction of the Argand burner we have mentioned already,p.78.

In all the gas-light burners, constructed on Argand’s plan, care should be taken that the flame be in contact with the air on all sides, and that the current of air be directed towards the upper extremity of the flame. This may be effected by causing a current of air to rise up perpendicular from the bottom of the chimney glass, and to pass out again through the contracted part, or upper extremity of the chimney; but no other current of air should ever be permitted to come near the gas-flame, or enter the glass chimney which covers or defends the light; for if more air be permitted to mix with the flame than is sufficient for the compleat combustion of the coal-gas, it necessarily diminishes the heat, and consequently reduces the quantity of light.

Fig. 2.A Rod Gas Lamp, with branches.The gas passes through the hollow rod,a, and part of the hollow branch,b, to the burner of the lamp. The cylindrical shaped glass,c, exhibited in this figure, is not so well adapted for the compleat combustion of coal-gas, as the belly-shaped chimney,c, represented infig. 1, 3, 5, 6, because the ascending current of fresh air is not turned out of its perpendicular course, and thrown immediately in a concentrated state, into the upper part of the flame where the combustion of the gas is less perfect. The exterior current of air which enters at the bottom into the lamp, rises merely with a velocity proportioned to the length of the cylinder, and to the rarefaction of the air in the same, but without being propelled to the apex of the flame, as it should do, and is made to do, in the bellied glass adapted to the lamp,fig. 1.

Fig. 3.A Bracket Lamp.a, the tube which conveys the gas to the burner;b, the stop-cock of the tube.

Fig. 4.A Pendent Rod Lamp; in which the gas is supposed to come from a pipe above, through the ceiling, into the pipe,a, to supply the burners. The tulip-shaped chimney,b, of this lamp, is likewise ill adapted for gas-light burners.

Fig. 5.A pendent double-bracket Lamp.The gas passing through the perpendicular tube,a, into the brackets,bb;cshows the Argand burner.

Fig. 6.A swing Bracket Lamp.a, the gas-pipe with its stop-cock;b, a brass ball, communicating with the pipe,a;c, the conducting tube, ground air-tight into the ball,b, and communicating with the burner of the lamp, so as to allow it to have an horizontal motion.

Fig. 7. Shews the construction of the ballb, and pipe,c, of the lamp,fig. 6.

Fig. 8.A Swing Cockspur Lamp, constructed upon the same plan asfig. 6. These two lamps are very convenient for desks in counting-houses, &c.

Fig. 9. A stop-cock with ball and socket, which, when adapted to a gas-light pipe, allows it to have an universal motion, so that the light may be turned in any direction.

Fig. 10. Section of the stop-cock, with ball and socket.

Fig. 11. Shows the ball and socket,fig. 9, in perspective.

Gas lampsLarger image(205 kB)

Larger image(205 kB)

PlateIV,[26]fig. 1.A Candelabrum; the gaspipe ascending from the floor of the apartment, through the columna, and terminating in the burner of the lamp.

[26]The gas-lamps exhibited in this plate, are employed in the library, counting-house, warehouse, and offices of Mr.Ackerman, and, by whose permission, they are copied on this occasion.

Fig. 2.A fancy pendent Cockspur Lamp.The gas being transmitted to the burners,cc, by means of the pipe,a.

Fig. 3.A Pedestal Argand Lamp.a, the pipe and stop-cock, which transmits to, and shuts off the gas from the burner of the lamp.

Fig. 4.A Pedestal Cockspur Lamp.a, the stop-cock and gas-pipe.

Fig. 5.A fancy bracket Cockspur Lamp, intended merely to show that the coal-gas, as it passes to the burner, is perfectly devoid of colour, and invisible.ais a glass vessel furnished at its orifice with a brass cap,c, and perforated ball, out of which the gas-flame proceeds.b, the pipe which conveys the gas into the glass vessel,a.

Fig. 6.A Bracket Argand Lamp.aandb, the gas pipe communicating with the burner.

Fig. 7 and 8.A Horizontal Bracket Lamp.a, the gas pipe, supposed to be concealed in the ceiling.b, the communicating pipe, which, together withc, branches out at right angles atdd.ee, are the burners of the lamp.

Gas lampsLarger image(286 kB)

Larger image(286 kB)

PlateV.fig. 1.A Candelabrum, into which the gas-pipe ascends from the floor of the apartment, the lateral branches communicating with the central tube.

Fig. 2.An Arabesque Chandelier.The gas enters from the ceiling of the room into the rope-shaped pipe,a, from which it proceeds through one of the arched ribs,bb, into the horizontal hoop, or pipe,c.

Fig. 3.A Roman Chandelier.The gas enters through the inflexible hollow chain,a, into the central tube,b, from whence the burners are supplied by the lateral branches,cc.

Fig. 4.A Gothic Chandelier.The gas is transmitted to the burners through the rope,a, which includes a tube, and the communication with the burners is established through the lateral branches.

Fig. 5.A Pedestal Figure Lamp.The gas is here made to pass by means of a pipe through the body of the figure into the lattice-workplateau, constructed of hollow and perforated brass tubes.

Fig. 6.A Pedestal Vase Lamp.The gas-tube enters through one of the claw-feet of the altar-shaped pedestal, into the glass vase,a, atthe bottom of which it joins the tubes communicating with the metallic corn-ears,b, at the upper extremities of which it formsjets de feu.

Fig. 7.A Girandole.The gas enters through the bracket,a, and is conveyed to the burners by the descending tubes,bb.

Fig. 8.A Candelabrum, having a central pipe, through which the gas is conducted to the burner at the top.

Having thus far considered the nature of coal-gas as a substitute for the lights now in use, it will be necessary to attend more particularly to some other products which are obtained during the production of this species of light: namely, coke, tar, ammoniacal liquor, &c.

Coke.—The substance called coke, which constitutes the skeleton of the coal, or its carbonaceous base, is left behind in the retort, afterall the evaporable products have been expelled from the coal by heat.—Seepage 85.

It is sufficiently known, that coke is a more valuable fuel than the coal from which it is obtained.

Hence, immense quantities are prepared in the large way, but the gazeous and other substances are lost in the process employed for carbonizing the coal.[27]In the manufactureof coal-gas, the coke comes from the retort, enlarged in size, and greatly diminished in weight, when compared with the original coal. In whatever state the coal may be when introduced into the retort, the coke is uniformly taken out in large masses, so that the refuse coal, or dust, and sweepings of the pit, which are now thrown away, may be employed and converted into an excellent fuel. Coke is decidedly superior to coal for all domestic, and more especially for culinary purposes; the heat which it throws out being more uniform, more intense, and more durable. No flame, indeed, accompanies it, and it seldom needs the application of the poker,—that specific for theennuiof Englishmen; but these deficiences are more than balanced by the valuable property of emitting no sparks, of giving more heat, and burning free from dust and smoke.

Back to Index Next