CHAP. VI.

EXPLOSIONS OF FIRE-DAMP.

77

cident occurred in the same pit in the year following, by which twenty-two men and boys perished.

It was natural that George Stephenson, when appointed to the responsible office of colliery engine wright, should devote his attention to the cause of these deplorable accidents, and to the means by which they might if possible be prevented. His daily occupation led him to think much and deeply on the subject. As the engineer of a colliery so extensive as that of Killingworth, where there were nearly 160 miles of gallery excavation, and in which he personally superintended the formation of inclined planes for the conveyance of the coal to the pit entrance, he was necessarily very often underground, and brought face to face with the dangers of fire-damp. From fissures in the roofs of the galleries, carburetted hydrogen gas was constantly flowing; in some of the more dangerous places it might be heard escaping from the crevices of the coal with a hissing noise. Ventilation, firing, and all conceivable modes of drawing out the foul air had been adopted, and the more dangerous parts of the galleries were built up. Still the danger could not be wholly prevented. The miners must necessarily guide their steps. through the extensive underground pathways with lighted lamps or candles, the naked flame of which, coming in contact with the inflammable air, daily exposed them and their fellow-workers in the pit to the risk of death in one of its most dreadful forms.

One day, in the year 1814, a workman hurried into Mr. Stephenson's cottage with the startling information that the deepest main of the colliery was on fire! He immediately hastened to the pit-mouth, about a hundred yards off, whither the women and children of the colliery were fast running, with wildness and terror depicted in every face. In an energetic voice Stephenson ordered the engineman to lower him down the shaft in the corve. There was danger, it might be death, before him,—but he must go. As those about the pit-mouth saw him descend rapidly out of sight, and heard from the gloomy depths of the shaft the mingled cries of despair and agony rising from the workpeople

78

STEPHENSON'S INTREPID CONDUCT.

CHAP. VI.

below, they gazed on the heroic man with breathless amaze

ment.

He was soon at the bottom, and in the midst of his workmen, who were paralysed at the danger which threatened the lives of all in the pit. Leaping from the corve on its touching the ground, he called out "Stand back! Are there six men among you who have courage enough to follow me? If so, come, and we will put the fire out." The Killingworth men always had the most perfect confidence in George Stephenson, and instantly they volunteered to follow him. Silence succeeded to the frantic tumult of the previous minute, and the men set to work. In every mine, bricks, mortar, and tools enough are at hand, and by Stephenson's direction materials were forthwith carried to the required spot, where, in a very short time, the 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 Mr. Stephenson was related to the writer, near the pit-mouth, by one of the men, Kit Heppel, who had been an eye-witness to it, and helped to build up the brick wall by which the fire was stayed, though several workmen were suffocated in the pit. Heppel relates that, when down the pit some days after, seeking out the dead bodies, the cause of the accident was the subject of some conversation between himself and Stephenson, and Heppel then asked him, "Can nothing be done to prevent such awful occurrences?" Stephenson replied that he thought something might be done. Then," said Heppel, "the sooner you start the better; for the price of coal-mining now is pitmen's lives."

66

The chief object to be attained was, to devise a lamp that would burn and give forth sufficient light to guide the miner in his underground labours, without communicating flame to the inflammable gas which accumulated in certain parts of the pit. Something had already been attempted towards the invention of a colliery lamp by Dr. Clanny, of Sunder

CHAP. VI.

MEDITATES A SAFETY-LAMP.

79

land, 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. A committee of gentlemen was formed at Sunderland 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 at the close of that year, on the 9th of November, 1815, he read his celebrated paper "On the Fire-Damp of Coal Mines, and on Methods of lighting the Mine so as to prevent its Explosion," before the Royal Society of London.

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' work without exploding the fire-damp. The painful incidents above described only served to quicken his eagerness to master the difficulty. Let the reader bear in mind the comparative obscurity of Stephenson's position, for he was as yet but one step removed from the grade of a manual labourer,—the meagreness of his scientific knowledge, all of which he had himself gathered bit by bit during his leisure moments, which were but few,—his almost entire lack of teachers excepting his own keen and observant eye and his shrewd and penetrating judgment: let these things be remembered, and the invention of the Geordy Safety-Lamp will be regarded as an achievement of the highest merit.

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

80

HIS EXPERIMENTS WITH FIRE-DAMP.

CHAP. VI.

on these occasions, believing that the experiments were fraught with danger. One of the sinkers called M'Crie, 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 could 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 with the improvements in his new locomotive engine, he was also busily engaged in making experiments on inflammable gas in the Killingworth pit. As he himself afterwards related to the Committee of the House of Commons which sat on the subject of Accidents in Mines in 1835, the nature and object of those experiments, we cannot do better than cite his own words :

"I will give the Committee," said he, "my idea mechanically, because I knew nothing of chemistry at the time. Seeing the gas lighted up, and observing the velocity with which the flame passed along the roof, my attention was drawn to the contriving of a lamp, seeing it required a given time to pass over a given distance. My idea of making a lamp was entirely on mechanical principles; and I think I shall be found quite correct in my views, from mechanical reasoning. I knew well that the heated air from the fire drove round a smoke-jack, and that caused me to know that I could have a power from it. I also knew very well that a steam-engine chimney was built for the purpose of causing a strong current of air through the fire. Having these facts before me, and knowing the properties of heated air, I amused myself with lighting one of the blowers in the neighbourhood of where I had to erect machinery. I had it on fire; the volume of flame was coming out the size of my two hands, but was not so ge but that I could approach close to it. Holding my ndle to the windward of the flame, I observed that it

CHAP. VI.

HIS FIRST SAFETY-LAMP.

81

changed its colour. I then got two candles, and again placed them to the windward of the flame: it changed colour still more, and became duller. I got a number of candles, and placing them all to the windward, the blower ceased to burn. This then gave me the idea, that if I could construct my lamp so as, with a chimney at the top, to cause a current, it would never fire at the top of the chimney; and by seeing the velocity with which the ignited fire-damp passed along the roof, I considered that, if I could produce a current through tubes in a lamp equal to the current that I saw passing along the roof, I should make a lamp that could be taken into an explosive mixture without exploding externally."

Such was Mr. 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 Mr. Nicholas Wood, the head viewer of the colliery, to prepare a drawing of a lamp, according to the description which he gave him. After several evenings' careful deliberations, the drawing was prepared, and it was shown to several of the head men about the works. 66 My first lamp," said Mr. Stephenson, describing it to the Committee above referred to, "had a chimney at the top of the lamp, and a tube at the bottom, to admit the atmospheric air, or fire-damp and air, to feed the burner or combustion of the lamp. I was not aware of the precise quantity required to feed the combustion; but to know what quantity was necessary, I had a slide at the bottom of the first tube in my lamp, to admit such a quantity of air as might eventually be found necessary to keep up the combustion." Stephenson then, accompanied by his friend Wood, the head viewer, went to Newcastle and ordered a lamp to be made according to the prepared plan, by Messrs. Hogg, tinmen, at the head of the Side—a wellknown street in Newcastle. At the same time, they ordered a glass to be made for the lamp, at the Northumberland Glass House, in the same town. This lamp was received from the makers on the 21st of October, and

G