A
PRACTICAL TREATISE
ON
GAS-LIGHT;
EXHIBITING
A SUMMARY DESCRIPTION
OF THE
APPARATUS AND MACHINERY
BEST CALCULATED FOR
ILLUMINATING
STREETS, HOUSES, AND MANUFACTORIES,
WITH
CARBURETTED HYDROGEN, OR COAL-GAS,
WITH REMARKS
ON THE
UTILITY, SAFETY, AND GENERAL NATURE OF THIS NEW BRANCH
OF CIVIL ECONOMY.
By FREDRICK ACCUM,
OPERATIVE CHEMIST,
LECTURER ON PRACTICAL CHEMISTRY, ON MINERALOGY, AND ON CHEMISTRY
APPLIED TO THE ARTS AND MANUFACTURES; MEMBER OF THE ROYAL
IRISH ACADEMY, FELLOW OF THE LINNÆN SOCIETY, MEMBER
OF THE ROYAL ACADEMY OF SCIENCES OF BERLIN, &c. &c.
WITH SEVEN COLOURED PLATES.
London:
PRINTED BY G. HAYDEN, BRYDGES-STREET, COVENT GARDEN;
FOR R. ACKERMANN, 101, STRAND;
LONGMAN, HURST, REES, ORME, AND BROWN; AND SHERWOOD, NEELY, AND
JONES, PATERNOSTER ROW; AND J. HATCHARD, PICCADILLY.
Price—Twelve Shillings in Boards.
1815.
EX FUMO DARE LUCEM.
Hor.
PREFACE.
11, Compton Street Soho.
The following pages are intended to exhibit a summary view of the new art of procuring light, by means of carburetted hydrogen gas obtained from pit-coal, and which of late has been employed with unparalelled success, as a substitute for candles and lamps, and is known by the name of Gas-Light.
To accomplish this object, I have given, in the first part of this Essay, a concise and popular view of the chemical theory and production of artificial light—I have explained the action of candles and lamps—I have shown the methods of measuring the comparative illuminating power of artificial light of different kinds, so as to appreciate their economical value—I have stated the proportions of combustible materials requisite for producing a light of a certain strength; with such other preliminary facts and observations as were deemed necessary to enable the reader to understand fully the nature of the new art of illumination, which it is the object of this Essay to describe.
These positions are followed by a chemical view of the general nature and composition of coal—the chemical changes which this substance suffers, when employed in the production of gas-light—the different products it furnishes—the modes of obtaining them—their properties and applications in the various arts of life.
I have given a description of the apparatus and machinery by means of which the coal-gas is prepared, and the methods employed for distributing and applying it as a substitute for candles and lamps to illuminate houses, streets and manufactories;—I have furnished the data for calculating the expense that must attend the application of this species of light under different circumstances, so as to determine the relative cost or value of gas-lights, when compared with the lights now in use—together with such other practical directions and facts as will enable the reader to form a proper estimate of the gas-light illumination, and to put this art into practice.
I have stated the leading objects of public and private utility to which the new system of lighting may be successfully applied, candidly pointing out those in which it cannot be made use of to advantage.
I have detailed the most obvious effects which the discovery of lighting with coal-gas must inevitably produce upon the arts and upon domestic economy; its primary advantages—its views—its limits, and the resources it presents to industry and public economy. I have endeavoured to show how far its application is safe, and in what respect it is entitled to public approbation and national encouragement.
It may not be improper, before concluding, to inform the reader, that my qualifications for the task I have undertaken are founded upon many years experience, during which time, I possessed peculiar opportunities to witness and verify the most extended series of operations that ever have been made for the purpose of ascertaining the practicability, safety, and general nature of the art of applying coal-gas as a substitute for tallow and oil; and which have, as it were, fixed the fate of this art. The numerous experiments I instituted, upon a large scale, by desire of the Gas-Light Company, for the purpose of adducing them in my evidence before the House of Commons, and House of Lords, on a former occasion, have enabled me to collect such information as could not have been obtained by other means. The substance of these results (which are printed by order of Government,) are incorporated in this Treatise, together with such other facts and observations as have presented themselves in the routine of my profession elsewhere.
To generalize the results of my observations, and to make them practically useful to the public, is the aim of the present publication, and I need scarcely add, that their suffrages to the zeal and industry, at least, with which I have endeavoured to attain my object, will be a source of infinite satisfaction.
FREDRICK ACCUM
Contents.
INTRODUCTORY OBSERVATION. Page 1. Progress of the arts.—Influence of it upon the morals and condition of man.—Beneficial tendency of chemical and mechanical improvements.—State of pre-eminence of people with regard to civilization.—How to be estimated.—Flourishing state of those nations which have shown the greatest activity in cultivating the useful arts, and establishing useful enterprises.—General observations on this subject.—Extraordinary discoveries of modern times.—New art of procuring light.—Object of the treatise. PART I. PRODUCTION OF ARTIFICIAL LIGHT, &c. 8. Production of the flame generated during the combustion of certain bodies.—Characters of flame when perfect.—Most luminous flame, how produced with the least consumption of combustible matter.—Conditions necessary for that purpose.—Importance of this subject, with regard to the production and supply of artificial light.—The flame of bodies may be tinged.—Blue flame, red flame, green flame, &c.—Opinion concerning the origin of light emitted by bodies burning withERRATA.
Page 24, line 11, for too, read two. 48, 22, for corporated, read incorporated. 53, 7, for this combustion, read the combustion. 64, 24, for Cleg, read Clegg. ibid 25, for communicates, read communicated. 65, erase the * and put it after the word Clegg, line 24, p. 64. ibid 17, for attemps, read attempts. 125, 23,DIRECTIONS TO THE BINDER:
Plate I. facing the title; plate II. facing page 79; plate III. facing page 115; plate IV. facing page 119; plate V. facing page 120; and plates VI. and VII. at the end of the book.
A
PRACTICAL TREATISE
ON
GAS-LIGHT.
INTRODUCTORY OBSERVATION.
INFLUENCE
OF
THE PROGRESS OF THE ARTS
UPON THE
MORALS AND CONDITION OF MAN.
It is an undoubted truth, that the successive improvements in the condition of man, from a state of ignorance and barbarism, to that of the highest cultivation and refinement, are usually effected by the aid of machinery and expedients, calculated to procure the necessaries, the comforts, and the elegancies of life; and that the pre-eminence of any people in civilization is, and ought ever to be, estimated by the proportional state of industry, and useful labour existing among them.
In proof of this great and striking truth, no other argument requires to be offered, than an immediate reference to the experience of all ages and places: the various nations of the earth, the provinces of each nation, the towns, and even the villages of the same province, differ from each other in their accommodations; and are in every respect more flourishing, the greater their activity in establishing new channels of useful employ, calculated to procure the necessaries and comforts of life. Hence the nations which have shewn the most ingenuity in this way, are not only the richest, but also the most populous and the best defended: the provinces of those nations, are seen to flourish likewise in proportion to their respective degrees of activity in this respect, And from these exertions it is, as Smith[1] emphatically remarks, that “the accommodation of an European prince does not always so much exceed that of an industrious and frugal peasant, as the accommodation of the latter exceeds that of many an African king, the absolute master of the lives and liberties of ten thousand naked savages.”
[1] Wealth of Nations, chap. 1.
It was a strange notion of Rousseau to maintain that mankind were happier when they resembled wild beasts, than with all the expanded knowledge of civilized life; and that the cultivation of their understanding had tended to degenerate their virtues. There can be no virtue but what is founded on a comprehensive estimate of the effects of human actions, and an animal under the guidance of instinct can form no such estimate.
The variety of production, of wants, and fabrication of a civilized society, has given rise to barter or exchange; mutual supply has increased the sub-division of labour, and improved the means of conveyance. Streams, roads, ships, and carriages have extended their beneficial intercourse; confidence between man and man has advanced the moral principles of society, and afforded a progression, of which the past gradation may indeed be traced, but to the future part of which the imagination can scarcely form a probable outline. And as the moral and physical powers of man expand, new resources and new agencies are made subservient to our commands, which, in an earlier state of society, would have appeared altogether visionary.
Who among the ancients would have listened to the extraordinary scheme of writing books with such rapidity, that one man, by this new art, should perform the work of twenty thousand amanuenses? What philosopher would have given credit to the daring project of navigating the widest ocean?—or imagined the astonishing effect of gun-powder—or the extended application of the steam engine? What mortal would have dared to dive to the bottom of the sea—or to soar aloft into the air—or bid defiance to the thunder of the clouds? Discoveries which have changed, as it were, the course of human affairs, and the effects of which have already carried the intellectual operations of the human mind, to a height they could by no other means have attained. The men of those early ages, in the confidence of their own wisdom, might have derided these discoveries as impossible, or rejected them as visionary; but to those, who enjoy the full effects of such, and numerous other successful inventions, it becomes a duty to reason upon different principles, and to exert all means in their power to give effect to the progress of useful knowledge.
The artificial production and supply of light during the absence of the sun, unquestionably holds a distinguished rank among the most important arts of civilized life.
If we could for a moment suppose the privation of artificial light, it would follow as an immediate consequence that the greatest part of the globe on which we dwell, would cease to be the habitation of man. Whether he could ensnare or overtake those animals upon whose unprepared remains he would then be compelled to feed—whether he might store the fruits of the earth for his winter supply—what might be the physical and moral consequences of a state of such desolation, may perhaps be conjectured; but no estimate can show its dreadful magnitude. How much do our comforts, and how greatly does the extent of our powers, in the common affairs of life, depend upon the production and supply of artificial light. The flame of a single candle animates a family, every one follows his occupation, and no dread is felt of the darkness of night. It might be a curious speculation to enquire how far, and in what respects, the morals of men would become degraded by the want of this contrivance. But it is sufficient on the present occasion, that, previous to entering upon a dissertation respecting a new art of illumination, a train of ideas has slightly been
The scheme of lighting houses, streets, and manufactories, by means of the inflammable gas, obtainable by distillation from common pit-coal, professes to increase the wealth of the nation, by adding to the number of its internal resources, and on this ground it is entitled, at least, to a candid examination.
The apparent slight that has been thrown upon this new breach of civil economy by some individuals, who appear to be incapable of judging of its nature, has contributed to deter sensible and well disposed persons from wishing it success. It is the more necessary to state this fact, because, when a mistaken notion once becomes diffused, concerning the nature of a new project, persons of the best intention are liable to become affected with wrong impressions on their mind. I am neither a share holder, nor a governor, nor am I directly or indirectly concerned in any gas-light association.
The object of the succeeding pages, simply is to rescue the art of illumination with coal-gas from misconception and misrepresentation, and by a fair, and not overcharged statement of its merits and its disadvantages, to appeal from prejudice and ignorance, to the good sense of the community.
PART I.
PRODUCTION
OF
ARTIFICIAL LIGHT;
AND
THEORY
OF THE
ACTION OF CANDLES AND LAMPS.
The flame of burning bodies consists of such inflammable matter in the act of combustion as is capable of existing in a gazeous state. When all circumstances are favorable to the complete combustion of the products, the flame is perfect; if this is not the case, part of the combustible body, capable of being converted into the gazeous state, passes through the luminous flame unburnt, and exhibits the appearance of smoke. Soot therefore always indicates an imperfect combustion. Hence flame is produced from those inflammable substances only, which are either totally volatile when heat is applied to them, so as not to alter their chemical habitudes—or which contain a quantity of combustible matter that is readily volatilized into vapour by heat, or the elements necessary for producing such vapour or gazeous products, when the chemical constitution of the body is altered by an increase of temperature. And hence the flame of bodies is nothing else than the inflammable product, either in a vaporous or in a permanently elastic gazeous state. Thus originates the flame of wood and coal, when they are burned in their crude state. They contain the elements of a quantity of inflammable matter, which is capable of assuming the gazeous state by the application of heat, and subsequent new chemical arrangements of their constituent parts.
As the artificial light of lamps and candles is afforded by the flame they exhibit, it seems a matter of considerable importance to society, to ascertain how the most luminous flame may be produced with the least consumption of combustible matter. There does not appear to be any danger of error in concluding, that the light emitted will be greatest when the matter is completely consumed in the shortest time. It is therefore necessary, that the stream of volatilized combustible gazeous matter should pass into the atmosphere with a certain determinate velocity. If the quantity of this stream should not be duly proportioned; that is to say, if it be too large, its internal parts will not be completely burned for want of contact with the air. If its temperature be below that of ignition, it will not, in many cases, burn when it comes into the open air. And there is a certain velocity at which the quantity of atmospherical air which comes in contact with the vapour will be neither too great nor too small; for too much air will diminish the temperature of the stream of combustible matter so much as very considerably to impede the desired effect, and too little will render the combustion languid.
We have an example of a flame too large in the mouths of the chimneys of furnaces, where the luminous part is merely superficial, or of the thickness of about an inch or two, according to circumstances, and the internal part, though hot, will not set fire to paper passed into it through an iron tube; the same defect of air preventing the combustion of the paper, as prevented the interior fluid itself from burning. And in the lamp of Argand we see the advantage of an internal current of air, which renders the combustion perfect by the application of air on both sides of a thin flame. So likewise a small flame is always whiter and more luminous than a larger; and a short snuff of a candle giving out less combustible matter in proportion to the circumambient air; the quantity of light becomes increased to eight or ten times what a long snuff would have afforded.
The light of bodies burning with flame, exists previously either combined with the combustible body, or with the substance which supports the combustion. We know that light exists in some bodies as a constituent part, since it is disengaged from them when they enter into new combinations, but we are unable to obtain in a separate state the basis with which it was combined.
That in many cases the light evolved by artificial means is derived from the combustible body, is obvious, if we recollect that the colour of the light emitted during the process of combustion varies, and that this variation usually depends not upon the medium which supports the process of combustion, but upon the combustible body itself. Hence the colour of the flame of certain combustibles, even of the purest kind may be tinged by the admixture of various substances.
The flame of a common candle is far from being of an uniform colour. The lowest part is always blue; and when the flame is sufficiently elongated, so as to be just ready to smoke, the tip is red or brown.
As for the colours of flames that arise from coals, wood, and other usual combustibles, their variety, which hardly amounts to a few shades of red or purple, intermixed with the bright yellow light, seems principally to arise from the greater or less admixture of aqueous vapour, dense smoke, or, in short, of other incombustible products which pass through the luminous flame unburnt.
Spirit of wine burns with a blueish flame. The flame of sulphur has nearly the same tinge. The flame of zinc is of a bright greenish white. The flame of most of the preparations of copper, or of the substances with which they are mixed, is vivid green. Spirit of wine, mixed with common salt, when set on fire, burns with a very unpleasant effect, as may be experienced by looking at the spectators who are illuminated by such light. If a spoonful of spirit of wine and a little boracic acid, or nitrate of copper be stirred together in a cup, and then be set on fire, the flame will be beautifully green. If spirit of wine be mixed with nitrate of strontia, it will, afterwards, on being inflamed, burn with a carmine red colour. Muriate of lime tinges the flame of burning spirit of wine of an orange colour.
[2] See Chemical Amusement, comprising minute instructions for performing a series of striking and interesting chemical experiments, p. 8, &c.
Before we consider the general nature of Gas-Light, it will be necessary to give a short sketch of the theory and action of the instruments of illumination employed for supplying light, together with some other facts connected with the artificial production and distribution of light; such a proceeding will enable us to understand the general nature of the new system of illumination which it is the object of this Essay to explain.
To procure light for the ordinary purposes of life, we are acquainted with no other ready means than the process of combustion.
The rude method of illumination consists, as is sufficiently known, in successively burning certain masses of fuel in the solid state: common fires answer this purpose in the apartments of houses, and in some light-houses. Small fires of resinous wood, and the bituminous fossil, called canel-coal, are in some countries applied to the same end, but the most general and useful contrivance is that in which fat, or oil, of an animal or vegetable kind is burned by means of a wick, and these contrivances comprehend candles and lamps.
In the lamp the combustible substance must be one of those which retain their fluidity at the ordinary temperature of the atmosphere. The candle is formed of a material which is not fusible but at a temperature considerably elevated.
All these substances must be rendered volatile before they can produce a flame, but for this purpose it is sufficient to volatilize a small quantity of any of them, successively; for this small quantity will suffice to give a useful light, and hence we must admire the simple, yet wonderful contrivance of a common candle or lamp. These bodies contain a considerable quantity of the combustible substance, sufficient to last several hours; they have likewise, in a particular place, a slender piece of spongy vegetable substance, called the wick, which in fact is the fire-place, or laboratory where the whole operation is conducted.
There are three articles which demand our attention in the lamp—the oil, the wick, and the supply of air. It is required that the oil should be readily inflammable; the office of the wick appears to be chiefly, if not solely, to convey the oil by capillary attraction to the place of combustion; as the oil is decomposed into carburetted hydrogen gas and other products, other oil succeeds, and in this way a continual current and maintenance of flame is effected.
When a candle is for the first time lighted, a degree of heat is given to the wick, sufficient first to melt, and next to decompose the tallow surrounding its lower surface; and just in this part the newly generated gas and vapour is, by admixture with the air, converted into a blue flame; which, almost instantaneously encompassing the whole body of the vapour, communicates so much heat to it, as to make it emit a yellowish white light. The tallow now liquefied, as fast as it boils away at the top of the wick, is, by the capillary attraction of the same wick, drawn up to supply the place of what is consumed by the cotton. The congeries of capillary tubes, which form the wick, is black, because it is converted into coal; a circumstance common to it with all other vegetable and animal substances, when part of the carbon and hydrogen which enter into their composition having been acted on by combustion, the remainder and other fixed parts are by any means whatever covered and defended from the action of the air. In this case, the burning substance owes its protection to the surrounding flame. For when the wick, by the continual wasting of the tallow, becomes too long to support itself in a perpendicular situation, the top of it projects out of the cone formed by the flame, and thus being exposed to the action of the air, is ignited, loses its blackness, and is converted into ashes; but that part of the combustible which is successively rendered volatile by the heat of the flame is not all burnt, but part of it escapes in the form of smoke through the middle of the flame, because that part cannot come in contact with the oxygen of the surrounding atmosphere; hence it follows, that with a large wick and a large flame, this waste of combustible matter is proportionately much greater than with a small wick and a small flame. In fact, when the wick is not greater than a single thread of cotton, the flame, though very small, is, however, peculiarly bright, and free from smoke; whereas in lamps, with very large wicks, such as are often suspended before butchers’ shops, or with those of the lamp-lighters, the smoke is very offensive, and in great measure eclipses the light of the flame.
A candle differs from a lamp in one very essential circumstance; viz. that the oil or tallow is liquefied, only as it comes into the vicinity of the combustion; and this fluid is retained in the hollow of the part, which is still concrete, and forms a kind of cup. The wick, therefore, should not, on this account, be too thin, because if this were the case, it would not carry off the material as fast as it becomes fused; and the consequence would be, that it would gutter or run down the sides of the candle: and as this inconvenience arises from the fusibility of the tallow it is plain that a more fusible candle will require a larger wick; or that the wick of a wax candle may be made thinner than that of one of tallow. The flame of a tallow candle will of course be yellow, smoky, and obscure, except for a short time after snuffing. When a candle with a thick wick is first lighted, and the wick snuffed short, the flame is perfect and luminous, unless its diameter be very great; in which last case, there is an opake part in the middle, where the combustion is impeded for want of air. As the wick becomes longer, the interval between its upper extremity and the apex of the flame is diminished; and consequently the tallow which issues from that extremity, having a less space of ignition to pass through, is less completely burned, and passes off partly in smoke. This evil increases, until at length the upper extremity of the wick projects beyond the flame and forms a support for an accumulation of soot which is afforded by the imperfect combustion, and which retains its figure, until, by the descent of the flame, the external air can have access to the upper extremity; but in this case, the requisite combustion which might snuff it, is not effected; for the portion of tallow emitted by the long wick is not only too large to be perfectly burned, but also carries off much of the heat of the flame, while it assumes the elastic state. By this diminished combustion, and increased afflux of half decomposed oil, a portion of coal or soot is deposited on the upper part of the wick, which gradually accumulates, and at length assumes the appearance of a fungus. The candle then does not give more than one-tenth of the light which the due combustion of its materials would produce; and, on this account, tallow candles require continual snuffing. But if we direct our attention to a wax candle, we find that as its wick lengthens, the light indeed becomes less. The wick, however, being thin and flexible, does not long occupy its place in the centre of the flame; neither does it, even in that situation, enlarge