CHAPTER XI.

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Safety-lamp.--Safety-tubes superseded by Safety-canals.--Flame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.

In reasoning upon these several phenomena, it occurred to him,

that as a high temperature was required for the inflammation of

the fire-damp, and as it produced in burning, comparatively, _a

small degree_ of heat, the effect of carbonic acid and azote, as

well as that of the surfaces of small tubes, in preventing its

explosion, depended upon their cooling powers; that is to say, upon

their lowering the temperature of the exploding mixture to such

a degree, that it was no longer sufficient for its continuous

inflammation. In support of this theory, he ascertained that

metallic tubes resisted the passage of the flame more powerfully

than glass tubes of similar lengths and diameters, metal being the

better conductor of heat; and that carbonic acid was more effective

than azote in depriving the fire-damp of its explosive power, in

consequence, as he considered, of its greater capacity for heat,

and likewise of a higher conducting power connected with its

greater density.

In this short statement, the reader is presented with the whole

theory and operation of the Safety-lamp, which is nothing more

than an apparatus by which the inflammable air, upon exploding

in its interior, cannot pass out without being so far cooled, as

to deprive it of the power of communicating inflammation to the

surrounding atmosphere. The principle having been once discovered,

it was easy to adopt and multiply practical applications of it.

From the result of these researches, it became at once evident,

that to light mines infested with fire-damp, with perfect security,

it was only necessary to use an air-tight lantern, supplied with

air from tubes of small diameter, through which explosions cannot

pass, and with a chimney, on a similar principle, at the upper

part, to carry off the foul air. A common lantern, to be adapted

to the purpose, merely required to be made air-tight in the door

and sides, and to be furnished with the chimney, and the system of

safety apertures below and above the flame of the lamp. Such, in

fact, was Davy's first Safety-lamp; and having afterwards varied

the arrangement of the tubes in different ways, he at length

exchanged them for canals, which consisted of close concentric

hollow metallic cylinders of different diameter, so placed together

as to form circular canals of the diameter of from one-twenty-fifth

to one fortieth of an inch; and of an inch and seven-tenths in

length; by which air is admitted in much larger quantities than

by the small tubes, and they are moreover much superior to the

latter in practical application. He also found, that longitudinal

air-canals of metal might be employed with the same security as

circular canals; and that a few pieces of tin plate, soldered

together with wires to regulate the diameter of the canal, answered

the purpose of the feeder or safe chimney, as well as drawn

cylinders of brass.

The subjoined explanatory sketches will assist in rendering

the scheme intelligible, and obviate the possibility of any

misconception of the subject.

[Illustration]

FIG. 1. represents the first Safe lantern, with its air-feeder

and chimney furnished with safety metallic canals. The sides are

of horn or glass, made air-tight by putty or cement. A. is the

lamp through which the circular air-feeding canals pass. B. is the

chimney containing four such canals; above it is a hollow cylinder,

with a cap to prevent dust from passing into the chimney. C. is

the hole for admitting oil. F. is the rim round the bottom of the

lantern, to enable it to bear motion.

[Illustration]

FIG. 2. exhibits an enlarged view of the safety concentric canals,

which, if one-twenty-fifth of an inch in diameter, must not be less

than two inches in exterior circumference, and one-seventh of an

inch high.

[Illustration]

FIG. 3. exhibits the longitudinal safety canals.

[Illustration]

FIG. 4. represents a Safety-lamp having a glass chimney, covered

with tin-plate, and the safety apertures in a cylinder with a

covering above: the lower part is the same as in the lantern.

[Illustration]

FIG. 5. A glass tube furnished with _flame sieves_, in which a

common candle may be burnt. A A. the flame sieves. B. a little

plate of metal to prevent the upper flame sieve from being acted on

by the current of hot air.

During the short visit of Sir Humphry Davy at Bishop Wearmouth,

he saw the lamp which Dr. Clanny was then engaged in perfecting.

It has been already observed, that it was secured against the

effects of fire-damp by being supplied with atmospheric air

previously conveyed through water.[34] The machinery of this lamp

was far too cumbrous to be of general use; but its inventor was

justly commended by Davy for his ingenuity and perseverance. It

unfortunately happened that, in consequence of some erroneous

representations made to Dr. Clanny, he received the impression

that Sir Humphry had not been disposed to treat his invention with

sufficient respect, nor had given him the credit to which he was so

justly entitled. This suspicion, which had been long industriously

kept alive, was however ultimately removed.

[34] M. de Humboldt conceived and executed the plan of a lamp in

1796, for giving a safe light in mines, upon a similar principle

of entire insulation from the air.--_Journal des Mines_, t. viii.

p. 839.

The following letter refers to this unfortunate circumstance. I

have adverted to it in these memoirs, for the purpose of showing

what an unfair spirit of rivalry, and what a succession of petty

jealousies were excited by those generous and disinterested labours

of Davy, which ought to have called forth nothing but the most

lively expressions of gratitude for his services, and admiration of

his genius.

TO THE REVEREND DR. GRAY.

23, Grosvenor Street, December 13.

MY DEAR SIR,

A Friend of mine has sent me a newspaper--the Tyne Mercury,

containing a very foolish libel upon me. It states, amongst

other things, that I did not mention Dr. Clanny, or his lamp,

in my late paper read before the Royal Society; whereas I

mentioned his lamp as a very ingenious contrivance, and named

him amongst the gentlemen who obligingly furnished me with

information upon the subject.

It will be needless for me to point out to you that my lamp

has no one principle in common with that of Dr. Clanny. He

forces in his air through water by bellows. In mine, the air

passes through safety canals without any mechanical assistance.

Mine is a common lantern made close, and furnished with safety

canals.

I hope I shall not hear that Dr. Clanny has in any way

authorized or promoted so improper a statement as that in the

Tyne Mercury; indeed, I do not think it possible.

I have at last obtained a complete model of my lamp, after many

disappointments from the instrument-maker. I hope in a few days

to send you a _Safe lantern_, as portable as a common-made one,

and the perfect security of which is demonstrable.

I am, my dear Sir, your sincerely obliged,

H. DAVY.

TO THE SAME.

Grosvenor Street, December 15.

MY DEAR SIR,

I shall inclose the first sheet of my paper, and shall be glad

to preface it by some observations when you reprint it.

I shall forward my lanterns and lamps to you in a few days.

They are _absolutely_ safe; and if the miners have any more

explosions from their light, it will be their own fault.

You will find, when you see my construction, that the

principles as well as the execution are entirely new.

You will find in the second sheet of my paper, which I hope to

be able to send to-morrow, the _principles_ of _security_, and

its limits unfolded.

I am, my dear Sir, very sincerely yours,

H. DAVY.

TO THE SAME.

London, January 1, 1816.

MY DEAR SIR,

I fear you will have accused me of procrastination in delaying

to send you my papers and my lamps.

The papers read to the Royal Society have been printed; but

during the period that has elapsed since I last wrote to you,

I have made a discovery much more important than those which I

have already had the honour of communicating to you.

I have made very simple and economical lanterns, and candle

guards, which are not only _absolutely safe_, but which give

light by means of the fire-damp, and which, while they disarm

this destructive agent, make it useful to the miner.

This discovery is a consequence of that which I communicated

to you in my last letter on the wire sieves. I hope to be able

to send you on Wednesday the printed account of my results,

together with models of lamps which will burn and consume all

explosive mixtures of the fire-damp.

I have at last finished my enquiries with perfect satisfaction

to myself, and I feel highly obliged to you for having called

my attention to a subject where my labours will, I hope, be of

some use.

I am, my dear Sir, very sincerely yours,

H. DAVY.

It is impossible to approach the consideration of this last, the

most signal and splendid of his triumphs, without feelings of the

highest satisfaction. He had already, as we have seen, disarmed the

fire-damp of its terrors, it only remained for him to enlist it

into his service. The simple means by which this was effected are

as interesting as their results are important.[35]

[35] "An Account of an Invention for giving Light in explosive

mixtures of Fire-damp in Coal Mines, by consuming the Fire-damp."

Read before the Royal Society, Jan. 11, 1816.

Davy had previously arrived at the fact, that wire-gauze might be

substituted as air-feeders to the lamp, in the place of his tubes

or safety canals; but not until after the lapse of several weeks,

did the happy idea of constructing the lamp entirely of wire-gauze

occur to him:--the history of this elaborate enquiry affords a

striking proof of the inability of the human mind to apprehend

simplicities, without a process of complication which works as the

grappling machinery of truth.

His original lamp with tubes or canals, as already described, was

perfectly safe in the most explosive atmosphere, but its light was

necessarily extinguished by it; whereas in the wire-gauze cage,

the fire-damp itself continues to burn, and thus to afford to the

miner a useful light, while he is equally secured from the fatal

effects of explosion.

[Illustration]

All then required for his guidance and protection in the darkness

of the mine, are candles or lamps surrounded by small wire cages,

which will at once supply air to the flame, and light to the miner;

they may be obtained for a few pence, and be variously modified as

circumstances may render necessary.

The reader is here presented with a sketch of the gauze instrument,

in its first and simplest form. The original lamp is preserved in

the laboratory of the Royal Institution.

Nothing now remained but to ascertain the degree of fineness

which the wire-gauze ought to possess, in order to form a secure

barrier against the passage of flame. For this purpose, Davy

placed his lighted lamps in a glass receiver, through which there

was a current of atmospherical air, and by means of a gasometer

filled with coal gas, he made the current of air which passed into

the lamp more or less explosive, and caused it to change rapidly

or slowly at pleasure, so as to produce all possible varieties

of inflammable and explosive mixtures; and he found that iron

wire-gauze composed of wires from one-fortieth to one-sixtieth of

an inch in diameter, and containing twenty-eight wires, or seven

hundred and eighty-four apertures to the inch, was safe under all

circumstances in atmospheres of this kind; and he consequently

employed that material in guarding lamps for the coal mines, where,

in January 1816, they were immediately adopted, and have long been

in general use.

Observations upon them in their working state, and upon the

circumstances to which they are exposed, have led to a few

improvements or alterations, merely connected with the modes of

increasing light or diminishing heat, which were obvious from the

original construction.

[Illustration]

The annexed woodcut represents the lamp which is in present use.

A is a cylinder of wire-gauze, with a double top, securely and

carefully fastened, by doubling over, to the brass rim B, which

screws on to the lamp C. The whole is protected by strong iron

supports D, to which a ring is affixed for the convenience of

carrying it.

In a paper read before the Royal Society, on the 23rd of January

1817, entitled, "Some new Experiments and Observations on the

Combustion of Gaseous Mixtures, with an Account of a method of

preserving a continued Light in mixtures of inflammable Gases and

Air without Flame," Sir H. Davy announces the application of a

principle which he had discovered in the progress of his researches

for increasing the utility of the Safety-lamp, and which, a century

ago, would have unquestionably exposed its author to the charge of

witchcraft.

Having ascertained that the temperature of flame is infinitely

higher than that necessary for the ignition of solid bodies,

it appeared to him probable that, in certain combinations of

gaseous bodies, although the increase of temperature might not

be sufficient to render the gaseous matters themselves luminous,

they might nevertheless be adequate to ignite solid matters

exposed to them. During his experiments on this subject, he was

led to the discovery of the curious phenomenon of slow combustion

without flame. He observes, that there cannot be a better mode

of illustrating the fact, than by an experiment on the vapour of

ether or of alcohol. Let a few coils of wire of platinum of the

one-sixtieth or one-seventieth of an inch be heated by a hot poker

or candle, and let it be brought into the glass; it will presently

become glowing, almost white hot, and will continue so, as long as

a sufficient quantity of vapour and of air remain in the glass.[36]

[36] This principle has been applied for constructing what has

been termed the _Aphlogistic Lamp_, which is formed by placing

a small coil of platinum wire round the wick of a common spirit

lamp. When the lamp, after being lighted for a few moments,

is blown out, the platinum wire continues to glow for several

hours, as long as there is a supply of spirit of wine, and to

give light enough to read by; and sometimes the heat produced

is sufficient to rekindle the lamp spontaneously. The same

phenomena are produced by the vapour of camphor; and an aromatic

fumigating lamp has lately been advertised for sale, which is no

other than the contrivance above described; and it is evident

that, if the spirit be impregnated with fragrant principles, an

aromatic vinegar will be developed during its slow combustion,

and diffused in fumes through the apartment.

This experiment on the slow combustion of ether is accompanied with

the formation of a peculiar acrid and volatile substance possessed

of acid properties, which has been particularly examined by Mr.

Daniell, who, having at first regarded it as a new acid, proposed

for it the name of _Lampic_ acid, in allusion to the researches

which led to its discovery; he has, however, since ascertained that

its acidity is owing to the acetic acid, which is combined with

some compound of carbon and hydrogen, different both from ether and

alcohol.

The phenomena of slow combustion, as exhibited in certain states of

the mine, by the Safety-lamp, are highly curious and interesting.

By suspending some coils of fine wire of platinum[37] above

the wick of his lamp, the miner will be supplied with light in

mixtures of fire-damp no longer explosive; for should his flame

be extinguished by the quantity of fire-damp, the little coil of

platinum will begin to glow with a light sufficiently bright to

guide him in what would otherwise be impenetrable darkness, and to

lead him into a purer atmosphere, when the heat thus increased will

very frequently be sufficient to rekindle his lamp!

[37] Sir Humphry Davy attempted to produce the phenomena with

various other metals, but he only succeeded with platinum and

palladium; these bodies have low conducting powers, and small

capacities for heat, in comparison with other metals, which seem

to be the causes of their producing, continuing, and rendering

sensible, these slow combustions.

In this case it will be readily perceived, that the combustion of

the fire-damp is continued so slowly, and at so low a temperature,

as not to be adequate to that ignition of gaseous matter which

constitutes flame, although it excites a temperature sufficient to

render platinum wire luminous.

Sir Humphry Davy observes, that there never can be any danger

with respect to respiration, whenever the wire continues ignited;

for even this phenomenon ceases when the foul air forms about

two-fifths of the volume of the atmosphere.

The experiment, as originally performed by the illustrious chemist,

is so interesting and instructive, that I shall here relate it in

his own words.

"I introduced into a wire-gauze Safe lamp a small cage made of

fine wire of platinum of one-seventieth of an inch in thickness,

and fixed it by means of a thick wire of the same metal about

two inches above the wick which was lighted. I placed the whole

apparatus in a large receiver, in which, by means of a gas-holder,

the air could be contaminated to any extent with coal gas. As soon

as there was a slight admixture of coal gas, the platinum became

ignited; the ignition continued to increase till the flame of the

wick was extinguished, and till the whole cylinder became filled

with flame; it then diminished. When the quantity of coal gas was

increased, so as to extinguish the flame, at the moment of the

extinction the cage of platinum became white hot, and presented a

most brilliant light. By increasing the quantity of the coal gas

still farther, the ignition of the platinum became less vivid:

when its light was barely sensible, small quantities of air were

admitted, its heat speedily increased; and by regulating the

admission of coal gas and air, it again became white hot, and soon

after lighted the flame in the cylinder, which as usual, by the

addition of more atmospherical air, rekindled the flame of the

wick."

I have thus related, somewhat in detail, the history of a

discovery, which, whether considered in relation to its scientific

importance, or to its great practical value, must be regarded as

one of the most splendid triumphs of human genius. It was the

fruit of elaborate experiment and close induction; chance, or

accident, which comes in for so large a share of the credit of

human invention, has no claims to prefer upon this occasion; step

by step, may he be followed throughout the whole progress of his

research, and so obviously does the discovery of each new fact

spring from those that preceded it, that we never for a moment lose

sight of our philosopher, but keep pace with him during the whole

of his curious enquiry.

He commenced, as we have seen, with ascertaining the degree of

combustibility of the fire-damp, and the limits in which the

proportions of atmospheric air and carburetted hydrogen can be

combined, so as to afford an explosive mixture. He was then led to

examine the effects of the admixture of azote and carbonic acid

gas; and the result of those experiments furnished him with the

basis of his first plan of security. His next step was to enquire

whether explosions of gas would pass through tubes; and on finding

that this did not happen, if the tubes were of certain lengths and

diameters, he proceeded to examine the limits of such conditions,

and by shortening the tubes, diminishing their diameters, and

multiplying their number, he at length arrived at the conclusion,

that a simple tissue of wire-gauze afforded all the means of

perfect security; and he constructed a lamp, which has been truly

declared to be as marvellous in its operation, as the storied lamp

of Aladdin, realizing its fabled powers of conducting in safety,

through "fiends of combustion," to the hidden treasures of the

earth. We behold a power which, in its effects, seemed to emulate

the violence of the volcano and the earthquake, at once restrained

by an almost invisible and impalpable barrier of network--we

behold, as it were, the dæmon of fire taken captive by Science,

and ministering to the convenience of the miner, while harmlessly

fluttering in an iron cage.

And yet, wonderful as the phenomenon may appear, his experiments

and reasonings have demonstrated, that the interruption of flame by

solid tissues permeable to light and air, depends upon no recondite

or mysterious cause, but simply upon their cooling powers, which

must always be proportional to the smallness of the mesh, and the

mass of the metal.

When it is remembered that the security thus conferred upon the

labouring community, is not merely the privilege of the age in

which the discovery was effected, but must be extended to future

times, and continue to preserve human life as long as coal is dug

from our mines, can there be found in the whole compass of art or

science, an invention more useful and glorious?

The wire-gauze lamp has now been several years extensively used in

the mines, and the most satisfactory and unequivocal testimonies

have been published of the complete security which it affords. They

have amongst the miners obtained the name of _Davys_; and such is

the confidence of the work men in their efficacy, that by their aid

they enter the most explosive atmospheres, and explore the most

remote caverns, without the least dread of their old enemy the

_fire-damp_.

Into the mines of foreign countries the Safety-lamp has been

introduced with similar success; and the illustrious discoverer has

been repeatedly gratified by accounts of the enthusiasm with which

his invention has been adopted in various parts of Europe.[38]

[38] A pamphlet appeared at Mons, in the year 1818, on the

explosions that occur in coal mines, and on the means of

preventing them by Davy's Safety-lamp. It was published under

the direction of the Chamber of Commerce and Manufactures of

Mons, accompanied by notes, and by the results of a series of

experiments that had been conducted by M. Gossart, President

of the Chamber. The province of Hainault is said to be richer

in coal mines than any other part of the Continent of Europe,

and to have no less than one hundred thousand persons employed

in the working them. The same kind of dangerous accidents

occurred in these mines as in those of the North of England,

and various expedients had been adopted for their prevention,

which, however, availed but little in obviating them. "All the

precautions," observe the reporters, "which had been hitherto

known or practised, had not been able to preserve the unfortunate

miners from the terrible effects of explosion. It is therefore an

inappreciable benefit which we confer by making known the equally

simple and infallible method of preventing these accidents, which

has been discovered by the celebrated Humphry Davy."

M. Gossart gives an ample and accurate detail of the properties

of the explosive gas, and confirms the truth of Davy's

experiments, by which the high temperature necessary for its

inflammation, and the consequent means of preventing it, by

reducing that temperature, as effected during its passage through

wire-gauze, are clearly demonstrated.

The lamp appears from this report to have been as useful in the

mines of Flanders as in those of England. The Pamphlet is a

valuable document, inasmuch as it affords an independent proof of

the security of the instrument, and displays the high sense of

obligation which foreign nations entertain to Sir Humphry Davy

for his invention.

Nor is the utility of this invention limited to the operations of

mining. In gas manufactories, spirit warehouses,[39] or druggists'

laboratories, and in various other situations, where the existence

of an explosive atmosphere[40] may expose persons to danger, the

Safety-lamp may be advantageously used; and as science proceeds in

multiplying the resources of art, this instrument will no doubt be

found capable of many new applications.

[39] The danger of carrying a naked light into an atmosphere

impregnated with the fumes of spirit was awfully exemplified

by the loss of the Kent East Indiaman, by fire, in the Bay of

Biscay, on the 1st of March 1825.

[40] In cases where there is any suspicion of accumulations of

carburetted hydrogen from the leakage of gas pipes, or from other

sources, the safety-lamp should always be employed. A terrible

accident occurred some years since at Woolwich, from a room

filled with the vapour of coal-tar, for the purpose of drying and

seasoning timber intended for ship-building. As the combustion

arose from the flame issuing through the flue, which ran along

the apartment, at the moment the damper was applied at the top

of the building, it is evident that, had a wire-gauze guard

been used, the accident could not have occurred. The house was

completely demolished, and nine persons were unfortunately killed.

By the permission of the President and Council of the Royal

Society, several accounts of these researches, and of the invention

and use of the Safety-lamp were printed, and circulated through the

coal districts.

It might have been fairly expected that, in a district which had

been so continually and so awfully visited by explosions, against

which no human foresight had as yet been able to provide a remedy,

the disinterested services of the greatest chemist of the age would

at least have been received without a dissentient voice, and that

his invention of security would have escaped the common fate of all

great discoveries, and been accepted with every homage of respect

and gratitude; but the inventor of the Safety-lamp was doomed to

encounter a bitter hostility from persons whom a spirit of rivalry,

or a feeling of hopeless emulation, had cemented into a faction.

From the period of the first announcement of the Safety-lamp, a

prejudice against its use was industriously circulated amongst the

miners; and some persons even maintained the monstrous proposition,

that any protection against the explosions of fire-damp would

injure more than it could serve the collier, by inducing him to

resume abandoned works, and thus continually to inhale a noxious

atmosphere.

The utility of the lamp having been established, in spite of every

opposition, the claims of Sir H. Davy to its invention were next

publicly challenged.

It will hereafter be scarcely believed that an invention so

eminently philosophic, and which could never have been derived

but from the sterling treasury of science, should have been

claimed in behalf of an engine-wright of Killingworth, of the name

of Stephenson--a person not even professing a knowledge of the

elements of chemistry. As the controversy to which this claim gave

birth has long since subsided, I would willingly have treated it as

a passing cloud, had not its shadow remained. The circumstances,

however, of the transaction stand recorded in the Magazines of the

day, and the biographer of Davy would compromise his rights, by

omitting to notice the attempts that have been made to invalidate

them.

The claims which were made for the priority of Mr. Stephenson's

invention of the Safety-lamp were urged in several communications

in the Newcastle Courant. It has been said in reply, that if dates

were taken as evidence, not merely of priority, but of originality

of invention, it must follow that Mr. Stephenson's lamp was derived

from that of Sir H. Davy. With regard to the first of Stephenson's

lamps, the only one upon which the shadow even of a claim can

be founded, it is unnecessary for the friends of truth to adopt

such a line of defence; indeed, after a deliberate examination of

all that has been published on the subject, I am very willing to

believe that Mr. Stephenson did construct the lamp which dates

its origin from the 21st of October 1815, without any previous

knowledge of the conclusions at which Davy had arrived; for it was

first announced to the Coal-trade by Mr. R. Lambert on the 3rd of

November, to the very meeting at which Sir H. Davy's private letter

was inadvertently read.--But what were the principles, and what the

construction of this lamp?

It would appear that Mr. Stephenson had entertained some vague

notion of the practicability of consuming the fire-damp as fast as

it entered the lamp, and that if admitted only in small quantities,

it would not explode the surrounding atmosphere: for effecting

this object, he constructed a lamp with an orifice, over which

was placed a slide, by the movement of which the opening could be

enlarged, or diminished, and the volume of fire-damp to be admitted

into the lamp regulated according to circumstances. Now such a lamp

could be nothing else than an exploding lamp; for to make it burn

in common air, the orifice must have been so wide that, on going

into an explosive atmosphere, the combustion in the interior could

not have failed to pass it, and to have exploded the mine. Here

then is a _safety_-lamp, which as long as it is safe, will not

burn, and the moment it begins to burn, it becomes unsafe!

The testimonies in favour of the security afforded by this lamp

were evidently procured from persons who were not only ignorant

of the principles of its construction, but of the methods to be

pursued for ascertaining its safety. I am surely justified in such

a statement, when, instead of an _explosive mixture_, I find them

throwing in _pure fire-damp_, which will always extinguish flame,

whether burning in a safe or unsafe lamp.