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 accumulated 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 glass to be made for the lamp at the Northumberland Glass 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 circumstances 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 pass 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.”