Stephenson 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 of 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 been saved.

The third safety lamp, as finally designed by Stephenson, was in the hands of the manufacturer on the 24th of November, before he had heard of Sir Humphry Davy's experiments, or of the lamp which that gentleman proposed to construct. And this third lamp was finished, and tried in the Killingworth pit, on the 30th of the same month. On the 5th of December, Stephenson exhibited it before the Literary and Philosophical Society of Newcastle; and shortly after it came into practical use in the Killingworth collieries. To this day it is in regular use there, under the name of the "Geordy Lamp," as contradistinguished from the "Davy;" and the Killingworth pitmen have expressed to the writer their decided preference for the "Geordy." It is certainly a strong testimony in its favour, that no accident is known to have arisen from its use, since it was first introduced into the Killingworth mines. With the addition of the wire-gauze over the glass cylinder, Mr. Stephenson expressed his conviction, before the committee above referred to, that, so altered, his lamp is the safest for use, and superior to every other.*

* Report on Accidents in Coal Mines, 1835, p. 103.

CHAPTER XI.

CONTROVERSY AS TO THE INVENTION OF THE SAFETY LAMP.

ALTHOUGH the first safety lamp, adapted for practical use in the every-day work of coal-mining, was contrived by George Stephenson, the name of Sir Humphry Davy, as most readers are aware, has been generally identified with the invention. But a Committee of the House of Commons, which sat in 1835, after making a careful and detailed inquiry into the whole subject, distinctly stated that "The principles of its construction appear to have been practically know to Clanny and Stephenson, previously to the period when Davy brought his powerful mind to bear upon the subject." * Not only, however, were the principles of its construction known to Stephenson, but he actually made a Lamp, the safety of which he demonstrated by repeated experiments, several months before Sir Humphry Davy had produced his Miner's Lamp, or published his views upon the subject.

Dr. Clanny had also constructed a Safety Lamp, before Stephenson had made the attempt, after a plan first suggested and tried by Humboldt. It was, to insulate the air within the lamp from the foul air in the mine, by means of water, and to keep up the supply of atmospheric air by the action of bellows. But this lamp, though safe, was found impracticable, and consequently was not adopted. What was wanted was a lamp that the miners could easily carry about with them; that would give light enough to enable them to work by in dangerous places, and yet be safe. And such a lamp Stephenson was unquestionably the first to invent, construct, and prove. It will be observed, from what has been stated, that the plan which Stephenson adopted was to supply air to the flame of the lamp by means of small tubes. It afterwards

* Report on Accidents in Mines, Session 1835, p. vii. (Parliamentary Paper, 603.)

appeared, from a paper published by Sir Humphry Davy in the following year,* that this was the idea which he contemplated embodying in his first lamp. But Stephenson had already ascertained the same fact, and confirmed it by repeated experiments with the two Safety Lamps which were constructed for him after the designs which he furnished. It is true, his theory of the "burnt air," and of "the draught," was wrong; but his lamp was right. Torricelli did not know the rationale of his Tube, nor Otto Gürike that of his Airpump; 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. Mr. Stephenson pursued the Baconian method, though he did not think of that, but of inventing a safe lamp, which he knew could only be done through a 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 pass through small tubes; and he also effected 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. In a letter published by Mr. Stephenson in the Philosophical Magazine f-the editor of which had given expression to the opinion that his attempts at safety tubes and apertures had been borrowed from what he heard of Sir Humphry Davy's researches,—he challenged the editor to bring the evidence of facts and dates before the public, before venturing to dispute his veracity. "If fire-damp," said he, 66 were admitted to the flame of a lamp through a small tube, -that it would be consumed by combustion, and that explosion would not pass and communicate with the external gas, was the idea I had embraced as the principle on which a safety lamp might be constructed, and this I stated to several persons long before Sir H. Davy came into this part of the country. The plan of such a lamp was seen by several, and the lamp itself was in the hands of the manufacturer during the time he was here; at which period it is not pretended he *Philosophical Transactions for 1816, part i. p. 11. † Philosophical Magazine for March, 1817.

had formed any correct idea upon which he intended to act. . . That I pursued the principle thus discovered and applied, and constructed a lamp with three tubes, and one with small perforations, without knowing that Sir Humphry Davy had adopted the same idea, and without receiving any hint of his experiments, is what I solemnly assert."

Indeed it is perfectly clear, from the dates at which the results of Sir Humphry Davy's experiments with fire-damp were published, that it was simply impossible for Mr. Stephenson to have borrowed any of his ideas or plans. The latter, it will be remembered, had prepared the plan of his first safety lamp as early as August, 1815, at which time Sir Humphry Davy had not given much consideration to the subject, nor formed any definite ideas upon it. On the 29th of September following, Davy wrote to the Rev. Mr. Hodgson, requesting a supply of fire-damp from a blower, and informing him, at the same time, that "he had thought a good deal on the prevention of explosions from fire-damp, and entertained strong hopes of being able to effect something satisfactory on the subject." * It is obvious, then, that at that date Sir Humphry had not discovered the tube principle, nor applied it in the invention of a lamp. Sir H. Davy, shortly after this time, is found in correspondence with the Rev. Mr. Hodgson as to the principle afterwards enunciated by him, that explosion would not pass down small tubes; and on the 19th of October he wrote a private letter, communicating his views on the subject; but Mr. Hodgson regarded this letter as strictly confidential, and did not in any way communicate it to the public.

Mr. Stephenson, it will be remembered, placed the plan of his lamp in the hands of the Newcastle tinman in the beginning of October; and it was made and delivered to him on the 21st of October, after which it was tested at the blower in the Killingworth pit, on the evening of the same day. Up to this time nothing was known of the nature or results of Sir H. Davy's experiments. But on the 31st of October Davy communicated the fact which he had now discovered to the Rev. Dr. Gray, then Rector of Bishop Wearmouth (afterwards Bishop of Bristol), in a communication intended to be

*Letter published by the Rev. Mr. Hodgson in support of Sir H. Davy's claims, in the Newcastle Courant of February 1st, 1817.

private, but which was inadvertently read at a public meeting of coal-miners held at Newcastle on the 3d of November following. In that letter he stated,—" 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 not less than one eighth of an inch, or even a larger tube, if there is a mechanical force urging the gas through the tube." This was the first public intimation of the result of Sir H. Davy's investigations; and it has been stated as probable that the information was conveyed to Mr. Stephenson by some of his friends who might have attended the meeting. Supposing this to be so, it contained nothing which he had not already verified by repeated experiments. The fact that explosion would not pass through small tubes was by this time perfectly well known to him. He had been continuing his experiments during the end of October and the beginning of November; his second and improved lamp, constructed on this very principle, was already completed, and it was actually tried in the Killingworth mine on the 4th of November, the very day following the meeting at which Sir Humphry Davy's discovery was first announced. Whereas the Tube Safety Lamp, which the latter had constructed on the principle above stated, was not presented to the Royal Society until the 9th of November following. Thus, Mr. Stephenson had invented and tested two several tube lamps before Sir Humphry Davy had presented his first lamp to the public.

The subject of this important invention was exciting so much interest in the northern mining districts, and Mr. 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 some of whose apparatus he had availed himself in the course of his experiments on fire-damp. After much persuasion, he consented to do so; and a meeting was appointed for the purpose of receiving his explanations, on the evening of the 5th of December, 1815. Mr. Stephenson was at that time so diffi* Paris's Life of Davy, 4to ed., p. 314.