CHAP. XL

HIS IDEAS NOT BILEID HI CATT 115 letter published by Mr. Stephenson in the Philosophical Magazine*—the editor of which had giver expression to the opinion that his attempts at safety robes and apertures had been borrowed from what he beard of Sir Hunphy INTT'S researches,— he challenged the eisor so bring the evidence of facts and dates before the pulle, before venturing to die pute his veracity. "If fire-damp," said be, were admitted to the flame of a lamp through a small sube,—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 oventry. 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 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 in

* Philosophical Magazine for March, 1817.

forming 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 private f, but which was inadvertently read at a public meeting of coal-miners held at Newcastle on the 3rd 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 4th of an inch, or even

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

Paris's Life of Davy, 4to ed., p. 314.

CHAP. XI.]

SIR H. DAVY'S INVESTIGATIONS.

117 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 diffident in manner and unpractised in speech, that he took with him his friend Mr. 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.

66

Sir Humphry Davy had not, at this time, sent down to his friends in Newcastle a specimen of his lamp; but on the 14th of December, he wrote thus to the Rev. Dr. Gray :—“I trust I shall be able in a very few days to send you a model of a lanthorn nearly as simple as a common glass lanthorn, and which cannot communicate explosion to the fire-damp." He further explained that the lamp was to be constructed on the principle that "the fire-damp will not explode in tubes or feeders of a certain small diameter," and that "the ingress into, and egress of air from, this lanthorn, is through such small tubes or feeders."* 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 Mr. Stephenson's claim to be regarded as *Paris's Life of Davy, 4to ed., pp. 314, 315.

CHAP. XI.]

COMPARISON WITH SIR H. DAVY.

119

the first inventor of the Tube Safety Lamp, his merits do not seem to have been recognised at the time beyond the limits of his own district. Sir Humphry Davy carried off all the éclat which attached to the discovery. What chance had the unknown workman of Killingworth with so distinguished a competitor? The one was as yet but a colliery engine-wright, scarce raised above the manual labour class, without chemical knowledge or literary culture, pursuing his experiments in obscurity, with a view only to usefulness; the other was the scientific prodigy of his day, the pet of the Royal Society, the favourite of princes, the most brilliant of lecturers, and the most popular of philosophers. Davy had not in him much of the patient plodding of the experimentalist, but he divined science as if by inspiration. He had the temperament and genius of a poet, which blazed forth in dazzling eloquence, winning for him alike the admiration of fashionable ladies and of learned philosophers, and making his lectures and experiments "the rage" of the hour. The press blazoned forth his discoveries and enhanced his magnificent reputation; and when he presented his Davy Lamp to the world, it was regarded as but one of the many brilliant achievements which his grand and original genius had conquered.

But George Stephenson, though a less brilliant, was a no less useful and original worker; and when the merit of inventing the safety lamp became the subject of discussion, it was only reasonable and proper that his claims should be fairly considered. He had risked his life in testing the safety of his lamp, before Sir Humphry Davy had even formed a definite opinion on the subject. And though the theory on which Stephenson constructed his lamp was erroneous, he had proved it to be a safety lamp to all intents and purposes. He had discovered the lamp, though not its rationale. Such being the case, he calmly yet firmly asserted his claims as its inventor. No small indignation was expressed by the friends of Sir