Chapter XI (1)

Collieries of the North of England.--Fire-damp.--The dreadful
explosion at Felling Colliery described.--Letters from the
Bishop of Bristol to the Author.--A Society is established
at Bishop-Wearmouth for preventing accidents in coal
mines.--Various projects for ensuring the miner's safety.--The
Reverend Dr. Gray, the present Bishop of Bristol, addresses
a letter to Sir H. Davy, and invites his attention to the
subject.--Sir H. Davy's reply.--Farther correspondence
upon the possibility of devising means of security.--Sir
H. Davy proposes four different kinds of lamp for the
purpose.--The Safe-lamp--The Blowing-lamp--The Piston-lamp--The
Charcoal-lamp.--His investigation of the properties of
fire-damp leads to the discovery of a new principle of
safety.--His views developed in a paper read before the
Royal Society on the 9th of November 1815.--The first
Safety-lamp.--Safety-tubes superseded by Safety-canals.--Flame
Sieves.--Wire-gauze lamp.--The phenomenon of slow Combustion,
and its curious application.--The invention of the Safety-lamp
claimed by a Mr. Stephenson.--A deputation of Coal-owners
wait upon Sir H. Davy, in order to express to him the thanks
of the Proprietors for his discovery.--Mr. Buddle announces
to Dr. Gray (now Bishop of Bristol) the intention of the Coal
trade to present him with a service of plate.--The Resolutions
are opposed, and the claims of Stephenson urged, by Mr. W.
Brandling.--A dinner is given to Sir Humphry, at which the
plate is presented to him.--The President and Council of
the Royal Society protest against the claims still urged by
Mr. Stephenson's friends.--Mr. Buddle's letter in answer
to several queries submitted to him by the Author.--Davy's
Researches on Flame.--He receives from the Royal Society the
Rumford Medals.--Is created a Baronet.--Some observations on
the apathy of the State in rewarding scientific merit.--The
Geological Society of Cornwall receives the patronage and
support of Sir Humphry.

A few months after the return of Sir Humphry Davy to England, his talents were put in requisition to discover some remedy for an evil which had hitherto defied the skill of the best practical engineers and mechanics of the kingdom, and which continued to scatter misery and death amidst an important and laborious class of our countrymen.

To collect and publish a detailed account of the numerous and awful accidents which have occurred within the last few years, from the explosion of inflammable air, or _fire-damp_, in the coal mines of the North of England, would present a picture of the most appalling nature. It appears from a statement by Dr. Clanny, in the year 1813,[22] that, in the space of seven years, upwards of three hundred pitmen had been suddenly deprived of their lives, besides a considerable number who had been severely wounded; and that more than three hundred women and children had been left in a state of the greatest distress and poverty; since which period the mines have increased in depth, and until the happy discovery of Davy, the accidents continued to increase in number.

[22] Phil. Transact. 1813.

It may well be asked how it can possibly have happened that, in a country so enlightened by science and so distinguished for humanity, an evil of such fearful magnitude, and of such frequent recurrence, should for so long a period have excited but little sympathy, beyond the immediate scene of the catastrophe. It would seem that a certain degree of doubt and mystery, or novelty, is essentially necessary to create that species of dramatic interest by which the passions are excited through the medium of the imagination: it is thus that the philanthropist penetrates unknown regions, in search of objects for his compassion, while he passes unheeded the miserable groups who crowd his threshold; it is thus that the statesman pleads the injuries of the Negro with an eloquence that shakes the thrones of kings, while he bestows not a thought upon the intrepid labourers in his own country, who for a miserable pittance pass their days in the caverns of the earth, to procure for him the means of defying the severity of winter, and of chasing away the gloom of his climate by an artificial sunshine.

That the benefits conferred upon mankind by the labours of Sir H. Davy may be properly appreciated, it is necessary to describe the magnitude of the evil which his genius has removed, as well as the numerous difficulties which opposed his efforts and counteracted his designs.

The great coal field,[23] the scene of those awful accidents which will be hereafter described, extends over a considerable part of the counties of Northumberland and Durham. The whole surface has been calculated at a hundred and eighty square miles, and the number of different beds of coal has been stated to exceed forty; many of which, however, are insignificant in point of dimensions. The two most important are about six feet in thickness, and are distinguished by the names of _High main_, and _Low main_, the former being about sixty fathoms above the latter.

[23] Dr. Thomson has calculated that the quantity of coal
exported yearly from this formation exceeds two millions of
chaldrons; and he thinks it may be fairly stated, in round
numbers, that, at the present rate of waste, it will continue
to supply coal for a thousand years! Mr. Phillips, however, is
inclined to deduct a century or two from this calculation.

From this statement, some idea may be formed of the great extent of the excavations, and of the consequent difficulty of successfully ventilating the mines. In some collieries, they are continued for many miles, forming numerous windings and turnings, along which the pitmen have frequently to walk for forty or fifty minutes, before they arrive at the workings; during which time, as well as when at work, they have no direct communication with the surface of the earth. The most ingenious machinery, however, has been contrived for conducting pure air through every part of the mine, and for even ventilating the old excavations, which are technically called _Wastes_; and unless some obstruction occur, the plan[24] so far answers, as to furnish wholesome air to the pitmen, and to diminish, although, for reasons to be hereafter stated, it can never wholly prevent, the dangers of _fire-damp_; the nature of which it will be necessary to consider.

[24] In all large collieries, the air is accelerated through
the workings by placing furnaces, sometimes at the bottom, and
sometimes at the top of the up-cast shaft; in aid of which, at
Wall's-end Colliery, a powerful air-pump worked by a steam-engine
is employed to quicken the draft: this alone draws out of the
mines a thousand hogsheads of air every minute. Stoppings and
trapdoors are also interposed in various parts of the workings,
in order to give a direction to the draft.

The coal appears to part with a portion of _carburetted hydrogen_, when newly exposed to the atmosphere; a fact which explains the well-known circumstance of the coal being more inflammable when fresh from the pit, than after long exposure to the air. We are informed by the Rev. Mr. Hodgson, that, on pounding some common Newcastle coal fresh from the mine, in a cask furnished with a small aperture, he found the gas which issued from it to be inflammable; and Davy, on breaking some lumps of coal under water, also ascertained that they gave off inflammable gas. The supposition that the coal strata have been formed under a pressure greater than that of the atmosphere, may furnish a clue to the comprehension of this phenomenon.

On some occasions the pitmen have opened with their picks crevices, or fissures, in the coal or shale, which have emitted as much as seven hundred hogsheads of _fire-damp_ in a minute. These _Blowers_, as they are technically termed, have been known to continue in a state of activity for many months, or even years together;[25] a phenomenon which clearly shows that the carburetted hydrogen must have existed in the cavities of the strata in a very highly compressed, if not actually in a liquid state, and which, on the diminution of pressure, has resumed its elastic form.

[25] Sir James Lowther found a uniform current of this
description produced in one of his mines for the space of two
years and nine months. Phil. Trans, vol. 38. p. 112.

All the sources of carburetted hydrogen would appear to unite in the deep and valuable collieries situated between the great North road and the sea. Their air courses are thirty or forty miles in length; and here, as might be expected, the most tremendous explosions have happened. Old workings, likewise, upon being broken into, have not unfrequently been found filled with this gas, and which, by mingling itself with the common air, has converted the whole atmosphere of the mine into a magazine of _fire-damp_.

On the approach of a candle, it is in an instant kindled: the expanding fluid drives before it a roaring whirlwind of flaming air, which tears up every thing in its progress, scorching some of the miners to a cinder, and burying others under enormous ruins shaken from the roof; when thundering to the shafts, it converts the mine, as it were, into an enormous piece of artillery, and wastes its fury in a discharge of thick clouds of coal-dust, stones, and timber, together with the limbs and mangled bodies of men and horses.

But this first, though apparently the most appalling, is not the most destructive effect of these subterraneous combustions. All the _stoppings_ and trapdoors of the mine being blown down by the violence of the concussion, and the atmospheric current entirely excluded from the workings, such of the miners as may have survived the discharge are doomed to the more painful and lingering death of suffocation from the _after-damp_, or _stythe_, as it is termed, which immediately results from the combustion, and occupies the vacuum necessarily produced by it.

As the phenomena accompanying these explosions are always of the same description, to relate the numerous recorded histories of such accidents would be only to multiply pictures of death and human suffering, without an adequate object: it is, however, essential to the just comprehension of the subject, that the reader should receive at least one well-authenticated account, in all its terrific details; and I have accordingly selected that which was originally drawn up with much accuracy and feeling by the Reverend John Hodgson, and which is prefixed to the funeral sermon preached on the occasion, and subsequently published by that gentleman.

The accident occurred at Felling Colliery, near Sunderland, on the 25th of May, in the year 1812. This mine was considered by the workmen as a model of perfection, both with regard to the purity of its air, and the arrangements of its machinery. The concern was in the highest degree prosperous; and no accident, except a trifling explosion which slightly scorched two or three pitmen, had ever occurred.

Two _shifts_, or sets of men, were constantly employed, the first of which entered the mine at four, and were relieved at their working posts by the next set at eleven o'clock in the morning; but such was the confidence of the pitmen in the safety of this mine, that the second shift of men were often at their posts before the first set had left them; and such happened to be the case on the following unhappy occasion.

About half past eleven, on the morning of the 25th of May, the neighbouring villages were alarmed by a tremendous explosion. The subterraneous fire broke forth with two heavy discharges from the shaft called the '_John Pit_,' which was one hundred and two fathoms deep, and were almost immediately followed by one from that termed the '_William pit_,' A slight trembling, as if from an earthquake, was felt for about half a mile around the workings; and the noise of the explosion, though dull, was heard to the distance of three or four miles, and greatly resembled an unsteady fire of infantry.

Immense quantities of dust and small coal accompanied these blasts, and rose high into the air, in the form of an inverted cone. The heaviest part of the ejected matter, such as masses of timber, and fragments of coal, fell near the pit, but the dust, borne away by a strong west wind, fell in a continued shower to the distance of a mile and a half; and in the village of Heworth, it caused a gloom, like that of early twilight, and so covered the roads that the footsteps of passengers were strongly imprinted on them.

As soon as the explosion had been heard, the wives and children of the pitmen rushed to the working pit. Wildness and terror were pictured in every countenance. The crowd thickened from every side, and in a very short period several hundred persons had collected together; and the air resounded with exclamations of despair for the fate of husbands, parents, and children.

The machinery having been rendered useless by the eruption, the rope of the _gin_ was sent down the shaft with all possible expedition. In the absence of horses, a number of men, who seemed to acquire strength as the necessity for it increased, applied their shoulders to the _starts_, or shafts of the gin, and worked it with astonishing expedition.

By twelve o'clock, thirty-two persons, all that survived this dreadful catastrophe, had been brought to daylight, but of these three boys lived only a few hours. The dead bodies of two boys, miserably scorched and shattered, were also brought up at the same time. Twenty-nine persons, then, were all who were left to relate what they had observed of the appearances and effect of the explosion. One hundred and twenty-one were in the mine when it happened, eighty-seven of whom remained in the workings. Eight persons had fortunately come up a short time before the accident.

Those who had their friends restored, hastened with them from the scene of destruction, and for a while appeared to suffer as much from an excess of joy, as they had a short time before from the depth of despair; while those who were yet in the agony of suspense, filled the air with shrieks and howlings, and ran about wringing their hands and throwing their bodies into the most frantic and extravagant gestures.

As not one of the pitmen had escaped from the mine by the only avenue open to them, the apprehension for their safety momentarily increased, and at a quarter after twelve o'clock, nine persons descended the John pit, with the faint hope that some might still survive.

As the fire-damp would have been instantly ignited by candles, they lighted their way by _steel-mills_;[26] and knowing that a great number of the miners must have been at the crane when the explosion happened, they at once attempted to reach that spot: their progress, however, was very soon intercepted by the prevalence of _choak damp_, and the sparks from their steel-mill fell into it like dark drops of blood: deprived therefore of light, and nearly suffocated by the noxious atmosphere, they retraced their steps towards the shaft, but they were shortly stopped by a thick smoke which stood like a wall before them. Here their steel-mills became entirely useless, and the chance of their ever finding any of their companions alive entirely hopeless; to which should also be added the horror arising from the conviction of the mine being on fire, and the probability of a second explosion occurring at the next moment, and of their being buried in the ruins it would occasion.

[26] Steel-mills are small machines, which give light by turning
a cylinder of steel against a piece of flint. Sir James Lowther
had observed early in the last century, that the fire-damp in its
usual form was not inflammable by sparks from flint and steel;
and it appears that a person in his employment invented the
machine in question.

At two o'clock, five of the intrepid persons who had thus nobly volunteered their assistance, ascended; two were still in the shaft, and the other two remained below, when a second explosion, much less severe, however, than the first, excited amongst the relatives of those entombed in the mine still more frightful expressions of grief and despair. The persons in the shaft experienced but little inconvenience from this fresh eruption, while those below, on hearing the distant growlings, immediately threw themselves flat on their faces, and in this posture, by keeping a firm hold on a strong wooden prop, they felt no other annoyance from the blast than that of having their bodies tossed in various directions, in the manner that a buoy is heaved by the waves of the sea. As soon as the atmospheric current returned down the shaft, they were safely drawn to the light.

As each came up, he was surrounded by a group of anxious enquirers; but not a ray of hope could be elicited; and the second explosion so strongly corroborated their account of the impure state of the mine, that their assertions for the present seemed to obtain credit. This impression, however, was but of short duration,--hope still lingered; they recollected that persons had survived similar accidents, and that, upon opening the mine, they had been found alive after considerable intervals. Three miners, for instance, had been shut up for forty days in a pit near Byker, and during the whole of that period had subsisted on candles and horse-beans. Persons too were not wanting to agitate the minds of the relatives with disbelief in the report of the pitmen who had lately descended to explore the mine. It was suggested to them, that want of courage, or bribery, might have induced them to magnify the danger, and to represent the impossibility of reaching the bodies of the unfortunate sufferers. By this species of wicked industry, the grief of the neighbourhood began to change its gloomy, for an irritable aspect. The proposition to exclude the atmospheric air from the mine, in order to extinguish the fire, was received with the cries of _Murder!_--and with the determination to oppose such a proceeding by violence.

Many of the widows lingered about the mouth of the pit during the whole of the night with the hope of hearing the cries of a husband or a son.

On Tuesday the 26th, that natural propensity in the human mind to derive gratification from spectacles of horror, was exemplified in a very striking manner. An immense crowd of colliers from various parts, but more especially from the banks of the river Wear, assembled around the pit, and were clamorous in their reproaches of the persons concerned in the management of the mine, accusing them of want of perseverance in their attempts to rescue the unhappy sufferers. Every one had some successful adventure to relate; all were liberal in their professions of readiness to give assistance; but not one was found hardy enough to enter the jaws of the burning cavern.

The leaders of this outcry, however, who had been led into error by an impulse which did honour to their hearts, were soon brought to listen with patience to a relation of all the circumstances of the explosion, and of the reasons for concluding that the mine was then actually on fire, and the persons enclosed in it beyond the hope of recovery. They very candidly allowed, after this explanation, the impracticability of any attempt to reach the bodies of the sufferers, until the fire was extinguished; and they accordingly urged the propriety of excluding from the mine the access of air, as the only means of accomplishing the object. At the same time, the proprietors gave the strongest assurances to the multitude, that if any project could be devised for the recovery of their friends, no cost or labour should be spared in executing it; that, if any person could be found willing to enter the mine, every facility and assistance should be afforded him; but, as they were assured by the most eminent Viewers that the workings were inaccessible, they would not hold out any reward for the attempt,--they would not be accessary to the death of any one, either by persuasion or bribery.

At the clamorous solicitation, however, of the populace, two persons again descended the shaft, and very nearly lost their lives in the attempt. The report of these last adventurers, in a great measure, convinced the people of the impossibility of their friends' survival in so deadly an atmosphere, and reconciled them to the plan of excluding the air. The operation was accordingly commenced, and it proceeded without interruption; but from various accidents, more than a month elapsed before the mine was in a state to admit of examination; and during this interval, numerous were the idle tales which had been circulated throughout the country. Several of the sufferers, it was said, had found their way to the shafts, and been recovered. Their number even had been circumstantially told--how they had subsisted on candles, oats, and beans, and how they had heard the different persons who explored the mine in the hope of rescuing them.

Some conjuror too, it was said, had set his spells and divinations to work, and had penetrated all the secrets of the mine. He had discovered one famishing group receiving drops of water from the roof, another eating their shoes and clothes, and many other similar pictures of horror. These inventions were carefully related to the widows, and they produced the effect of daily harrowing up afresh their sorrows; indeed, it seemed the chief employment of some to indulge in a kind of insane sport with their own and their neighbours' calamity.

The morning of Wednesday the 8th of July having been appointed for exploring the workings, the distress of the neighbourhood was again renewed at an early hour: a great concourse of people assembled; some, out of curiosity, to witness the commencement of an undertaking full of sadness and danger,--some to excite the revenge, or to aggravate the sorrows, of the relatives by calumnies and reproaches, for the sole purpose of mischief; but the greater part came with broken hearts and streaming eyes, in expectation of seeing the mangled corpse of a father, brother, husband, or son.

The _shifts_ of men employed in this doleful and unwholesome work were generally about eight in number. They were four hours in, and eight hours out of the mine; so that each individual wrought two shifts every twenty-four hours.

When the first shift of men came up, a message was dispatched for a number of coffins to be in readiness at the mouth of the pit. Ninety-two had been prepared, and they had to pass by the village of Low Felling, in their way to the mine. As soon as a cart-load of them was seen, the howling of the women, who, hitherto secluded in their dwellings, had now begun to assemble about their doors, came on the breeze in slow fitful gusts, which presaged a scene of the greatest distress and confusion.

The bodies were found under various circumstances: one miner, from his position, must have been sleeping when the explosion happened, and had never opened his eyes. In one spot were found twenty-one bodies in ghastly confusion,--some like mummies, scorched as dry as if they had been baked; one wanted its head, another an arm--the scene was most terrific: the power of the fire was visible upon all, but its effects were very various; while some were almost torn to pieces, there were others who appeared as if they had sunk down overpowered by sleep.

Every family had made arrangements for receiving the dead bodies of their kindred; but Dr. Ramsay having given his opinion, that such a proceeding might spread a putrid fever through the neighbourhood, and the first body when exposed to observation having presented a most horrid and corrupt appearance, the people very properly consented to have each body interred as soon as it was discovered, on condition that the hearse, in its way to the chapel-yard, should pass by the door of the deceased.

From the 8th of July to the 19th of September, the heart-rending scene of mothers and widows examining the putrid bodies of their sons and husbands, for marks by which to identify them, was daily renewed; but very few of them were recognised by any personal mark--they were too much mangled and scorched to retain any of their features: their clothes, tobacco-boxes, and shoes, were therefore the only indications by which they could be identified.

The total loss from this terrible accident was ninety-two pitmen; while forty widows, sixty girls, and twenty-six boys, comprising in all one hundred and twenty six persons, were thrown upon the benevolence of the public.

It was impossible that an event of such awful magnitude should not have deeply affected every humane person resident in the district. Nothing, in short, could exceed the anxiety which was manifested on the occasion; but, most unfortunately, there existed an invincible prejudice against every proposition that could be offered, from a general impression as to the utter hopelessness of any attempt to discover a remedy. A few philosophic individuals, however, did form themselves, as we shall presently learn, into an association for the laudable purpose of inviting the attention of scientific men to the subject, and of obtaining from them any suggestions which might lead to a more secure method of lighting the mines.

To the Reverend Dr. Gray, the present Lord Bishop of Bristol, who, at the period to which I allude, was the Rector of Bishop-Wearmouth, and one of the most zealous and intelligent members of the association, I beg to offer my public acknowledgments and thanks for the several highly interesting communications and letters with which his Lordship has obliged me, and by means of which I have been enabled to present to the scientific world a complete history of those proceedings which have so happily led to a discovery, of which it is not too much to say that it is, at once, the pride of science, the triumph of humanity, and the glory of the age in which we live.

In a letter I had lately the honour of receiving from that learned prelate, his Lordship says, "It was at a time when all relief was deemed hopeless, that Mr. Wilkinson, a barrister in London, and a gentleman distinguished for the humanity of his disposition, suggested the expediency of establishing a society for the purpose of enquiring whether any, and what, methods of security might be adopted for the prevention of those accidents so frequently occurring in the collieries of Northumberland and Durham.

"In consequence of this benevolent suggestion, a society was established at Bishop-Wearmouth, on the 1st of October 1813, by Sir Ralph Milbanke, afterwards Sir Ralph Noel, Dr. Gray, Dr. Pemberton, Mr. Robinson, Mr. Stephenson, and several other gentlemen. It was entitled, 'A Society for preventing Accidents in Coal-Mines;' and it immediately obtained the patronage of the Bishop of Durham, the Duke of Northumberland, and other noblemen and gentlemen.

"A very few days before the first meeting, twenty-seven persons had been killed in a colliery in which Sir Ralph Milbanke had an interest, and he was called upon at the meeting to state the particulars of the accident. At that time there was such little expectation that any means could be devised to prevent the occurrence of these explosions, that the object of the gentlemen who convened the meeting, however humane in principle, was considered by the persons present as chimerical and visionary. The Society, however, amidst many difficulties and considerable discouragement, and a perpetual harass by the offer of impracticable schemes from every quarter, nevertheless persevered in their meetings, and succeeded in establishing a communication and correspondence with other Societies in different parts of the kingdom."[27]

[27] It is unnecessary to enumerate the various schemes that
have been proposed to prevent accidents from fire-damp. Some
were unquestionably of value, and might, by their adoption, have
diminished the frequency of explosions; others were visionary,
or wholly impracticable. It was proposed, for instance, to fill
the mine with an atmosphere of chlorine, which by entering into
chemical union with the carburetted hydrogen, might disarm it of
its power. Dr. Murray, in a paper published in the Transactions
of the Royal Society of Edinburgh, suggests the use of a lamp
that shall be supplied with air from the ground of the pit, by
means of a long flexible tube, upon the false assumption that
the fire-damp alone occupies the higher parts of the mine. Mr.
W. Brandling also constructed a Safe-lamp, which, like that of
Dr. Murray, was fed by air introduced through a long flexible
tube reaching to the floor of the mine. In addition to which, he
attached to the top of the lantern a pair of double bellows, by
the aid of which he at the same time drew out the contaminated
air from the interior of the lamp, and sucked in, through the
flexible tube, a fresh portion to supply its place. To say
nothing of the inefficacy and inconvenience of the long tube, the
bellows possessed the additional objection of frequently puffing
out the light.

One of the most active and intelligent members of the "Society
for preventing accidents in Coal Mines," Dr. Clanny, had for some
time paid particular attention to the object in contemplation.
He first suggested the idea of an insulated lamp, of which an
account appeared in the Philosophical Transactions for 1813.
In 1815, he invented a steam safety-lamp, constructed of the
strongest tinned iron, with thick flint glass in front. In this
machine, the air of the coal mine passes in a current through
a tube, and mixing with the steam, before it can arrive at the
light, burns steadily in the wick of the lamp alone. This lamp
has the valuable property of remaining cool. It has been much
used in the Herrington Mill pit, the Whitefield pit, and the
Engine pit.

"One of the projects offered was, that electrical machines should be employed, with ramifications to extend through all the departments of the collieries, and which were to be excited in discharging their fluid in constant succession, in order gradually to destroy the inflammable air. Many other suggestions were proposed, the principal of which were formed with the intention of purifying the air of the pits by chemical processes, or by forcing in large quantities of atmospheric air, through pipes and tunnels, &c.

"The Society, although it received some distinguished patronage, was not furnished with means sufficiently ample for exciting emulation by premiums, or even for defraying the expenses of intelligent artisans; and it unfortunately lost a considerable portion of its funds by the failure of the Wear Bank.

"Amongst the applications which more particularly excited the attention of the Society, was that of Mr. Ryan of Donegal, who objected to the principle upon which the working of collieries was carried on. He conceived that they should be originally constructed at the commencement of the working, with a view to admit the escape of the hydrogen gas to the highest parts of the colliery. He proposed to ventilate even the foulest pits, and the attention of the gentlemen proprietors, or occupiers of collieries, in the neighbourhood of Newcastle, was called upon at public meetings, and an enquiry set on foot with respect to the validity of his pretensions. Some gentlemen were even deputed to proceed into Staffordshire to ascertain the nature and extent of his services in that county, where he had been for some time employed. An offer was also made to place under his management the Hecton pit, at Hepburn, which was particularly foul; but a difference of opinion having arisen as to the efficacy of his plan, he did not consider himself sufficiently encouraged to proceed, and he left the country dissatisfied. He afterwards received the gold medal from the Society for promoting the Arts and Sciences."

The Society having as yet effected but little towards the great object of their deliberations, the chairman of the committee, Dr. Gray, who was generally acquainted with Sir Humphry Davy, judged it expedient to direct his attention to a subject, upon which, of all men of science, he appeared to be the best calculated to bring his extensive stores of chemical knowledge to a practical bearing.

As the life of this valuable man is now closed, and as every incident in it is interesting as connected with the advancement of philosophical knowledge, and especially of chemical discoveries important to the welfare of mankind, it may be worth while to enter into a review of the proceedings which were adopted upon this occasion, in order to trace the progress of the discoveries which were made, and the methods by which he arrived at his conclusions.

Dr. Gray, the chairman of the committee, having addressed to him a letter with a view to engage him in an investigation so important to society, received from him the following answer.

TO THE REVEREND DR. GRAY.

SIR,

August 3, 1815.

I had the honour of receiving the letter which you addressed to
me in London, at this place, and I am much obliged to you for
calling my attention to so important a subject.

It will give me great satisfaction if my chemical knowledge can
be of any use in an enquiry so interesting to humanity, and I
beg you will assure the Committee of my readiness to co-operate
with them in any experiments or investigations on the subject.

If you think my visiting the mines can be of any use, I will
cheerfully do so.

There appears to me to be several modes of destroying the
fire-damp without danger; but the difficulty is to ascertain
when it is present, without introducing lights which may
inflame it. I have thought of two species of lights which
have no power of inflaming the gas which is the cause of the
fire-damp, but I have not here the means of ascertaining
whether they will be sufficiently luminous to enable the
workmen to carry on their business. They can be easily
procured, and at a cheaper rate than candles.

I do not recollect any thing of Mr. Ryan's plan: it is possible
that it has been mentioned to me in general conversation, and
that I have forgotten it. If it has been communicated to me in
any other way, it has made no impression on my memory.

I shall be here for ten days longer, and on my return South,
will visit any place you will be kind enough to point out to
me, where I may be able to acquire information on the subject
of the coal gas.

Should the Bishop of Durham be at Auckland, I shall pay my
respects to his Lordship on my return.

I have the honour to be, dear Sir, with much respect, your
obedient humble servant,

H. DAVY.
At Lord Somerville's, near Melrose, N. B.

TO THE SAME.

SIR, Melrose, August 18, 1815.

I received your letter, which followed me to the Moors, where I
have been shooting with Lord Somerville. I should have replied
to it before this time, but we were in a part of the Highlands
where there was no post. I am very grateful to you for the
obliging invitation it contains.

I propose to leave the Tweed side on Tuesday or Wednesday, so
that I shall be at Newcastle either on Wednesday or Thursday.
If you will have the kindness to inform me by a letter,
addressed at the Post Office, where I can find the gentleman
you mention, I will call upon him, and do any thing in my power
to assist the investigation in that neighbourhood.

I regret that I cannot say positively whether I shall be at
Newcastle on Wednesday or Thursday; for I have some business at
Kelso which may detain me for a night, or it may be finished
immediately.

I am travelling as a bachelor, and will do myself the honour of
paying my respects to you at Bishop-Wearmouth towards the end
of the week.

I am, Sir, with much respect,
Your obedient humble servant,
H. DAVY.

The gentleman alluded to in the preceding letter, and to whom Dr. Gray wished Sir H. Davy to apply, was Mr. Buddle, a person whose extensive practical knowledge has justly entitled him to be considered as the highest authority on all subjects connected with the art of mining, and who has conferred inestimable benefits on the mining interests by the introduction of successful methods of ventilation. The account of his interview with Sir H. Davy is communicated in the following letter.

MR. BUDDLE TO DR. GRAY.

Wall's-end Colliery, August 24, 1815.

SIR,

Permit me to offer my best acknowledgments for the opportunity
which your attention to the cause of humanity has afforded me
of being introduced to Sir Humphry Davy.

I was this morning favoured with a call from him, and he
was accompanied by the Rev. Mr. Hodgson. He made particular
enquiries into the nature of the danger arising from the
discharge of the inflammable gas in our mines. I shall supply
him with a quantity of the gas to analyze; and he has given me
reason to expect that a substitute may be found for the steel
mill, which will not fire the gas. He seems also to think it
possible to generate a gas, at a moderate expense, which, by
mixing with the atmospheric current, will so far neutralize the
inflammable air, as to prevent it firing at the candles of the
workmen.

If he should be so fortunate as to succeed in either the one or
the other of these points, he will render the most essential
benefit to the mining interest of this country, and to the
cause of humanity in particular.

I have little doubt but it will be gratifying to you to be
informed, that progress is making towards the establishment of
a permanent fund for the relief of sufferers by accident and
sickness in the collieries of this district.

I have the pleasure to remain, with great respect, Sir, your
most obedient, humble servant,

John Buddle.

Sir H. Davy on his return to London, having been supplied by Mr. Buddle with various specimens of _fire-damp_, proceeded, in the first instance, to submit to a minute chemical examination the substance with which he had to contend.

In less than a fortnight, he informed Dr. Gray by letter, that he had discovered some new and unexpected properties in the gas, which had led to no less than four different plans for lighting the mines with safety.

TO THE REVEREND DR. GRAY.

Royal Institution, Oct. 30.

MY DEAR SIR,

As it was the consequence of your invitation that I endeavoured
to investigate the nature of the fire-damp, I owe to you the
first notice of the progress of my experiments.

My results have been successful far beyond my expectations.
I shall enclose a little sketch of my views on the subject;
and I hope in a few days to be able to send a paper with the
apparatus for the committee.

I trust the _Safe lamp_ will answer all the objects of the
collier.

I consider this at present as a _private_ communication. I wish
you to examine the lamps I have had constructed, before you
give any account of my labours to the committee.

I have never received so much pleasure from the result of any
of my chemical labours; for I trust the cause of humanity will
gain something by it.

I beg of you to present my best respects to Mrs. Gray, and to
remember me to your son.

I am, my dear Sir, with many thanks for your hospitality and
kindness when I was at Sunderland, your obliged servant,

H. DAVY.

TO THE SAME.

London, October 31, 1815.

MY DEAR SIR,

I sent yesterday a sketch of my results on the fire-damp.
We have lately heard so much of East[28] Shields, that by a
strange accident I confounded it with Bishop-Wearmouth, and
addressed your letter to East Shields.

I could not find any body to frank it, and you will find it a
heavy packet; however, I could not lose a moment in giving you
an account of results which I hope may be useful to humanity.

If my letter has not reached you, it will be found at the Post
Office, East Shields.

With respects to Mrs. Gray, I am, my dear Sir, very sincerely
yours,

H. DAVY.

[28] _Quere_--South Shields.

The sketch alluded to in the foregoing letter, has been kindly placed in my hands by the Bishop of Bristol; it possesses considerable interest as an original document, displaying his earliest views, and tending to illustrate the history of their progress.

"The fire-damp I find, by chemical analysis, to be (as it
has been always supposed) a hydro-carbonate. It is a chemical
combination of hydrogen gas and carbon, in the proportion of 4 by
weight of hydrogen gas, and 11-1/2 of charcoal.

"I find it will not explode, if mixed with less than six times,
or more than fourteen times its volume of atmospheric air. Air,
when rendered impure by the combustion of a candle, but in which
the candle will still burn, will not explode the gas from the
mines; and when a lamp or candle is made to burn in a close vessel
having apertures only above and below, an _explosive mixture_
of gas admitted _merely enlarges_ the light, and then gradually
extinguishes it without explosion. Again,--the gas mixed in any
proportion with common air, I have discovered, _will not explode_
in a _small tube_, the diameter of which is less than 1/8th of an
inch, or even a larger tube, if there is a mechanical force urging
the gas through this tube.

"Explosive mixtures of this gas with air require much stronger heat
for their explosion than mixtures of common inflammable gas.[29]
Red-hot charcoal, made so as not to flame, if blown up by a
mixture of the mine gas and common air, does not explode it, but
gives light in it; and iron, to cause the explosion of mixtures of
this gas with air, must be made _white_-hot.

"The discovery of these curious and unexpected properties of the
gas, leads to several practical methods of lighting the mines
without any danger of explosion.

"The first and simplest is what I shall call the _Safe lamp_, in
which a candle or a lamp burns in a safe lantern which is air-tight
in the sides, which has tubes below for admitting air, a chamber
above, and a chimney for the foul air to pass through; and this
is as portable as a common lantern, and not much more expensive.
In this, the light never burns in its full quantity of air, and
therefore is more feeble than that of the common candle.

"The second is the _Blowing lamp_. In this, the candle or lamp
burns in a close lantern, having a tube below of small diameter
for admitting air, which is thrown in by a small pair of bellows,
and a tube above of the same diameter, furnished with a cup filled
with oil. This burns brighter than the simple safe lamp, and is
extinguished by explosive mixtures of the fire-damp. In this
apparatus the candle may be made to burn as bright as in the air;
and supposing an explosion to be made in it, it cannot reach to the
external air.

"The third is the _Piston lamp_, in which the candle is made
to burn in a small glass lantern furnished with a piston, so
constructed as to admit of air being supplied and thrown into it
without any communication between the burner and the external air:
this apparatus is not larger than the steel-mill, but it is more
expensive than the other, costing from twenty-two to twenty-four
shillings.

"These lamps are all extinguished when the air becomes so polluted
with fire-damp as to be explosive.

"There is a fourth lamp, by means of which any _blowers_ may be
examined in air in which respiration cannot be carried on: that is,
the _Charcoal lamp_. This consists of a small iron cage on a stand,
containing small pieces of _very well burnt_ charcoal blown up to
a red heat. This light will not inflame any mixtures of air with
fire-damp.[30]

"Of these inventions, the _Safe lamp_, which is the simplest, is
likewise the one which affords the most perfect security, and
requires no more care or attention than the common candle, and
when the air in mines becomes improper for respiration, it is
extinguished, and the workmen ought immediately to leave the place
till a proper quantity of atmospheric air can be supplied by
ventilation.

"I have made many experiments on these lamps with the genuine
fire-damp taken from a blower in the Hepburn Colliery, collected
under the inspection of Mr. Dunn, and sent to me by the Reverend
Mr. Hodgson. My results have been always unequivocal.

"I shall immediately send models of the different lamps to such of
the mines as are exposed to danger from explosion; and it will be
the highest gratification to me to have assisted by my efforts a
cause so interesting to humanity."

[29] _Olefiant_ gas, when mixed with such proportions of common
air as to render it explosive, is fired both by charcoal and
iron heated to a dull-red heat. _Gaseous oxide of carbon_,
which explodes when mixed with two parts of air, is likewise
inflammable by red-hot iron, and charcoal. The case is the same
with _sulphuretted hydrogen_.

[30] "In addition to these four lamps, we learn from an Appendix
to his Paper in the Philosophical Transactions, that in the
beginning of his enquiries, he constructed a close lantern, which
he called the _Fire-valve lantern_; in which the candle or lamp
burnt with its full quantity of air, admitted from an aperture
below, till the air began to be mixed with fire-damp, when, as
the fire-damp increased the flame, a thermometrical spring at the
top of the lantern, made of brass and steel, riveted together,
and in a curved form, expanded, moved a valve in the chimney,
diminished the circulation of air, and extinguished the flame. He
did not, however, pursue this invention, after he had discovered
the properties of the fire-damp, on which his Safety-lamp is
founded."

Contrary to the wish expressed by Sir Humphry Davy, the foregoing communication was inadvertently read at a public meeting of the Coal-trade, which was held at Newcastle on the 3rd of November: a circumstance which occasioned some embarrassment at the time, but is satisfactorily explained in the following letter from Sir Humphry.

TO THE REVEREND DR. GRAY.

23, Grosvenor Street, Dec. 14, 1815.

MY DEAR SIR,

My communication to ---- was, like that I made to you, intended
to be _private_; he has however written to me to apologize for
having made it known at Newcastle, stating, that having seen a
notice of my results in the paper, the motive, as he conceived,
for withholding it was at an end, as he considered my only
reason for wishing to keep back my results from the public eye
was the conviction that they might be rendered more perfect,
and this I have now fully proved.

I trust I shall be able in a very few days to send you a model
of a lantern nearly as simple as a common glass lantern, and
which _cannot_ communicate explosion to the fire-damp. I will
send another to Newcastle, and I will likewise send you the
copy of my paper, which you may reprint in any form you please;
you will find my acknowledgments to you publicly stated.

My principles are these: _First_, a certain mixture of
azote and carbonic acid prevents the explosion of the
fire-damp, and this mixture is necessarily formed in the safe
lantern;--_Secondly_, the fire-damp _will not explode_ in tubes
or feeders of a certain small diameter. The ingress into, and
egress of air from my lantern is through such tubes or feeders;
and therefore, when an explosion is _artificially_ made in the
safe lantern, it does not communicate to the external air.

I have made two or three lanterns of different forms.
Experience must determine which will be the most convenient.

Should there be a little delay in sending them, it will be the
fault of the manufacturer. It is impossible to conceive the
difficulty of getting any thing made in London which is not in
the common routine of business; and I should be very sorry to
send you any thing imperfectly executed.

With best respects to Mrs. Gray, I am, my dear Sir,

Very sincerely your obliged servant,
H. DAVY.

The paper alluded to in the preceding letter, entitled, "On the Fire-damp of Coal Mines, and on methods of lighting the mine so as to prevent its explosion," was read before the Royal Society on the 9th of November, 1815.

In this memoir he communicates the results of some chemical experiments upon the nature of the fire-damp, and announces the existence of certain properties in that gas, which had previously escaped observation, and which leads to very simple methods of lighting the mines without danger.

He confirms the opinion of Dr. Henry, and other chemists, as to the fire-damp being light carburetted hydrogen gas, and analogous to the inflammable gas of marshes; but he found that the degree of its combustibility differed most materially from that of the other common inflammable gases, which it is well known will explode by the contact of both red-hot iron and charcoal; whereas well-burned charcoal, ignited to the strongest red heat, did not explode any mixture of the air and of the fire-damp; and a fire made of well-burned charcoal, that is to say, of charcoal that will burn without flame, was actually blown up to whiteness by an explosive mixture containing the fire-damp without producing its inflammation.[31] An iron rod also, at the highest degree of _red_ heat, and even at the common degree of _white_ heat, did not inflame explosive mixtures of the fire-damp; but when in brilliant combustion, it produced the effect.

[31] Whence he observes that, if it be necessary to be present
in a part of the mine where the fire-damp is explosive, for the
purpose of clearing the workings, taking away pillars of coal, or
other objects, the workmen may be safely lighted by a fire made
of charcoal, which burns without flame.

He moreover found that the heat produced by the combustion of the fire-damp was much less than that occasioned by most other inflammable gases under similar circumstances; and hence its explosion was accompanied with comparatively less expansion: a circumstance of obvious importance in connection with the propagation of its flame.

Numerous experiments were likewise instituted by him with a view to determine the proportions of air with which the fire-damp required to be mixed, in order to produce an explosive atmosphere; and he found the quantity necessary for that purpose to be very considerable; even when mixed with three or nearly four times its bulk of air, it burnt quietly in the atmosphere, and extinguished a taper. When mixed with between five and six times its volume of air, it exploded freely. The mixture which seemed to possess the greatest explosive power was that of seven or eight parts of air to one of gas.

On adding azote and carbonic acid in different proportions to explosive mixtures of fire-damp, it was observed that, even in very small quantities, these gases diminished the velocity of the inflammation, or altogether destroyed it. In this stage of the enquiry, the important fact was discovered, that explosive mixtures could not be fired in metallic tubes of certain lengths and diameters.[32] In exploding, for instance, a mixture of one part of gas from the distillation of coal, and eight parts of air, in a tube of a quarter of an inch in diameter and A foot long, more than a second was required before the flame reached from one end of the tube to the other; and not any mixture could be made to explode in a glass tube of one-seventh of an inch in diameter. In pursuing these experiments, he found that, by diminishing its diameter, he might in the same ratio shorten the tube without danger; and that the same principle of security was obtained by diminishing the length and increasing the number of the tubes, so that a great number of small apertures would not pass explosion when their depth was equal to their diameter. This fact led him to trials upon sieves made of wire-gauze, or metallic plates perforated with numerous small holes, and he found that it was impossible to pass explosions through them.[33]

[32] Mr. Tennant had, some years before, observed that mixtures
of the gas, from the distillation of coal, and air, would not
explode in very small tubes. Davy, however, was not aware of this
at the time of his researches.

[33] The apertures in the gauze should not be more than
one-twentieth of an inch square. As the fire-damp is not inflamed
by ignited wire, the thickness of the wire is not of importance;
but wire from one-fortieth to one-sixtieth of an inch in diameter
is the most convenient.