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Proceedings of the Royal Society.

[Feb. 1, bits; with an introductory Account of purpose of investigating the causes of these the Telescopic Apparatus that has been accidents, and of searching for means of preused on this occasion, and a final Expo- venting them. In consequence of an invisition of some calculated Particulars de tation from the Rev. Dr. Gray, one of the duced from the Observations. By Wil- most active members of this committee, I liam Herschel, LL.D.

was induced to turn my attention to the sub. An Account of some Experiments jecit. I went to the north of England, and with a large Voltaic Battery. By J. G. visited some of the principal collieries in the Children, esq.

neighbourhood of Newcastle, for the purpose

of ascertaining the condition of the workings, On the Dispersive Power of the At- and the state of their ventilation. I found mosphere, and its Effect on Astronomi- the greatest desire to assist my inquiries in cal Observations. By Stephen Lee. the gentlemen acquainted with the northern

Deterinination of the North Polar collieries, as well as in the inspectors or Distances, and proper Motion of Thirty viewers of the mines : and I have particular Fixed Stars. By John Pond, esq. astro- obligations on this point to the Rev. Dr. nomer royal.

Gray, Cuthbert Ellison, esq. M. P., the Rev. An Essay towards the Calculus of John Hodgson, Mr. Buddle, and Mr. Dunn. Functions. By C. Babbage, esq.

Dr. Fenwick, Dr.Clanny, and Mr. Fenwick, Some additional Experiments and Ob- likewise kindly offered me their assistance. servations on the Relation which sub

From the information which I collected sists between the Nervous and Sanguife- on the spot, increased by the perusal of a rous Systems. By A. P. Wilson Philip. mines, I was convinced that, as far as venciAt the anniversary meeting of this dern science had been fully employed ; and

lation was concerned, the resources of moSociety on the 30th of November, the that a mode of preventing accidents was President and Council adjudged the gold orly to be sought for in a method of lightmedal given by Sir Godfrey Copley, to ing the mines free from danger, and which, Dr. David BREWSTER, for bis experi- by indicating the state of the air in the part ments and discoveries on light and heat of the mine where inflammable air was discontained in his papers in the Philoso- engaged, so as to render the atmosphere exphical Transactions.

plosive, should oblige the miners to retire The destructive accidents from the till the workings were properly cleared. explosion of inflammable gases iņ col An account of an ingenious apparatus for lieries, which we, in commun with all burning a candle, supplied with a mospheri. the friends of humanity, have lately had cal air by a bellows through water, has been such frequenti ccasion to deplore, have published in the Philosophical Transactions, recently induced several distinguished by Dr. Clanny; but I believe this apparatus scientific men to turn their attention to

has not yet been used in any of the col

lieries. the discovery of a method of lighting

The common means employed for lightthose subterranean recesses without endangering the lives of the workmen. apprehended from the fire-damp, is by a

ing those parts of the mine where danger is Various contrivances for this purpose steel wheel, which being made to revolve in have been devised, but none has been contact with fint, affords a succession of found to answer the end desired so com- sparks : but this apparatus always requires a pletely as the lamp invented by the illus- person to work it; and, though much less trious Sir HUMPHRY Davy, whose paper liable to explode the fire-damp than a comon this subject, read before the Royal mon candie, yet it is said to be not entirely Society on the 9th November, appears free from danger. of such importance to all persons em

Mr. Buddle having obligingly shown to ployed or interested in mines, that we me the degree of light required for working shall give it entire.

the collieries, I made several experiments,

with the hope of producing such a degree of On the Fire-damp of Coal-Mines, and light, without active is flammation; I tried

on Methods of Lighting the Mines so Kunckel's,Canton's, and Baldwin's phosphoes to prevent its Explosion. By Sir rus, and likewise the electrical lighi in close H. Davy.

vessels, but without success; and even had The accidents arising from the explosion these degrees of light been sufficient, the of the fire-damp or inflammable gas of coal- processes for obtaining them, I found, would mines, mixed with atmospherical air, are an be too complicated and difficult for the nually becoming more frequent and more miners. destructive in the collieries in the north of The fire-damp has been shown by Dr. England.

Henry, in a very ingenious paper published A committee has been for some time in the nineteenth volume of Nicholson's formed at Sunderland, for the benevolent Journal, to be light carburetted hydrogen gas,

1816.)

Sir H. Davy on preventing Explosions in Coal Mines.

39

and Dr. Thomson has made some experi- mines are, however, what are called blowments upon it; but the degree of its combus ers, or fissures in the broken strata, near tibility, as compared with that of other in- dykes, from which currents of fire-damp issue flammable gases, has not, I believe, been in considerable quantity, and sometimes for examined, nor have many different speci- a long course of years. When old workmens of it been analyzed; and it appeared ings are broken into, likewise, they are often to me, that some minute chemical experi- found filled with fire-damp; and the deeper ments on its properties ought to be the pre the mine the more common in general is liminary steps to inquiries respecting me this substance. thods of presenting its explosion. I there I have analyzed several specimens of the fore procured various specimens of the fire- fire-damp in the laboratory of the Royal Indamp in its purest state, and made a number stitution; the pure inflammable part was the · of experiments upon it. And in examining same in all of them, but it was sometimes its relacions to combustion, I was so fortu- mixed with small quantities of atmospherical nate as to discover some properties belonging air, and in some instances with azote and to it, which appear to lead to very simple carbonic acid. methods of lighting the mines, without dan Of six specimens collected by Mr. Dann ger to the miners, and which, I hope, will from a blower in the Hepburn colliery, by supply the desiderarum so long anxiously re emptying bottles of water close to it, the quired by humanity.

purest contained one-fifteenth only of atmos. The fire-damp is produced in small quán- pherical air, with no other contamination, tities in coal-mines, during the common and the most impure contained five-twelfths process of working,

of atmospherical air; so that this air was The Rev.Mr.Hodgson informed me,that on probably derived from the circumambient pounding some common Newcastle coal fresh air of the mine. The weight of the purest from the mine in a cask furnished with a small specimen was for 100 cubical inches 19.5 aperture, the gas from the aperture was in. grains. Hammable. And on breaking some large One measure of it required for its complete lumps of coal under water, I ascertained that combustion by the electric spark nearly two they gave off inflammable gas.* Gas is like measures of oxygen, and they formed nearly wise disengaged from bituminous-schist, one measure of carbonic acid. whca it is worked.

Sulphur heated strongly, and repeatedly The great sources of the fire-damp in sublimed in a portion of it freed from oxy

. This is probably owing to the coal strata gen by phosphorus, produced a considerbaving been formed under a pressure greater able enlargement of its volume, sulphuretted than that of the atmosphere, so that they hydrogen was formed, and charcoal precipigive off elastic Huid when they are exposed tated ; and it was found that the volume of to the free atmosphere : and probably coals the sulphuretted hydrogen produced, when it containing animal remains evolve not only

was absorbed by solution of potassa, was exthe fire-damp, but likewise azote and carbo- actly double that of the fire-damp decomnic acid, as in the instance of the gas sent by posed. Dr. Clanny

It did not act upon chlorine in the cold ; In the Apennincs, near Pietra Mala, I ex

but, when an electric spark was passed amined a fire produced by gaseous matter, through a mixture of one part of it with two constantly disengaged from a schist stratum :

of chlorine, there was an explosion, with a and from the results of the combustion, I diminution to less than one-fourth, and have no doubt that it was pure fire-damp. much charcoal was deposited. Mr, M. Faraday, who accompanied me, and

The analysis of specimens of gas sent to assisted me in my chemical experiments, in my friend John George Children, esq. by my journey, collected some gas from a ca Dr. Cianny, afforded me similar results ; but vity in the earth, about a mile from Pietra they contained variable quantities of carbonic Mala, then filled with water, and which, acid gas and azote. from the yuantity of gas disengaged, is called

Different specimens of these gases were Aqua Buja. I analysed it in the Grand tried by the test of exposure to chlorine both Duke's laboratory at Florence, and found in darkness and light : they exbibited no that it was pure light hydro-carbonate, re- marks of the presence of olefiant gas or hyquiring two volumes of oxygen for its com- drogen; and the residuum produced by debustion, and producing a volume of carbonic tonation with chlorine showed them to be

free from carbonic oxide. It is very probable that these gases are dis It is evident, then, that the opinion formed engaged from coal strata beneath the surface, by other chemists respecting the fire damp is o from bituminous schist above coal; and perfectly correct; and that it is the same at some future period new sources of riches substance as the inflammable gas of marshes, may be opened to Tuscany from this invalu • Sir James Lowther found a unitorm curable mineral treasure, the use of which, in rent produced in one of his mines for two this country, has supplied such extraordinary years and nine months. Phil, Trans, rok. resources to industry.

xxxviii, p, 112,

aoid gas.

40

Sir H. Davy on preventing Explosions in Coal Mincs. (Feb. I,

no

the exact chemical nature of which was first both charcoal and iron heated to dull redness. demonstrated by Mr. Dalton; and that it Gaseous oxide of carbon, which explodes consists, according to my view of definite whenmixed with 2 parts of air, is likewise proportions, of 4 proportions of hydrogen in inflammable by red-hot iron and charcoal. weight 4, and one proportion of charcoal in And hydrogen, which explodes when mixed weight 11.5.

with three-sevenths of its volume of air, I made several experiments on the com takes fire at the lowest visible heat of iron bustibility and explosive nature of the fire- and charcoal; and the case is the samc with damp. When 1 part of fire-damp, was mix- sulphurerted hydrogen. ed with 1 of air, they burnt by the approach I endeavoured to ascertain the degree of of a lighted taper, but did not explode; 2 of expansion of mixtures of fire-damp and air air and 3 of air 10 i of gas produced similar during their explosion, and likewise their results. When 4 of air and 1 of gas were ex power of communicating Haine through posed to a lighted candle, the mixture being apertures to other explosive mixtures. in the quantity of 6 or 7 cubical inches in a I found that when 6 of wir and i of firenarrow-necked botile, a flame descended damp were exploded over water by a strong through the mixture, but there was electrical spark, the explosion was not very noise : 1 part of gas, inflamed with 6 parts of strong, and, at the moment of the greatest air in a similai bottle, produced a slight expansion, the volume of the gas did not apwhistling sound : 1 part of gas with 8 parts pear to be increased more than one balf. of air rather a louder sound : 1 part with 10, In exploding a mixture of i part of gas 11, 12, 13, and 14 parts, still infiamed, but from the distillation of coal, and 8 parts of the violence of combustion diminished. In air in a tube of a quarter of an inch in diai part of gas and 15 parts of air, the candle meter and a foot long, more than a second burst without explosion with a greatly en was required before the flame reached from largeu Hame: and the effect of enlarging the one end of the tube to the other; and I could flame, but in a gradually diminishing ratio, not make any mixture explode in a glass tube was produced as far as 30 parts of air to i of one-seventh of an inch in diameter: and this gas.

gas was more inflammable than the fireThe mixture which seemed to possess the damp, as it consisted of carburetted hydrogen greatest explosive power, was that of 7 or 8 gas mixed with some olefiant gas. parts of air io 1 of gas; but the report pro In exploding mixtures of fire-damp and duced by 50 cubical inches of this mixture air in a jar cornected with the atmosphere was less than that produced by one-tenth of by an aperture of half an inch, and, conthe quantity of a mixture of 2 parts of atmos nected with a bladder by a stopcock, having pherical air and 1 of hydrogen.

an aperture of about one-sixth of an inch, It was very important to ascertain the de. I found that the fame passed into the atgree of heat required to explode the fire- mosphere, but did not communicate through damp mixed with its proper proportion of the stopcock, so as to inflame the mixture air.

in the bladder : and on comparing the power I found that a common electrical spark of tubes of metal and those of glass, it ap. would not explode 5 parts of air and 1 of peared that the flame passed more readily fire-damp, though it exploded 6 parts of air through glass tubes of the saine diameter; and 1 of damp: but very strong sparks from and that explosions were stopped by metallic the discharge of a Leyden jar seemed to have tubes of one-fifth of an inch, t when they the same power of exploding different mix were 14 inch long; and this phænonienon tures of the gas as the flame of the taper. probably depends upon the beat lost during Well-burned charcoal, ignited to the strong. the explosion in contact with so great a est red heat, did not explode any mixture of cooling surface, which brings the temperaair and of the fire-damp; and a fire made of ture of the first portions exploded below that well-burned charcoal, i. e. charcoal that required for the firing of the other portions. burned without fame, was blown up to Metal is a better conductor of heat than whiteness by an explosive mixture contain- glass : and it has been already shown that ing the fire-damp, without producing its in- the fire-damp requires a very strong heat for flammation. An iron rod at the highest de- its inflammation. gree of red heat, and at the common degree Mixture of the gas with air I found, likeof white heat, di Inot inflame explosive mix. wise, would not explode in metallic canals tures of the fire-damp; but, when in brilliant combustion, it produced the effect. * Since these experiments were made,

The fiame of gasevus oxide of carbon as Dr. Wollaston has informed me, that he and well as of olefiant gas exploded the mixtures Mr. Teunant had observed some time ago, of the fire-danip.

that mixtures ofine gas from the distillation In r. spect if combustibility, then, the of coal and! 111 would not explode in very fire-d :-p diffe is most materially from the small tubes. other common infiammable gases. Olefiant + I do not give this result as perfectly ex. gas, which I bave found explodes mixed in act, as the bore of the metallic tube bad not the same proportion with air, is fired by the same polish as that of the tube of glass,

1816.] Sir H. Davy on preventing Explosions in Coal Mines.

-41 or troughs, when their diameter was less ing of a flame in atmospheres containing than one seventh of an inch, and their fire-damp. I inclosed a taper in a litic close depth considerable in proportion to their dia- lantern, having a small aperture bow, and meter ; nis could explosions be made to a larger one above, of such size that the tapass through such canals.

per burned with a flame a little below its na. Explosion, likewise, I found would not tural size. I placed this lantem, the taper pass thrugi very fine wire sieves or wire being lighted, on a stand under a large glass gauze.

receiver standing in water having a curved I mixed azote and carbonic acid in differ. cube containing a little water adapted to its ent quanuitis with explosive mixtures of top to confine the air, and which was of such fire damp, and I found that even in very a capacity as to enable the candle to burn small proportions they diminished the velo for some minutes; I then rapidly threw a city of the inflammation. zote, when quantity of fire-damp into the receiver, from m xe' in the pr portion of i to o of an ex. a bladder, so as in make the atmosphere in plo-ive mixture, containing 12 of air and it explosive. As the fire-damp mixed with 1 of fire-damp, deprived it of its power of the air, the flame of the taper gradually enexplosion; when i part of azote, was mixed Targed, till it half filled the lantern ; it then wib 7 of an explosive mixture, only a fee rapidly diminished, and was suddenly extinble blue flame slowly passed through the guished without the slightest explosion. I mixture.

examined the air of the receiver, after the One part of carbonic acid 10 7 of an explo. experiment, and found it highly explosive. sive mixture deprived it of the power of ex I tried similar experiments, throwing in pk 1:19; o that its effects are more remark mixtures of air and fire-damp, some conable than those of azote ; probably, in con taining the maximum and others the minisequince of its greater capacity for heat, and mum of fire-damp necessary for explosion probably, likewise, of a higher conducting and always with the same satisfactory results. power connerred with its greater density. The flame considerably increased, and was

The consideration of these various facts soon extinguished. led me to adopt a form of a lamp, in which I introduced a lighted lantern to which the fame by being supplied with only a air was supplied by two glass tubes onelimiteri quantity of air, should produce such tenth of an inch in diameter, and half an a quantity of azote and carbonic acid as to inch long, into a large jar containing an exprevenne e le explusion of the fire-damp, and plosive mixture of i part of fire-damp and which, by the nature of its apertures for 10 parts of air ; the taper burned at first with giving artmittance and axit to the air, should a feeble light, the flame soon became enbe readered incapable of communicating any larged, and was then extinguished. I reexplosion to the external air,

peated these experiments several times, and If in a close, lantern, supplied with a with a perfect constancy of result, small aperture below and another above, a It is evident, then, that to prevent explolighted lamp, having a very small wick, be siun in coal-mines, it is only necessary to placed, the natural fiame gradually dini use air-tight lantoms, supplied with air from nishes, ill it arrives at a point at which the tubes or canals of small diameter, or from supply of air is sufficient for the combus apertures covered with wire gauze placed tion of a certain small quantity of oil; if a below the flame, through which explosions lighted taper be in roduced into the lantern cannot be communicatèd, and having a through a small door in the side, which is chimney at the upper part, on a similar sysinstantly closed, both lights will burn for a tem for carrying off the soul air; and comfew seconds, and be extinguished together. mon lanterns may be easily adapted to the

A similar phænomenon occurs, if, in a purpose, by being made air-tight in the door close lantern, supplied with a quantity of air and sides, by being furnished with the chim. merely sufficient to support a certain flame, ney and the system of safety apertures bea mixture of fire-damp and air is gradually low and above. admitted : the first effect of the fire-damp is The principle being known, it is easy to to produce a larger flame round that of the adopt and multiply practical applications of lamp, and this fame, consuming the oxy.

it. gen which ought to be supplied to the fame The first safe-lantern that I had construct of the lamp, and the standard of the powered was made of tin-plate, and the light of the air to support farne being lowered by emitted through four glass plates in the the admixture of fire-amp and by its rare sides. The air was admitted round the botfaction, both the flame of the fire-damp and tom of the fame from a number of metallic that of the laper are extinguished together; tubes of one eighth of an inch in diameter, and as the air contained a certain quantity and an inch and a half long. The chininey of azole and carbonic acid before the admis was composed of two open cones, having a sion of the fire-damp, their effect, by mixing common base perforated with many small with it, is such as to prevent an explosion in apertures, and fastened to the top of the lanany part of the lantern.

tern, which was made right in a pneumatic I tried several experiments on the burn- rim containing a little oil; the upper and New MONTHLY MAG,-No, 25,

Vol. V.

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Sir H. Davy on preventing Explosions in Coal Mines. [Feb. 1,

lower apertures in the chimney were about hollow metallic cylinders of different diz. one-eighth of an inch : thc lamp, which was meters, and placed together so as to form fed with oil, gave a steady flame of about an cicular canals of the diameter of from oneinch high, and half an inch in diameter. twenty-fifth to one-fortieth of an inch, and When the lantern was slowly moved, the an inch and seven-tenths long, hy which air lamp continued to burn, but more feebly; is admitted in. much larger quantities than and when it was more rapidly moved, it by the small tubes. In this arrangement went out. To obviate this circumstance, I there is so free a circulation of air, that the surrounded the bottom of the lantern with a chimney likewise may be furnished with perforated rim; and this arrangement per- satety-canals. fectly answered the end proposed.

I have had lamps made for this kind of I had another chimney fitted to this lan- lantern which stand on the outside, and tern, furnished with a number of safety in which may be supplied with oil and cotton plates of the sixth of an inch in diameter, without any necessity of opening the lanand two inches long; but they diminished tern; and in this case the chimney is soldered considerably the size of the flame, and ren to the top, and the lamp is screwed into the dered it more liable to go out by motion; bottom, and the wick rises above the air and the following experiments appear to canals. show, that if the diameter of the upper ori- I have likewise had glass lamps with a fice of the chimney be not very large, it is single wick, and Argand lamps made on the scarcely possible that any explosion pro- same principle, the chimney being of glass, duced by the flame can reach it.

covered with a metallic top containing the I threw into the safe lantern with the com- safety-canals, and the air entering close to mon chimney, a mixtuse of 15 parts of air the flame through the circular canals. and i of fire-damp: the flame was imme. The third kind of sate lamp or lantern, diately greatly enlarged, and the flame of the and which is by far the most simple, is a wick seemed to be lost in the larger flame close lamp or lantern, into which the air is of the fire-damp. I placed a lighted taper admitted, and from which it passes, through above the orifice of the chimney: it was apertures covered with brass wire gauze of immediately extinguished, but without the One-two-hundredth of an inch in thickness, slightest previous increase of its flame, and the apertures of which should not be more even the wick instantly lost its fire by being than one-two-hundsedth of an inch; this plunged into the chimney.

stops explosions as well as long tubes or I introduced a lighted taper into a close canals, and yet admits of a free draught of vessel containing 15 parts of air and i of gas air. from the distillation of coal, suffered it to Having succeeded in the construction of burn out in the vessel, and then analysed safe-lanterns and lamps, equally portable the gas. After the carbonic acid was sepa- with common lanterns and lamps, which afrated, it appeared by the test of nitrous gas forded sufficient light, and which bore moto contain nearly one-third of its original tion perfectly well, I submitted them indiquantity of oxygen ; but detonation with a vidually to practical tests, by throwing into mixture of equal parts of hydrogen and them explosive atmospheres of fire-dampand • oxygen proved that it contained no sensible air. By the natural action of the flame quantity of carburetted hydrogen gas. drawing air through the air canals from the

It is evident, then, that when in the safe. explosive atmosphere, the light was unilanıcın the air gradually becomes contami- formly extinguished; and when an explonated with fire.damp, this fire damp will be sive mixture was forcibly pressed into the consumed in the body of the lantern ; and body of the lamp, the explosion was always that the air passing through the chimney stopped by the safety apertures, which may cannot contain any inflammable mixture. be said figuratively to act as a sort of chemi.

I made a direct experiment on this point. cul fire-sieves, in scparating flame from air. I gradually threw an explosive mixture of But I was not contented with these tuals. fire-damp and air into the safe lantern from aud I submitted the safety canals, tubes, and a bladder furnished with a tube which open- wire-gauze fire-sieves, to much more severe ed by a large aperture above the flame; the tests: I made them the mediuni of commuflame became enlarged, and by a rapid jet of nication between a large glass vessel filled gas I produced an explosion in the body of with the strongest explosive mixture of carthe lantern; there was not even a current buretted hydrogen and air, and a bladder of air through the safety tubes at the mo. two-thirds or one-half full of the same mixment, and the flame did not appear to reach ture, both insulated from the atmosphere. above the lower aperture of the chimney; By means of wires passing near the stop-cock and the explosion merely threw out froin it of the glass vessel, I fired the explosive mix a gust of foul air.

ture in it by the discharge of a Leyden jar, The second safety-lantern that I have had The bladder always expanded at the mo. made is upon the same principle as the first, ment the explosion was made ; a contracexcept that instead of tubes, safety.canals tion as rapidly took place ; and a lambent are used, which consist of close concentric flame played round the mouths of the safety

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