Lives of the Engineers Part 8

He was soon at the bottom, and in the midst of the men, who were paralysed by the danger which threatened the lives of all in the pit.

Leaping from the corve on its touching the ground, he called out; "Are there six men among you who have courage to follow me? If so, come, and we will put the fire out." The Killingworth pitmen had the most perfect confidence in their engine-wright, and they readily volunteered to follow him.

[Picture: The Pit Head, West Moor]

Silence succeeded the frantic tumult of the previous minute, and the men set to work with a will. In every mine, bricks, mortar, and tools enough are at hand, and by Stephenson's direction the materials were forthwith carried to the required spot, where, in a very short time a wall was raised at the entrance to the main, he himself taking the most active part in the work. The atmospheric air was by this means excluded, the fire was extinguished, the people were saved from death, and the mine was preserved.

This anecdote of Stephenson was related to the writer, near the pit-mouth, by one of the men who had been present and helped to build up the brick wall by which the fire was stayed, though several workmen were suffocated. He related that, when down the pit some days after, seeking out the dead bodies, the cause of the accident was the subject of conversation, and Stephenson was asked, "Can nothing be done to prevent such awful occurrences?" His reply was that he thought something might be done. "Then," said the other, "the sooner you start the better; for the price of coal-mining now is _pitmen's lives_."

Fifty years since, many of the best pits were so full of the inflammable gas given forth by the coal, that they could not be worked without the greatest danger; and for this reason some were altogether abandoned, The rudest possible methods were adopted of producing light sufficient to enable the pitmen to work by. The phosph.o.r.escence of decayed fish-skins was tried; but this, though safe, was very inefficient. The most common method employed was what was called a steel mill, the notched wheel of which, being made to revolve against a flint, struck a succession of sparks, which scarcely served to do more than make the darkness visible.

A boy carried the apparatus after the miner, working the wheel, and by the imperfect light thus given forth he plied his dangerous trade.

Candles were only used in those parts of the pit where gas was not abundant. Under this rude system not more than one-third of the coal could be worked; and two-thirds were left.

What the workmen, not less than the coal-owners, eagerly desired was, a lamp that should give forth sufficient light, without communicating flame to the inflammable gas which acc.u.mulated in certain parts of the pit.

Something had already been attempted towards the invention of such a lamp by Dr. Clanny, of Sunderland, who, in 1813, contrived an apparatus to which he gave air from the mine through water, by means of bellows. This lamp went out of itself in inflammable gas. It was found, however, too unwieldy to be used by the miners for the purposes of their work, and did not come into general use. A committee of gentlemen was formed to investigate the causes of the explosions, and to devise, if possible, some means of preventing them. At the invitation of that Committee, Sir Humphry Davy, then in the full zenith of his reputation, was requested to turn his attention to the subject. He accordingly visited the collieries near Newcastle on the 24th of August, 1815; and on the 9th of November following, he read before the Royal Society of London his celebrated paper "On the Fire-Damp of Coal Mines, and on Methods of lighting the Mine so as to prevent its explosion."

But a humbler though not less diligent and original thinker had been at work before him, and had already practically solved the problem of the Safety-Lamp. Stephenson was of course well aware of the anxiety which prevailed in the colliery districts as to the invention of a lamp which should give light enough for the miners to work by without exploding the fire-damp. The painful incidents above described only served to quicken his eagerness to master the difficulty.

For several years he had been engaged, in his own rude way, in making experiments with the fire-damp in the Killingworth mine. The pitmen used to expostulate with him on these occasions, believing his experiments to be fraught with danger. One of the sinkers, observing him holding up lighted candles to the windward of the "blower" or fissure from which the inflammable gas escaped, entreated him to desist; but Stephenson's answer was, that "he was busy with a plan by which he hoped to make his experiments useful for preserving men's lives." On these occasions the miners usually got out of the way before he lit the gas.

In 1815, although he was very much occupied with the business of the collieries and the improvement of his locomotive engine, he was also busily engaged in making experiments upon inflammable gas in the Killingworth pit. According to the explanation afterwards given by him, he imagined that if he could construct a lamp with a chimney so arranged as to cause a strong current, it would not fire at the top of the chimney; as the burnt air would ascend with such a velocity as to prevent the inflammable air of the pit from descending towards the flame; and such a lamp, he thought, might be taken into a dangerous atmosphere without risk of exploding.

Such was Stephenson's theory when he proceeded to embody his idea of a miner's safety-lamp in a practical form. In the month of August, 1815, he requested his friend Nicholas Wood, the head viewer, to prepare a drawing of a lamp according to the description which he gave him. After several evenings' careful deliberations, the drawing was made, and shown to several of the head men about the works.

Stephenson proceeded to order a lamp to be made by a Newcastle tinman, according to his plan; and at the same time he directed a gla.s.s to be made for the lamp at the Northumberland Gla.s.s House. Both were received by him from the makers on the 21st October, and the lamp was taken to Killingworth for the purpose of immediate experiment.

"I remember that evening as distinctly as if it had been but yesterday,"

said Robert Stephenson, describing the circ.u.mstances to the author in 1857: "Moodie came to our cottage about dusk, and asked, 'if father had got back yet with the lamp?' 'No.' 'Then I'll wait till he comes,' said Moodie, 'he can't be long now.' In about half-an-hour, in came my father, his face all radiant. He had the lamp with him! It was at once uncovered, and shown to Moodie. Then it was filled with oil, trimmed, and lighted. All was ready, only the head viewer hadn't arrived. 'Run over to Benton for Nichol, Robert,' said my father to me, 'and ask him to come directly; say we're going down the pit to try the lamp.' By this time it was quite dark; and off I ran to bring Nicholas Wood. His house was at Benton, about a mile off. There was a short cut through the Churchyard, but just as I was about to pa.s.s the wicket, I saw what I thought was a white figure moving about amongst the grave-stones. I took it for a ghost! My heart fluttered, and I was in a great fright, but to Wood's house I must get, so I made the circuit of the Churchyard; and when I got round to the other side I looked, and lo! the figure was still there. But what do you think it was? Only the grave-digger, plying his work at that late hour by the light of his lanthorn set upon one of the gravestones! I found Wood at home, and in a few minutes he was mounted and off to my father's. When I got back, I was told they had just left-it was then about eleven-and gone down the shaft to try the lamp in one of the most dangerous parts of the mine."

Arrived at the bottom of the shaft with the lamp, the party directed their steps towards one of the foulest galleries in the pit, where the explosive gas was issuing through a blower in the roof of the mine with a loud hissing noise. By erecting some deal boarding round that part of the gallery into which the gas was escaping, the air was made more foul for the purpose of the experiment. After waiting about an hour, Moodie, whose practical experience of fire-damp in pits was greater than that of either Stephenson or Wood, was requested to go into the place which had thus been made foul; and, having done so, he returned, and told them that the smell of the air was such, that if a lighted candle were now introduced, an explosion must inevitably take place. He cautioned Stephenson as to the danger both to themselves and to the pit, if the gas took fire. But Stephenson declared his confidence in the safety of his lamp, and, having lit the wick, he boldly proceeded with it towards the explosive air. The others, more timid and doubtful, hung back when they came within hearing of the blower; and apprehensive of the danger, they retired into a safe place, out of sight of the lamp, which gradually disappeared with its bearer in the recesses of the mine. {95}

Advancing to the place of danger, and entering within the fouled air, his lighted lamp in hand, Stephenson held it finally out, in the full current of the blower, and within a few inches of its mouth. Thus exposed, the flame of the lamp at first increased, then flickered, and then went out; but there was no explosion of the gas. Returning to his companions, who were still at a distance, he told them what had occurred. Having now acquired somewhat more confidence, they advanced with him to a point from which they could observe him repeat his experiment, but still at a safe distance. They saw that when the lighted lamp was held within the explosive mixture, there was a great flame; the lamp became almost full of fire; and then it smothered out. Again returning to his companions, he relighted the lamp, and repeated the experiment several times with the same result. At length Wood and Moodie ventured to advance close to the fouled part of the pit; and, in making some of the later trials, Mr. Wood himself held up the lighted lamp to the blower.

Before leaving the pit, Stephenson expressed his opinion that by an alteration of the lamp which he then contemplated, he could make it burn better; this was by a change in the slide through which the air was admitted into the lower part, under the flame. After making some experiments on the air collected at the blower, by bladders which were mounted with tubes of various diameters, he satisfied himself that, when the tube was reduced to a certain diameter, the foul air would not pa.s.s through; and he fas.h.i.+oned his slide accordingly, reducing the diameter of the tube until he conceived it was quite safe. In about a fortnight the experiments were repeated, in a place purposely made foul as before; on this occasion a larger number of persons ventured to witness them, and they again proved successful. The lamp was not yet, however, so efficient as the inventor desired. It required, he observed, to be kept very steady when burning in the inflammable gas, otherwise it was liable to go out, in consequence, as he imagined, of the contact of the burnt air (as he then called it), or azotic gas, which lodged round the exterior of the flame. If the lamp was moved horizontally, the azote came in contact with the flame and extinguished it. "It struck me," said he, "that if I put more tubes in, I should discharge the poisonous matter that hung round the flame, by admitting the air to its exterior part."

Although he had then no access to scientific books, nor intercourse with scientific men, nor anything that could a.s.sist him in his investigation, besides his own indefatigable spirit of inquiry, he contrived a rude apparatus by which he tested the explosive properties of the gas and the velocity of current (for this was the direction of his inquiries) necessary to enable the explosive gas to pa.s.s through tubes of different diameters. In making these experiments in his humble cottage at the West Moor, Nicholas Wood and George's son Robert usually acted as his a.s.sistants, and sometimes the gentlemen of the neighbourhood interested in coal-mining attended as spectators.

These experiments were not performed without risk, for on one occasion the experimenting party had nearly blown off the roof of the cottage.

One of these "blows up" was described by Stephenson himself before the Committee on Accidents in Coal Mines, in 1835: "I made several experiments," said he, "as to the velocity required in tubes of different diameters, to prevent explosion from fire-damp. We made the mixtures in all proportions of light carburetted hydrogen with atmospheric air in the receiver, and we found by the experiments that when a current of the most explosive mixture that we could make was forced up a tube 4/10 of an inch in diameter, the necessary current was 9 inches in a second to prevent its coming down that tube. These experiments were repeated several times. We had two or three blows up in making the experiments, by the flame getting down into the receiver, though we had a piece of very fine wire-gauze put at the bottom of the pipe, between the receiver and the pipe through which we were forcing the current. In one of these experiments I was watching the flame in the tube, my son was taking the vibrations of the pendulum of the clock, and Mr. Wood was attending to give me the column of water as I called for it, to keep the current up to a certain point. As I saw the flame descending in the tube I called for more water, and Wood unfortunately turned the c.o.c.k the wrong way, the current ceased, the flame went down the tube, and all our implements were blown to pieces, which at the time we were not very able to replace."

Stephenson followed up those experiments by others of a similar kind, with the view of ascertaining whether ordinary flame would pa.s.s through tubes of a small diameter and with this object he filed off the barrels of several small keys. Placing these together, he held them perpendicularly over a strong flame, and ascertained that it did not pa.s.s upward. This was a further proof to him of the soundness of the course he was pursuing.

In order to correct the defect of his first lamp he resolved to alter it so as to admit the air to the flame by several tubes of reduced diameter, instead of by a single tube. He inferred that a sufficient quant.i.ty of air would thus be introduced into the lamp for the purposes of combustion, while the smallness of the apertures would still prevent the explosive gas pa.s.sing downwards, at the same time that the "burnt air"

(the cause, in his opinion, of the lamp going out) would be more effectually dislodged. He accordingly took the lamp to a tinman in Newcastle, and had it altered so that the air was admitted by three small tubes inserted in the bottom of the lamp, the openings of which were placed on the outside of the burner, instead of having (as in the original lamp) the one tube opening directly under the flame.

This second or altered lamp was tried in the Killingworth pit on the 4th November, and was found to burn better than the first, and to be perfectly safe. But as it did not yet come quite up to the inventor's expectations, he proceeded to contrive a third lamp, in which he proposed to surround the oil vessel with a number of capillary tubes. Then it struck him, that if he cut off the middle of the tubes, or made holes in metal plates, placed at a distance from each other, equal to the length of the tubes, the air would get in better, and the effect in preventing explosion would be the same.

He was encouraged to persevere in the completion of his safety-lamp by the occurrence of several fatal accidents about this time in the Killingworth pit. On the 9th November a boy was killed by a blast in the _A_ pit, at the very place where Stephenson had made the experiments with his first lamp; and, when told of the accident, he observed that if the boy had been provided with his lamp, his life would have been saved. On the 20th November he went over to Newcastle to order his third lamp from a plumber in that town. The plumber referred him to his clerk, whom Stephenson invited to join him at a neighbouring public-house, where they might quietly talk over the matter, and finally settle the plan of the new lamp. They adjourned to the "Newcastle Arms," near the present High Level Bridge, where they had some ale, and a design of the lamp was drawn in pencil upon a half-sheet of foolscap, with a rough specification subjoined. The sketch, when shown to us by Robert Stephenson some years since, still bore the marks of the ale. It was a very rude design, but sufficient to work from. It was immediately placed in the hands of the workmen, finished in the course of a few days, and experimentally tested in the Killingworth pit like the previous lamps, on the 30th November.

At that time neither Stephenson nor Wood had heard of Sir Humphry Davy's experiments nor of the lamp which that gentleman proposed to construct.

An angry controversy afterwards took place as to the respective merits of George Stephenson and Sir Humphry Davy in respect of the invention of the safety-lamp. A committee was formed on both sides, and the facts were stated in various ways. It is perfectly clear, however, that Stephenson had ascertained _the fact_ that flame will not pa.s.s through tubes of a certain diameter-the principle on which the safety-lamp is constructed-before Sir Humphry Davy had formed any definite idea on the subject, or invented the model lamp afterwards exhibited by him before the Royal Society. Stephenson had actually constructed a lamp on such a principle, and proved its safety, before Sir Humphry had communicated his views on the subject to any person; and by the time that the first public intimation had been given of his discovery, Stephenson's second lamp had been constructed and tested in like manner in the Killingworth pit. The _first_ was tried on the 21st October, 1815; the _second_ was tried on the 4th November; but it was not until the 9th November that Sir Humphry Davy presented his first lamp to the public. And by the 30th of the same month, as we have seen, Stephenson had constructed and tested his _third_ safety-lamp.

[Picture: Davy's and Stephenson's Safety Lamps]

Stephenson's theory of the "burnt air" and the "draught" was no doubt wrong; but his lamp was right, and that was the great fact which mainly concerned him. Torricelli did not know the rationale of his tube, nor Otto Gurike that of his air-pump; yet no one thinks of denying them the merit of their inventions on that account. The discoveries of Volta and Galvani were in like manner independent of theory; the greatest discoveries consisting in bringing to light certain grand facts, on which theories are afterwards framed. Our inventor had been pursuing the Baconian method, though he did not think of that, but of inventing a safe lamp, which he knew could only be done through the process of repeated experiment. He experimented upon the fire-damp at the blowers in the mine, and also by means of the apparatus which was blown up in his cottage, as above described by himself. By experiment he distinctly ascertained that the explosion of fire-damp could not pa.s.s through small tubes; and he also did what had not before been done by any inventor-he constructed a lamp on this principle, and repeatedly proved its safety at the risk of his life. At the same time, there is no doubt that it was to Sir Humphry Davy that the merit belonged of having pointed out the true law on which the safety-lamp is constructed.

The subject of this important invention excited so much interest in the northern mining districts, and Stephenson's numerous friends considered his lamp so completely successful-having stood the test of repeated experiments-that they urged him to bring his invention before the Philosophical and Literary Society of Newcastle, of whose apparatus he had availed himself in the course of his experiments on fire-damp. After much persuasion he consented, and a meeting was appointed for the purpose of receiving his explanations, on the evening of the 5th December, 1815.

Stephenson was at that time so diffident in manner and unpractised in speech, that he took with him his friend Nicholas Wood, to act as his interpreter and expositor on the occasion. From eighty to a hundred of the most intelligent members of the society were present at the meeting, when Mr. Wood stood forward to expound the principles on which the lamp had been formed, and to describe the details of its construction.

Several questions were put, to which Mr. Wood proceeded to give replies to the best of his knowledge. But Stephenson, who up to that time had stood behind Wood, screened from notice, observing that the explanations given were not quite correct, could no longer control his reserve, and, standing forward, he proceeded in his strong Northumbrian dialect, to describe the lamp, down to its minutest details. He then produced several bladders full of carburetted hydrogen, which he had collected from the blowers in the Killingworth mine, and proved the safety of his lamp by numerous experiments with the gas, repeated in various ways; his earnest and impressive manner exciting in the minds of his auditors the liveliest interest both in the inventor and his invention.

Shortly after, Sir H. Davy's model lamp was received and exhibited to the coal-miners at Newcastle, on which occasion the observation was made by several gentlemen, "Why, it is the same as Stephenson's!"

Notwithstanding Stephenson's claim to be regarded as the first inventor of the Tube Safety-lamp, his merits do not seem to have been generally recognised; and Sir Humphry Davy carried off the larger share of the _eclat_ which attached to the discovery. What chance had the unknown workman of Killingworth with so distinguished a compet.i.tor? The one was as yet but a colliery engine-wright, scarce raised above the manual-labour cla.s.s, pursuing his experiments in obscurity, with a view only to usefulness; the other was the scientific prodigy of his day, the most brilliant of lecturers, and the most popular of philosophers.

No small indignation was expressed by the friends of Sir Humphry Davy at Stephenson's "presumption" in laying claim to the invention of the safety-lamp. In 1831 Dr. Paris, in his 'Life of Sir Humphry Davy,' thus wrote:-"It will hereafter be scarcely believed that an invention so eminently scientific, and which could never have been derived but from the sterling treasury of science, should have been claimed on behalf of an engine-wright of Killingworth, of the name of Stephenson-a person not even possessing a knowledge of the elements of chemistry."

But Stephenson was far above claiming for himself any invention not his own. He had already accomplished a far greater feat than the making of a safety-lamp-he had constructed a successful locomotive, which was to be seen in daily work on the Killingworth railway. By the improvements he had made in the engine, he might almost be said to have _invented_ it; but no one-not even the philosophers-detected the significance of that wonderful machine. What railways were to become, rested in a great measure with that "engine-wright of Killingworth, of the name of Stephenson," though he was scarcely known as yet beyond the bounds of his own district.

As to the value of the invention of the safety-lamp there could be no doubt; and the colliery owners of Durham and Northumberland, to testify their sense of its importance, determined to present a testimonial to its inventor. The friends of Sir H. Davy met in August, 1816, to take steps for raising a subscription for the purpose. The advertised object of the meeting was to present him with a reward for "the invention of _his_ safety-lamp." To this no objection could be taken; for though the principle on which the safety-lamps of Stephenson and Davy were constructed was the same; and although Stephenson's lamp was, unquestionably, the first successful lamp that had been constructed on such principle, and proved to be efficient,-yet Sir H. Davy did invent a safety-lamp, no doubt quite independent of all that Stephenson had done; and having directed his careful attention to the subject, and elucidated the true theory of explosion of carburetted hydrogen, he was ent.i.tled to all praise and reward for his labours. But when the meeting of coal-owners proposed to raise a subscription for the purpose of presenting Sir H. Davy with a reward for "his invention of _the_ safety-lamp," the case was entirely altered; and Stephenson's friends then proceeded to a.s.sert his claims to be regarded as its first inventor.

Many meetings took place on the subject, and much discussion ensued, the result of which was that a sum of 2000 was presented to Sir Humphry Davy as "the inventor of the safety-lamp;" but, at the same time, a purse of 100 guineas was voted to George Stephenson, in consideration of what he had done in the same direction. This result was, however very unsatisfactory to Stephenson, as well as to his friends, and Mr.

Brandling, of Gosforth, suggested to him that, the subject being now fairly before the public, he should publish a statement of the facts on which his claim was founded.

This was not at all in George's line. He had never appeared in print; and it seemed to him a more formidable thing to write a letter for "the papers" than to invent a safety-lamp or design a locomotive. However, he called to his aid his son Robert, set him down before a sheet of foolscap, and told him to "put down there just what I tell you." The composition of this letter, as we were informed by the writer of it, occupied more evenings than one; and when it was at length finished, after many corrections, and fairly copied out, the father and son set out-the latter dressed in his Sunday's round jacket-to lay the joint production before Mr. Brandling, at Gosforth House. Glancing over the letter, Mr. Brandling said, "George, this will never do." "It is all true, sir," was the reply. "That may be; but it is badly written."

Robert blushed, for he thought the penmans.h.i.+p was called in question, and he had written his best. Mr. Brandling, however, revised the letter, which was shortly after published in the local journals.

Stephenson's friends, fully satisfied of his claims to priority as the inventor of the safety-lamp used in the Killingworth and other collieries, held a public meeting for the purpose of presenting him with a reward "for the valuable service he had thus rendered to mankind." A subscription was immediately commenced with this object, and a committee was formed, consisting of the Earl of Strathmore, C. J. Brandling, and others. The subscriptions, when collected, amounted to 1000. Part of the money was devoted to the purchase of a silver tankard, which was presented to the inventor, together with the balance of the subscription, at a public dinner given in the a.s.sembly Rooms at Newcastle. {105} But what gave Stephenson even greater pleasure than the silver tankard and purse of sovereigns was the gift of a silver watch, purchased by small subscriptions amongst the colliers themselves, and presented by them as a token of their personal esteem and regard for him, as well as of their grat.i.tude for the perseverance and skill with which he had prosecuted his valuable and lifesaving invention to a successful issue.

However great the merits of Stephenson in connexion with the invention of the tube safety-lamp, they cannot be regarded as detracting from the reputation of Sir Humphry Davy. His inquiries into the explosive properties of carburetted hydrogen gas were quite original; and his discovery of the fact that explosion will not pa.s.s through tubes of a certain diameter was made independently of all that Stephenson had done in verification of the same fact. It even appears that Mr. Smithson Tennant and Dr. Wollaston had observed the same fact several years before, though neither Stephenson nor Davy knew it while they were prosecuting their experiments. Sir Humphry Davy's subsequent modification of the tube-lamp, by which, while diminis.h.i.+ng the diameter, he in the same ratio shortened the tubes without danger, and in the form of wire-gauze enveloped the safety-lamp by a multiplicity of tubes, was a beautiful application of the true theory which he had formed upon the subject.

The increased number of accidents which have occurred from explosions in coal-mines since the general introduction of the Davy lamp, have led to considerable doubts as to its safety, and to inquiries as to the means by which it may be further improved; for experience has shown that, under certain circ.u.mstances, the Davy lamp is _not_ safe. Stephenson was himself of opinion that the modification of his own and Sir Humphry Davy's lamp, combining the gla.s.s cylinder with the wire-gauze, was the most secure; at the same time it must be admitted that the Davy and the Geordy lamps alike failed to stand the severe tests to which they were submitted by Dr. Pereira, before the Committee on Accidents in Mines.

Indeed, Dr. Pereira did not hesitate to say, that when exposed to a current of explosive gas the Davy lamp is "decidedly unsafe," and that the experiments by which its safety had been "demonstrated" in the lecture-room had proved entirely "fallacious."

It is worthy of remark, that under circ.u.mstances in which the wire-gauze of the Davy lamp becomes red-hot from the high explosiveness of the gas, the Geordy lamp is extinguished; and we cannot but think that this fact testifies to the decidedly superior safety of the Geordy. An accident occurred in the Oaks colliery Pit at Barnsley, on the 20th August, 1857, which strikingly exemplified the respective qualities of the lamps. A sudden outburst of gas took place from the floor of the mine, along a distance of fifty yards. Fortunately the men working in the pit at the time were all supplied with safety-lamps-the hewers with Stephenson's, and the hurriers with Davy's. Upon this occasion, the whole of the Stephenson's lamps, over a s.p.a.ce of five hundred yards, were extinguished almost instantaneously; whereas the Davy lamps were filled with fire, and became red-hot-so much so, that several of the men using them had their hands burnt by the gauze. Had a strong current of air been blowing through the gallery at the time, an explosion would most probably have taken place-an accident which, it will be observed, could not, under such circ.u.mstances, occur from the use of the Geordy, which is immediately extinguished as soon as the air becomes explosive. {107}

Nicholas Wood, a good judge, has said of the two inventions, "Priority has been claimed for each of them-I believe the inventions to be parallel. By different roads they both arrived at the same result.

Stephenson's is the superior lamp. Davy's is safe-Stephenson's is safer."

When the question of priority was under discussion at the studio of Mr.

Lough, the sculptor, in 1857, Sir Matthew White Ridley asked Robert Stephenson, who was present, for his opinion on the subject. His answer was, "I am not exactly the person to give an unbia.s.sed opinion; but, as you ask me frankly, I will as frankly say, that if George Stephenson had never lived, Sir Humphry Davy could and most probably would have invented the safety-lamp; but again, if Sir Humphry Davy had never lived, George Stephenson certainly would have invented the safety-lamp, as I believe he did, independent of all that Sir Humphry Davy had ever done in the matter."

[Picture: West Moor Pit, Killingworth]

CHAPTER VII.

GEORGE STEPHENSON'S FURTHER IMPROVEMENTS IN THE LOCOMOTIVE-THE HETTON RAILWAY-ROBERT STEPHENSON AS VIEWER'S APPRENTICE AND STUDENT.

Stephenson's experiments on fire-damp, and his labours in connexion with the invention of the safety-lamp, occupied but a small portion of his time, which was necessarily devoted for the most part to the ordinary business of the colliery. From the day of his appointment as engine-wright, one of the subjects which particularly occupied his attention was the best practical method of winning and raising the coal.