Gas light

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 ditto, with wooden framing 160 11
Wrought iron cistern for gasometer—36 feet wide, 24 feet long and 16 feet deep 500 0
(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 for ditto, compleat 336 0
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.

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.

Theory of the Combustion of Coal in Elucidation of the Nature and Production of Gas Light

Pit-coal exists in this island in strata, which, as far as concerns many hundred generations after us, may be pronounced inexhaustible; and is so admirably adapted, both for domestic purposes and the uses of the arts, that it is justly regarded as a most essential constituent of our national wealth. Like all other bituminous substances, it is composed of a fixed carbonaceous base or bitumen, united to more or less earthy and saline matter constituting the ashes left behind when this substance is burnt. The proportions of these parts differ considerably, in different kinds of coal; and according to the prevalency of one or other of them, so the coal is more or less combustible, and possesses the characters of perfect pit-coal; and by various shades, passes from the most inflammable canel-coal, into blind, Kilkenny, or stone-coal; and, lastly, into a variety of earthy or stony substances; which, although they are inflammable, do not merit the appellation of coal.

Every body knows that when pit-coals are burning in our grates, a flame more or less luminous issues from them, and that they frequently emit beautiful streams of flame remarkably bright. But besides the flame, which is a peculiar gas in the state of combustion, heat expels from coal an aqueous vapour, loaded with several kinds of ammoniacal salts, a thick viscid fluid resembling tar, and some gases that are not of a combustible nature. The consequence of which is, that the flame of a coal-fire is continually wavering and changing, both in shape, as well as brilliance and in colour, so that what one moment gave a beautiful bright light, in the next, perhaps, is obscured by a stream of thick smoke.

But if coals, instead of being suffered to burn in this way, are submitted to distillation in close vessels, all its immediate constituent parts may be collected. The bituminous part is melted out in the form of tar. There is disengaged at the same time, a large quantity of an aqueous fluid, contaminated with a portion of oil, and various ammoniacal salts. A large quantity of carburetted hidrogen, and other uninflammable gases, make their appearance, and the fixed base of the coal remains behind in the distillatory apparatus in the form of a carbonaceous substance, called coke.

All these products may be separately collected in different vessels. The carburetted hidrogen, or coal-gas, may be freed from the non-inflammable gases, and afterwards forced in streams out of small appertures, which, when lighted, may serve as the flame of a candle to illuminate a room or any other place. It is thus, that from pit-coal a native production of this country, we may procure a pure, lasting, and copious light; which, in other cases, must be derived from expensive materials, in part imported from abroad.

It is chiefly upon the power of collecting the products afforded by coal, with convenience and cheapness, that the promoters of the gas-light illumination found their claims to public encouragement. They conceive that the flame which pit-coal yields, as it is now consumed, is turned to very little advantage: it is not only confined to one place, where a red heat is more wanted than a brilliant flame, but it is obscured, and sometimes entirely smothered, by the quantity of incombustible materials that ascend along with it and pollute the atmosphere.

That much inflammable matter is thus lost, is evident from facts that come under our daily observation. We often see a flame suddenly burst from the densest smoke, and as suddenly disappear; and if a light be applied to the little jets that issue from the bituminous parts of the coal, they will catch fire, and burn with a bright flame. A considerable quantity of a gazeous fluid, capable of affording light and heat continually escapes up the chimney, whilst another part is occasionally ignited, and exhibits the phenomena of the flame and light of the fire.

The theory of the production of gas-light is therefore analogous to the action of a lamp or candle. The wick of a candle being surrounded by the flame, is in the same situation of the pit-coal exposed to distillation. The office of the wick is chiefly to convey tallow, by capillary attraction, to the place of combustion. As it is decomposed into carburetted hidrogen gas it is consumed and flies off, another portion succeeds; and in this way a continued current of tallow and maintenance of flame are effected. See page 15 .

The combustion of oil by means of a lamp depends on similar circumstances. The tubes formed by the wick serve the same office as a retort placed in a heated furnace through which the inflammable liquid is transmitted. The oil is drawn up into these ignited tubes, and is decomposed into carburetted hidrogen gas, and from the combustion of this gas the illumination proceeds. What then does the gas-light system attempt? Nothing more than to generate, by means of sufficient furnaces and a reservoir of sufficient capacity, desired quantities of the gas, which is the same material of the flame of candles or lamps; and then by passing it through pipes to any desired distance, to exhibit it there at the mouths of the conducting tubes, so that it may be ignited for any desired purpose. The only difference between this process and that of an ordinary candle or lamp, consists in having the furnace at the manufactory, instead of its being in the wick of the candle or lamp—in having the inflammable material distilled at the station, instead of its present exhibitions in oil, wax, or tallow, and then in transmitting the gas to any required distance, and igniting it at the orifice of the conducting pipe instead of igniting it at the apex of the wick. The principle is rational, and justified by the universal mode in which all light is produced. Indeed, this discovery ranks among the numerous recent applications of chemical science to the purposes of life, which promise to be of the most general utility.

It is evident from the outline here given of the production and application of coal-gas, that all the uses of pit-coal are not exhausted; it will be sufficient to observe, that the complete analysis of coal, which has been hitherto confined to the laboratory of the chemist, requiring skill and nicety in the operator, and attended with great trouble and expence, is now so far simplified, that many chaldrons of coals may be decomposed by one gas-light apparatus in the space of six hours, and all the component parts produced in their most useful shape, at an expence out of all proportion below the value of the products.

Theory of the Production of Gas-Light, and Description of A Portable Apparatus for Exhibiting, in the Small Way, the General Nature of This Species of Light

To obtain carburetted hidrogen, or coal-gas, from common pit-coal, and to apply it for the purposes of illumination, the coal is introduced into large iron cylinders, called retorts, to the apertures of which iron pipes are adapted, terminating in a vessel, or vessels, destined to purify and collect the gas. The retorts charged with coals and made air-tight, are placed upon the fire, the action of which extricates the gazeous products from the coals, together with an aqueous ammoniacal vapour, and a tenaceous bituminous fluid, or tar, &c. The liquid substances are conveyed into proper vessels, and the gazeous products are conducted, by means of pipes, under the gasometer, where the gas is again washed, and remains ready for use. There are also other pipes leading from the gasometer, which branch out into smaller ramifications, until they terminate at the places where the lights are wanted. The extremities of the pipes have small apertures, out of which the gas issues, and the streams of gas being lighted at those apertures burn with a clear and steady flame as long as the supply of gas continues. All the pipes which come from the gasometer are furnished at their extremities with stop-cocks to regulate the admission of the gas. The burners are formed in various ways, either a tube ending with a simple orifice, at which the gas issues in a stream, and if once lighted will continue to burn with the most steady and regular light imaginable, as long as the gas is supplied; or two concentric tubes of brass, or sheet-iron, are placed at a distance of a small fraction of an inch from each other, and closed at the bottom. The gas which enters between these cylinders, when lighted, forms an Argand lamp, which is supplied by an internal and external current of air in the usual manner. Or the two concentric tubes are closed at the top with a ring having small perforations, out of which the gas alone can issue, thus forming small distinct streams of light.

Gas-apparatus

Larger image  (279 kB)

The gas-apparatus, plate 2 , will be found very convenient for exhibiting, in the small way, the general nature of this new art of illumination, whilst at the same time it may serve to ascertain, at a trifling expence, the comparative value of different kinds of coals intended to be employed for the production of this species of light, as well as other occasional purposes connected with the gas-light system of illumination.

It consists of three distinct apparatus:—namely, a portable furnace, fig. 1, plate 2 , by means of which the gas is prepared—fig. 2 , a purifyer, or condenser, which separates and purifies the products obtained from the coal, so as to render the gas fit for the purpose of illumination—fig. 3 , a gasometer, or reservoir for receiving and preserving the purified stock of gas, and from which it may be transferred and distributed as occasion may require. The following statement will explain more fully the general nature of this portable chamber apparatus:—a, represents a cast iron retort, such as is used for chemical operations in the small way. This retort rests upon a tripod of hammered iron, placed upon the bars of the grate of the chemical furnace. Into this retort the coals are put for furnishing the gas. It is provided with a solid iron stopper ground air-tight into the mouth of the retort, and the stopper is secured in its place by an iron wedge passing over it in the centre; by means of which the mouth of the retort when charged with coal is readily made air-tight, and the stopper may easily be removed by knocking out the iron wedge. b. is a metal pipe which conveys all the distillatory products from the retort into the purifier fig. 2 . This tube is bent at right angles at the extremity where it enters the intermediate vessel fig. 2 . The purifier fig. 2 , is divided into three compartments marked c. d. e. The first compartment is filled with water, and by means of it an air-tight communication is established with the retort which furnishes the gas. The second compartment, d, contains a solution of caustic pot-ash composed of about 2 parts of caustic pot-ash and 16 of water, or a mixture of quick-lime and water of the consistence of very thin cream. The object of this compartment is to separate the non-inflammable gases and other products evolved during the distillation of the coal, from the carburetted hidrogen or coal-gas, so as to render it fit for use. The third compartment e  is left empty to receive the tar and other liquid products. Into the first compartment c, all the gazeous and liquid products are delivered, as they become evolved during the distillation, by means of the pipe b. The compartment d, of the purifier, or alcali vessel, is furnished with a wide perpendicular pipe, which serves to make an air-tight communication with the retort, by allowing the tube b, to pass readily through it. From the chamber c, the liquid and gazeous products pass to the tar-chamber, or compartment e, by means of the descending pipe f. The tar and other condensible substances are therefore deposited at e, whilst the gazeous products alone ascend from the tar-chamber e, by the pipe g, and down again the pipe h, (which is closed at the top) into the compartment d, of the vessel or purifier, fig. 2 . The gas being thus made to pass from the compartment e, up into the pipe g, and down the pipe h, (which is closed at the top) into the purifier d, is brought into contact with the liquor in that vessel, where it is opposed to a pressure in proportion to the perpendicular height of the column of liquid which it contains. The funnel in the compartment c, is considerably higher than the purifying apparatus, it therefore allows the liquid which it contains, when pressed upon by the gas, to ascend into it, without overflowing the apparatus, and to descend again as the pressure diminishes—i  is another wide-mouth funnel, by means of which the chamber d, is filled with the alcaline solution, or mixture of lime and water. The carbonic acid gas and sulphuretted hidrogen, evolved during the distillation of the coal, are thus made to combine with the alcali or lime, in the compartment d, of the purifier, forming carbonate and hidro-sulphuret of lime. The carburetted hidrogen, being left more or less pure, is conveyed through the pipe k, into the gasometer, fig. 3 . The communication of the purifier,fig. 2 , with the gasometer, is made by means of the well-known water-valve l, placed so that the communicating tube k, may be easily removed at pleasure—m, is a cock for drawing off the tar, &c. n, a gauge-cock for ascertaining the height of the liquid in the chamber d. The gasometer, fig. 3 , the object of which is to store up the gas, consists of two principal parts—namely, a large interior vessel designed to contain the gas, and an outer cistern or vessel, of rather greater capacity, in which the former is suspended, designed to contain the water by which the gas is confined. The interior vessel which contains the gas is suspended by chains or cords hung over pullies, to which weights are attached, so as to nearly equipoise it. o  is a pipe, which communicates with the water-valve l, and by means of which the gas passes from the purifier, fig. 2 , into the gasometer. The upper end of this pipe is covered, in the manner of a hood, by a cylindrical vessel p, open at bottom, but partially immersed beneath the surface of the water contained in the outer cistern of the gasometer, and perforated round near the lower edge with a number of small holes. The gas displaces the water from this receiver p, and escapes through the small holes, rising in bubbles through the water, so as to expose a large surface to its action, that it may be properly washed, &c. After rising through the water the gas enters the gasometer, which is suspended to move up and down by the chains, pullies, and balance-weights, q. From the centre of the gasometer a tube, r, descends, which includes a pipe, s, fixed perpendicular from the bottom of the cistern. The fixed pipe r, forms a guide to keep the gasometer always perpendicular. t  is also an iron pipe made fast in the centre of the inner vessel, and communicates with the upright tube, s, in the outer vessel. This contrivance obliges the gas to pass into the pipe t, whilst it also serves to keep the gasometer steady when nearly out of the outer cistern.

When the operation commences, the gasometer is sunk down nearly to a level with the surface of the water in the outer cistern, and is consequently filled with water; but as the gas enters, it rises up to receive it. It is to be noted, that the balance-weights q  q, should not be quite so heavy as the gasometer, in order that some pressure may be exerted, to force the gas out of the burners with a proper jet. The gas which issues from the retort enters the purifier as stated already, and ascends the pipe o, into the vessel,p, from which it displaces the water, and passes out at the small holes, as before described, rising through the water into the gasometer, and raising it up: the gas then passes away to the burners, u  u. In this manner the process proceeds until the whole of the volatile products of the coal in the retort is evaporated. The use of the gasometer is, to equalize the emission of the gas which comes from the retort more quickly at some time than others. When this happens, the interior vessel rises up to receive it, and when the stream from the retort diminishes, the weight of the gasometer expels its contents. When the process is finished, the retort is suffered to cool, and its ground stopper is then removed to replenish it with coal. The residue found in the retort is coke. v  v  are cocks to let off any liquid that may collect in the pipe o  or t ; for if the smallest portion of liquid were to obstruct the free passage of the gas to the burners, the consequence would be, that the lights would not burn steadily—they would, as it is called,dance , or become extinguished. x  is the main stop-cock which communicates with the burners—these, of course, may be placed as convenience may require. z  z  are two projecting parts in the top of the gasometer; they are intended to receive the hood p, and the upper extremity of the pipe t, so as to allow the gasometer to be wholly immersed into the cistern. The wheels or pullies of the gasometer have a groove to allow the links of the chain to pass freely.

In this apparatus there is no provision made for the unequal pressure which the gas suffers, accordingly as the gasometer is more or less immersed in water. It will be observed that, in this apparatus, the weight of the interior vessel is constantly increasing, in proportion as it fills with gas, and rises out of the water, and consequently, if a constant, uniform, counterpoising weight, equal only to that of the gasometer in the first moment of its rise, be employed, the gas becomes gradually more and more compressed by that part of the weight of the gasometer which is not counterpoised, and if its pressure or quantity be then estimated by the bulk which it occupies, without making allowance for the increasing pressure, a material error must arise, and this, in the large way, would give rise to insurmountable difficulties with regard to the regulation of the size of the flames; which could not be rendered uniform.

Suppose the cistern or exterior vessel full of water, and the gasometer partly filled with gas and partly with water, it is evident that the balance-weight may be so adjusted, as to occasion an exact equilibrium, so that the external air shall not tend to enter into the gasometer nor the gas to escape from it; and in this case the water will stand exactly at the same level both within the gasometer and within the outer cistern. On the contrary, if the balance-weights be diminished, the gasometer will then press downwards from its own gravity, and the water will stand lower in the gasometer than it does in the cistern; in this case, the included air or gas will suffer a degree of compression above that experienced by the external air, exactly proportioned to the weight of a column of water, equal to the difference of the external and internal surfaces of the water.

To compensate for this increasing weight of the gasometer, and render a scale of equal graduations accurate, some have ingeniously adopted the plan of a spiral pulley to the chain, which has the effect of gradually avoiding the evil, but the best way of accomplishing it will be stated hereafter.

With regard to the philosophy or the production of coal-gas, it proves that pit-coal contains solid hidrogen, carbon, and oxigen. When the intensity of the heat has reached a certain degree, a part of the carbon unites with part of the oxigen and produces carbonic acid, which by means of caloric is melted into the gazeous state and forms carbonic acid gas; at the same time, part of the hidrogen of the coal combines with another portion of carbon and caloric, and forms the carburetted hidrogen gas, which varies considerably in its constitution, according to the circumstances under which it is produced; a portion of olifiant gas, carbonic oxid, hidrogen, and sulphuretted hidrogen, is also produced during the process. The quantities of these products vary according to the nature of the coal employed in the process.

Pit-coal is not the only substance which affords carburetted hydrogen; this gazeous fluid may be obtained in a great variety of ways, and with very considerable differences in specific gravity and proportion of ingredients.

It is found plentifully native or ready formed on the surface of stagnant waters, marshes, wet ditches, &c. through which, if examined closely, large bubbles will be seen to rise in hot weather, and may be increased at pleasure by stirring the bottom or mud with a stick.

In close still evenings if a lighted candle is held over the surface, flashes of blue lambent flame may sometimes be perceived spreading to a considerable distance. All that is not fabulous concerning the ignis fatuus  is probably derived from this source. This species of gas is termed for distinction the carburetted hydrogen of marshes. In the purest form in which it can be collected it is mixed with about 20 per cent. of azot or nitrogen.

To procure the gas for the purpose of philosophical amusement, fill a wide-mouthed bottle with the water of the ditch, and keep it inverted therein with a large funnel in its neck, then with a stick stir the mud at the bottom just under the funnel, so as to cause the bubbles of air which rise from the mud to enter into the bottle; when by thus stirring the mud in various places, the air may be catched in the bottle.

Carburetted hidrogen gas is also given out very abundantly by all kinds of vegetable matter when subjected to a scorching heat sufficient to decompose them. When heated in close vessels much more gas is obtained than when burnt in the open air. If moistened charcoal be put into an earthen retort and heat be applied till the retort becomes ignited; gas will be evolved, consisting partly of carbonic acid, and partly of carburetted hidrogen. A gas of similar properties is obtained by causing steam to pass through a tube filled with red-hot charcoal; by passing spirit of wine, or camphor, through red-hot tubes; by distilling oils, wood, bones, wax and tallow, or any animal or vegetable body whatever.

Indeed it would be endless to enumerate the various sources of this gazeous fluid. A most curious variety of carburetted hidrogen gas has been discovered by the associated Dutch chemists (Van Dieman ,Troostwyck , and others) which is procured from ether or alcohol, and has the remarkable property of generating a heavy oil when in contact with chlorine gas. Hence it has been termed oily carburetted hidrogen, or olifiant gas—it consists of carburetted hydrogen, supersaturated with carbon. The oil generated is heavier than water, whitish, and semi-transparent. By keeping, it becomes yellow and limpid; its smell is highly fragrant and penetrating—its taste somewhat sweet—it is partly soluble in water, imparting to it, its peculiar smell. A portion of this gas always accompanies the common carburetted hidrogen obtained from coal, and those sorts of coal that afford the largest quantity of it are best suited for the production of gas-light.

The nature of carburetted hidrogen obtained from coal varies considerably according to the conditions under which it is obtained. The first part is always much heavier than the last, though still lighter than common air, and holds in solution a portion of oil, for on standing for some time over water it becomes lighter, and is found to require less oxygen for saturation than before. The oil which it held suspended, then becomes precipitated. The average specific gravity of the first and last gas mixed, which may be taken as an average of the whole specific gravity is to that of common air as 2 to 3—112lb. of common cannel coal produce at its minimum , from 350 to 360 cubic feet of carburetted hidrogen gas; but the same quantity of the best Newcastle coal, that is to say, such as coke, which, when laid on the fire readily undergoes a kind of semi-fusion, and sends out brilliant streams of flame, produces upon an average from 300 to 360 cubic feet of this gazeous fluid, besides a large portion of sulphuretted hidrogen, carbonic oxid and carbonic acid. Half a cubic foot of this carburetted hidrogen, fresh prepared, that is to say, holding in solution or suspension, a portion of the essential oil, which is generated during the evolution of the gas, is equal in illuminating power to from 170 to 180 grains of tallow, (being the quantity consumed by a candle six to the pound in one hour.) Now, one pound avoirdupoise is equal to 7000 grains, and consequently one pound of candles of six in the pound, burning one at a time in succession, would last (if we take 175 grains of tallow to be consumed in an hour) 7000 175  = 40 hours. To produce the same light we must burn one half of a cubic foot of coal-gas per hour; therefore, one-half multiplied by forty hours is equal to twenty cubic feet of gas in 40 hours, consequently equal to one pound of candles, six to the pound, provided they were burnt one after another. One hundred and twelve pounds of cannel-coal, produce, at its minimum , three hundred and fifty cubic feet of gas; and are equal to three hundred and fifty, divided by twenty, which last is equivalent to one pound of tallow, making one hundred and twelve pounds of cannel-coal, equal to 350 20  = 17 1 2 lbs. of tallow. Further, one hundred and twelve pounds of cannel-coal, divided by seventeen and a half of tallow make six and four-tenths of cannel-coal, equal to one pound of tallow.

With regard to Newcastle coals [17], it may be stated that one chaldron of Wall's-End coal may be made to produce in the large way upwards of 11,000 cubic feet of crude gas; which, when properly purified, diminishes to nearly 10,000 cubic feet.

[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 during the 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 producing an 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 27  part of its own bulk of pure coal-gas is 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 of olefiant 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. Sobolewsky  and Horrer , 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 with which 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.

Utility of the Gas-Light Illumination, With Regard to Public and Private Economy

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 procuring light 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 nuisance in all our common lights. The products of the combustion are water and carbonic acid gas [21]. The accurate and elegant experiments of Dr. W. Henry  have 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], which sufficiently 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.”

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 below by 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 the house. When transparencies are wanted as decorations for halls, lobbies, &c. more than light, recesses may be filled with different coloured media , 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 many jets 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 the night 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-light mains  extend 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, with gas, 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.

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 the stop-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 opportunity of 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 enabled to 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 water 14°
Carburetted hidrogen, or coal gas 10
Carbonic oxid 4
Hidrogen 5
Spermaceti oil 10 grains burnt in a lamp raised 30,000 grains of water 5
Tallow 5
Wax 5,75
Oil of turpentine 3
Spirit of wine 2

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 too little 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, and allow 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 lamps

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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.

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

Plate  III. fig. 1 , represents a Rod Lamp . The gas passes through the rod a, to the Argand burner, which is surrounded by a cylindrical chimney, c, swelling out at the lower extremity. The construction of the Argand burner we have mentioned already.

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 in fig. 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, b  b c  shows 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 ball b, and pipe, c, of the lamp, fig. 6 .

Fig. 8 A Swing Cockspur Lamp , constructed upon the same plan as fig. 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.

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Plate  IV ,[26] fig. 1 A Candelabrum ; the gas pipe ascending from the floor of the apartment, through the column a, 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, c  c, 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. a  is 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. a  and b, 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 with c, branches out at right angles at d  de  e, are the burners of the lamp.

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Plate  V 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, b  b, 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, c  c.

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-work plateau , 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, at the bottom of which it joins the tubes communicating with the metallic corn-ears, b, at the upper extremities of which it forms jets de feu .

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

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

Sketch of the Rise and Progress of the Discovery and Application of Coal-Gas,As A Substitute for Procuring Artificial Light

To assist the reader in comprehending the nature and object of substituting coal-gas for tallow or oil, for the purpose of obtaining light, it may be proper to touch slightly upon the successive discoveries that have been made as to the decomposition of coal, and the application of its different ingredients. Such a sketch will add to the many examples that occur in the history of science and art, showing the slow progress of mankind in following up known principles, or extracting from acknowledged facts every possible advantage.

In the Philosophical Transactions of the Royal Society, V. XLI. so long ago as the year 1739, is recorded a paper, exhibiting an account of some experiments made by Dr. James Clayton, from which it appears that the inflammable nature of coal-gas was then already known. Dr. Clayton having distilled Newcastle coal, obtained, as products of the process, an aqueous fluid, a black oil, and an inflammable gas, which he caught in bladders, and by pricking these he was enabled to inflame the gas at pleasure.

It is further known, that in the beginning of the last century, Dr. Hales [11] on submitting pit-coal to a chemical examination, found, that during the ignition of this fossil in close vessels, nearly one-third of the coal became volatilized in the form of an inflammable vapour. Hence the discovery of the inflammable nature of coal-gas can no longer be claimed by any person now living.

[11]Vegetab. Statics, vol. I.

In the year 1767, the Bishop of Llandaff [12] examined the nature of the vapour and gazeous products evolved during the distillation of pit-coal. This learned philosopher noticed, that the volatile product is not only inflammable as it issues from the distillatory vessel, but that it also retained its inflammability after having been made to pass through water, and suffered to ascend through two high curved tubes. The solid matters obtained by this venerable prelate, were, an aqueous ammoniacal fluid, a tenaceous oil, resembling tar, an ammoniacal liquor, and a spongy coal, or coke.

[12]Watson's Chemical Essays, vol. II.

The first discovery and application of the use of coal-gas for the purpose of illumination is claimed by Mr. Murdoch.

Dr. W. Henry of Manchester, has published the following account [13] of this discovery.

[13]Thompson's System of Chemistry, vol. I. p. 52.

“In the year 1792, at which time Mr. Murdoch resided at Redruth, in Cornwall, he commenced a series of experiments upon the quantity and quality of the gases contained in different substances. In the course of these he remarked, that the gas obtained by distillation from coal, peat, wood, and other inflammable substances, burnt with great brilliancy upon being set fire to; and it occurred to him, that by confining and conducting it through tubes, it might be employed as an economical substitute for lamps and candles. The distillation was performed in iron retorts, and the gas conducted through tinned iron and copper tubes to the distance of 70 feet. At this termination, as well as at intermediate points, the gas was set fire to, as it passed through apertures of different diameters and forms, purposely varied with a view of ascertaining which would answer best. In some the gas issued through a number of small holes like the head of a watering pan; in others it was thrown out in thin long sheets; and again in others in circular ones, upon the principle of Argand's lamp. Bags of leather and of varnished silk, bladders, and vessels of tinned iron, were filled with the gas, which was set fire to, and carried about from room to room, with a view of ascertaining how far it could be made to answer the purpose of a moveable or transferable light. Trials were likewise made of the different quantities and qualities of gas produced by coals of various descriptions, such as the Swansea, Haverfordwest, Newcastle, Shropshire, Staffordshire, and some kinds of Scotch coals.

“Mr. Murdoch's constant occupations prevented his giving farther attention to the subject at that time; but he again availed himself of a moment of leisure to repeat his experiments upon coal and peat at Old Cumnock, in Ayrshire, in 1797; and it may be proper to notice that both these, and the former ones, were exhibited to numerous spectators, who, if necessary, can attest them. In 1798, he constructed an apparatus at Soho Foundry, which was applied during many successive nights to the lighting of the building; when the experiments upon different apertures were repeated and extended upon a large scale. Various methods were also practised of washing and purifying the air, to get rid of the smoke and smell. These experiments were continued, with occasional interruptions, until the epoch of the peace in the spring of 1802, when the illumination of the Soho manufactory afforded an opportunity of making a public display of the new lights; and they were made to constitute a principal feature in that exhibition.”

In the year 1803 and 1804, Mr. Winsor exhibited at the Lyceum in London the general nature of this new mode of illumination though the machinery for procuring, and the manner of purifying the gas, he kept a secret. He exhibited the mode of conducting the gas through the house, and a number of devices for chandeliers, lamps, and burners, by which it might be applied. Among these he proposed long flexible tubes suspended from the ceiling, or wall of the room, and at the end communicating with burners or lamps of different kinds. This gentleman showed also by experiment, that the flame of the gas-light, produced no smoke; that it was not so dangerous as the flame of candles or lamps; that it could not produce sparks; and that it was not so readily extinguished by gusts of wind or torrents of rain.

Mr. Winsor 's display of gas-lights took place more than two years before Mr. Murdoch 's priority of right was heard of.

In stating these facts I do not mean to say that Mr. Murdoch  derived the hint of applying the coal-gas from the previous exhibition of Mr. Winsor , because it is quite within the bounds of probability that the ideas of Mr. Murdoch  may have arisen totally independent of all acquaintance with Mr. Winsor 's.

The claims of invention, or the determination of the right of priority, concerns the public only so far as the honour and estimation of any useful discovery conferred on the inventor may induce other individuals to devote their talents to similar pursuits; by means of which, more discoveries may be made, and the subject of human invention become extended, or rendered more useful. For as the mere benefits which mankind may derive from any particular discovery, they are certainly more indebted to the person who first applied the discovery to actual practice, than to him who first made it, and merely illustrated it by barren experiments. Mr. Winsor  certainly pressed on the mind of the public with unremitted perseverance and diligence the extensive application of gas-light in the year 1802, but he made no new discovery with regard to the composition of coal; he did not even invent the mode of conducting the gas through tubes; and if he has pointed out the particulars of the process, he has made a very important, though not the most brilliant improvement in this line of business. Mr. Winsor 's publications are, perhaps, but ill adapted to promote his cause; and the exaggerated calculation which the sanguine mind of a discoverer is naturally disposed to indulge in, have, to superficial observers, thrown an air of ridicule and improbability on the whole scheme of lighting with gas.

It may, however, be safely affirmed, that if the same facts had come forward, under the sanction of some great name in the chemical or philosophical world, the public incredulity would long since have been subdued; and the plan, which for many years has been struggling for existence, would have been eagerly adopted as a national object.

On the 18th of May, 1804, Mr. Frederick Albert Winsor , took out a patent for combining the saving and purifying of the inflammable gas (for producing light and heat), the ammonia, tar, and other products of pit-coal, with the manufacture of a superior kind of coke (see Repertory, 2d Series, v. 172). And, lately, the same gentleman has taken out a second patent, for further improvements in these processes.

In the year 1805, Mr. Northern , of Leeds, also directed the attention of the public to the application of coal-gas, as a substitute for tallow light, as will be seen by the following extract of the Monthly Magazine for April, 1805.

“I distilled in a retort, 50 ounces of pit-coal in a red heat, which gave 6 ounces of a liquid matter covered with oil, more or less fluid as the heat was increased or diminished. About 26 ounces of cinder remained in the retort; the rest came over in the form of air, as it was collected in the pneumatic apparatus. I mixed part of it with atmospherical air, and fired it with the electric spark with a tolerable explosion, which proves it to be hydrogene.—Whether any of the other gases were mixed with it, I did not then determine. In the receiver I found a fluid of an acid taste, with a great quantity of oil, and, at the bottom, a substance resembling tar.

“The apparatus I make use of for producing light is a refiner's crucible, the top of which (after filling with coal) I close with a metal cover, luted with clay or other luting, so as to prevent the escape of the gas; a metal pipe is soldered into the cover, bent so as to come under the shelf in the pneumatic trough, over which I place a jar with a stop-cock and a small tube; the jar being previously filled with water, the crucible I place on the common or other fire as is most convenient; and as the heat increases in it, the gas is forced rapidly through the water into the jar, and regularly displaces it. I then open the cock and put fire to the gas, which makes its escape through the small tube, and immediately a most beautiful flame ensues, perfectly free from smoke or smell of any kind. A larger light, but not so vivid or clear, will be produced without passing the gas through water, but attended with a smoke somewhat greater than that of a lamp charged with common oil.

“I have great hopes that some active mechanic or chemist will, in the end, hit on a plan to produce light for large factories, and other purposes, at a much less expence, by the above or similar means, than is at present produced from oil.”

Soon afterwards, Mr. Samuel Clegg [14] of Manchester, Engineer, communicated an account of his method of lighting up manufactories with gas-light to the Society of Arts, for which he received the silver medal.

[14]This gentleman is at present engineer to the Gas-Light Company.

Since that time, the application of gas-light has spread rapidly, and numerous manufactories and other establishments have been lighted by coal-gas.

In France, the application of gas-lights to economical purposes, was pointed out long before it was publicly introduced into this country. M. Le Bon  had a house fitted up in Paris, in the winter of 1802, so as to be entirely illuminated by gas-lights, which was seen by thousands with admiration; and had a brevet d'invention  (patent) granted to him by the French government, for the art of producing light from wood, ignited in close vessels.

Many other attempts have been made to derive advantage from the different ingredients of coal; but they are too obscure to merit particular enumeration.

In the year 1808, Mr. Murdoch  presented to the Royal Society his account of the application of gas-light, and was complimented with Count Romford 's medal for the same.

The following statement is taken from Mr. Murdoch 's paper.

“The whole of the rooms of the cotton mill of Mr. Lee , at Manchester, which is I believe the most extensive in the United Kingdom, as well as its counting-houses and store-rooms, and the adjacent dwelling house of Mr. Lee , are lighted with the gas from coal. The total quantity of light used during the hours of burning has been ascertained, by a comparison of shadows, to be about equal to the light which 2500 mould candles, of six to the pound, would give; each of the candles with which the comparison was made consuming at the rate of 4-10ths of an ounce (175 grains) of tallow per hour.

“The gas-burners are of two kinds: the one is upon the principle of the Argand lamp, and resembles it in appearance; the other is a small curved tube with a conical end, having three circular apertures or perforations, of about a thirtieth of an inch in diameter, one at the point of the cone, and two lateral ones, through which the gas issues, forming three divergent jets of flame, somewhat like a fleur-de-lis. The shape and general appearance of this tube has procured it, among the workmen, the name of the cockspur burner.

“The number of burners employed in all the buildings amounts to 271 Argand, and 653 cockspurs, each of the former giving a light equal to that of four candles of the description above-mentioned; and each of the latter a light equal to two and a quarter of the same candles; making therefore the total of the gas-light a little more than equal to that of 2500 candles, six to the pound. When thus regulated, the whole of the above burners require an hourly supply of 1250 cubic feet of the gas produced from cannel-coal; the superior quality and quantity of the gas produced from that material having given it a decided preference in this situation over every other coal, notwithstanding its higher price.

“The time during which the gas-light is used may, upon an average of the whole year, be stated at least at two hours per day of 24 hours. In some mills, where there is over work, it will be three hours; and in the few where night work is still continued nearly 12 hours. But taking two hours per day as the common average throughout the year, the consumption in Messrs. Philips and Lee's mill will be 1250 × 2 = 2500 cubic feet of gas per day; to produce which 700 weight of cannel-coal is required in the retort. The price of the best Wiggan cannel-coal (the sort used) is 13 1 2 d. per cwt. (22 s. 6 d. per ton) delivered at the mill, or say about eight shillings for the seven hundred weight. Multiplying by the number of working days in the year (313,) the annual consumption of coal will be 110 tons, and its cost 125 l.

“About one-third of the above quantity, or say forty tons of good common coal, value ten shillings per ton, is required for fuel to heat the retorts, the annual amount of which is 20 l.

“The 110 tons of cannel-coal, when distilled, produce about 70 tons of good coke, which is sold upon the spot at 1 s. 4 d. per cwt. and will therefore amount annually to the sum of 93 l.

“The quantity of tar produced from each ton of cannel-coal is from 11 to 12 ale gallons, making a total annual produce of about 1250 ale gallons, which not having been yet sold, it cannot yet be determined its value.

“The interest of the capital expended in the necessary apparatus and buildings, together with what is considered as an ample allowance for wear and tear, is stated by Mr. Lee  at about 550 l. per annum, in which some allowance is made for this apparatus being made upon a scale adequate to the supply of a still greater quantity of light, than he has occasion to make use of.

“Mr. Lee  is of opinion that the cost of attendance upon candles would be as much, if not more, than upon the gas apparatus; so that, in forming the comparison, nothing need be stated upon that score, on either side.

“The economical statement for one year, then, stands thus:

Cost of 110 tons of cannel coal £ 125
Ditto of 40 tons of common ditto, to carbonise 20
In all 145
Deduct the value of 70 tons of coke 93
The annual expenditure in coal, after deducting the value of the coke, and without allowing any thing for the tar, is therefore 52
And the interest of capital sunk, and wear and tear of apparatus 550
Making the total expence of the gas apparatus per annum, about 600

“That of candles, to give the same light, would be about 2000 l. For each candle, consuming at the rate of 4-10ths of an ounce of tallow per hour, the 2500 candles burning, upon an average of the year, two hours per day, would, at one shilling per pound, the present price, amount to nearly the sum of money above-mentioned.

“If the comparison were made upon an average of three hours per day, as in most cases, would perhaps be nearer to the truth, and the tear and wear remaining nearly the same as on the former case, the whole cost would not exceed 650 l. while that of the tallow would be 3000 l.

Mr. Ackerman  in this metropolis, has shown that the art of gas-light illumination is not confined to great manufactories, but that its advantages are equally applicable to those on a moderate scale. The whole of Mr. Ackerman 's establishment, his public library, warehouse, printing-offices and work-shops, together with his dwelling house, from the kitchen to the drawing-room, has, for these four years past, been lighted with gas, to the total exclusion of all other lights. The result of the whole of this proceeding will be obvious from the following letter:

To Mr. ACCUM.

Sir ,

“In answer to your request with regard to my gas-lights, which I now have in my house, I take this mode of informing you, that I charge two retorts with 240lbs. of coal, half cannel and half Newcastle, from which I extract 1000 cubic feet of gas. To obtain this quantity of gas, when the retorts are cold, I use from 100 to 110lb. of common coals; but when they are in a working state, that is to say, when they are once red hot, the carbonising fuel amounts to about 25lb. per retort. The bulk of gas thus obtained supplies 40 Argand's lamps, of the large size, for four hours per night, during the long winter evenings, together with eight Argand's lamps and about 22 single cockspur burners, for three hours per night: in addition to which my printers employ 16 cockspur burners for ten hours per day to heat their plates instead of charcoal fire. In the depth of winter we charge two retorts per day: but, upon an average, we work 365 retorts in 365 days.

Now 365 retorts containing 120lb. of coal each, make 43800lb. which is equal to ten chaldrons of Newcastle and eight tons of cannel coal.

10 chaldrons of Newcastle coals, at 65s. make £ 32 10 0
8 tons of cannel coal,[15] (this coal is sold by weight) at 100s. per ton 40 0 0
7 chaldrons of common coals for carbonising, at 55s.19 5 0
To wages paid the servant for attending the gas apparatus 30 0 0
Interest of money sunk 30 0 0
 The wear and tear of the gas-light apparatus I consider to be equal to the wear and tear of lamps, candlesticks, &c. employed for oil, tallow, &c. 
Total expence of the gas lights 151 15 0
DEDUCT
23 chaldrons of coke, at 60s. per chaldron 69  
Ammoniacal liquor 5  
Tar 6  
Charcoal employed by the copper-plate printers to heat their plates, which is now done with the gas-light flame, cost, annually 25  
Two chaldrons of coals minus  used as fuel, for warming the house, since the adoption of the gas-lights, at 65s. per chaldron 6 10  
 111 10 0
Nett expences of the gas-lights £ 40 5 0
The lights used in my Establishment, prior to the gas-lights, amounted annually to 160 0 0
My present system of lighting with gas costs, per ann.40 5 0
Balance in favor of the gas for one year £ 119 15 0

[15]Although cannel-coal sells at nearly double the price of Newcastle coal, I use it in preference to the latter, because it affords a larger portion of gas, and gives a much more brilliant light.

Such is the simple statement of my present system of lighting, the brilliancy of which, when contrasted with our former lights, bears the same comparison to them as a bright summer sun-shine does to a murky November day: nor are we, as formerly, almost suffocated with the effluvia of charcoal and fumes of candles and lamps. In addition to this, the damage sustained by the spilling of oil and tallow upon prints, drawings, books and paper, &c. amounted annually to upwards of 50l. All the workmen employed in my establishment consider their gas-lights as the greatest blessing; and I have only to add, that the light we now enjoy, were it to be produced by means of Argand's lamps or candles, would cost at least 350l. per annum.

I am, with respect,
Yours,

Strand, March 13,
1815.

R. ACKERMAN.”

Another manufacturer who was one of the first that adopted the use of this method of illumination in the small way, and who gave a statement of its advantages to the public, is Mr. Cook , a manufacturer of metal toys, at Birmingham, a clear-headed, prudent man, not apt to be dazzled by a fanciful speculation, but governed in his transactions by a simple balance of profit and loss. There is a naïveté in his own account of the process which will amuse as well as instruct the reader.

“My apparatus is simply a small cast-iron pot, of about eight gallons, with a cast-iron cover, which I lute to it with sand. Into this pot I put my coal. I pass the gas through water into the gasometer or reservoir, which holds about 400 gallons; and, by means of old gun-barrels, convey it all round my shops. Now, from twenty or twenty-five pounds of coal, I make perhaps six hundred gallons [16] of gas; for, when my reservoir is full, we are forced to burn away the overplus in waste, unless we have work to use it as it is made: but, in general, we go on making and using it, so that I cannot tell to fifty or a hundred gallons;—and, in fact, a great deal depends on the coals, some coals making much more than others. These twenty-five pounds of coal put into the retort, and say twenty-five pounds more to heat the retort, which is more than it does take one time with another, but I am willing to say the utmost, are worth four-pence per day. From this four-pence we burn eighteen or twenty lights during the winter season.”

[16]A wine-gallon is equal to 231 cubic inches.

Thus are the candles which Mr. Cook  used to employ, and which cost him three shillings a day, entirely superseded. But, besides his expence in candles, oil and cotton for soldering, used to cost him full 30 l. a year; which is entirely saved, as he now does all his soldering by the gas flame only. For “in all trades in which the blow-pipe is used with oil and cotton, or where charcoal is employed to produce a moderate heat, the gas flame will be found much superior, both as to quickness and neatness in the work: the flame is sharper, and is constantly ready for use; while, with oil and cotton or charcoal, the workman is always obliged to wait for his lamp or coal getting up; that is, till it is sufficiently on fire to do his work. Thus, a great quantity of oil is always burned away useless; but, with the gas, the moment the stop-cock is turned, the lamp is ready, and not a moment is lost.” We must refer to Mr. Cook 's letter for the details of expence, which he gives with faithful minuteness, and always leaning to the side unfavourable to the gas. The result of the whole is, that he saves 30 l. out of the 50 l. which his lights formerly cost him: and, when we consider that his calculation allows the gas-lights to burn the whole year, and the candles only twenty weeks, there can be little doubt, that the savings in this case follow nearly the same proportion as in the former. If the apparatus be erected even on a smaller scale, “the saving,” Mr. Cook  assures us, “will still be considerable: for the poor man, who lights only six candles, or uses one lamp, if the apparatus is put up in the cheapest way possible, will find it only cost him 10 l. or 12 l. which he will nearly, if not quite, save the first year.”

Mr. Ackerman  having, in this town, set the example of lighting his establishment with gas, several other individuals soon followed the attempt. The following statement will show, that this species of light may be made use of with the greatest advantage, upon a still smaller scale, where no great nicety with regard to the apparatus for procuring gas is required. The following report I have received from Messrs. Lloyd , of Queen Street, Southwark, thimble manufacturers and whitesmiths, who have used the gas-light for soldering and other purposes these five years past.

From 4 pecks or 1 bushel of coals, weighing 69lbs. for which we now pay (1809) 1s. we produce 4 3 4  pecks of coke and 1 2  peck of coal not carbonised remains in the distilling pot, which together with the coke weighs 58lbs. 6 oz. value at 1s. per bushel 0 1 4
we procure 6lbs. 4 oz. of tar which we use as pith—it saves us 0 1 0
 0 2 4
Deduct for coal 0 1 0
Profit on coke and tar 0 1 0
The gas yielded by the 4 pecks of coals in the pot, make 42 brilliant lights, which burn 7 hours. To keep 42 tallow candles which were formerly used in the manufactory burning for the same time, required 7lbs. which at 1s. per lb. cost 0 7 0
To this, add profits on coke and tar 0 1 0
Gained out of every bushel of coal 0 8 0

“The gas-burners made use of in our manufactory produce jets of flame, which in our business, where much soldering with the blow-pipe must be done, have a decided superiority over Argand's lamps. We are not nice concerning the quality of the gas—a great part of it is burned from the gasometer, without allowing it to purify itself in the gasometer, because our gasometer is not large enough to store up the whole quantity of gas we want for use.”