Taken from The History, Topography, and Directory of the County Palatine of Durham by Francis Whellan. Second edition published in 1894.

The collier in descending to his work seldom needs to carry a light through the shaft. A few seconds are sufficient to land him at the bottom, either in the dense gloom of the pit eye, rendered barely visible by a candle or a safety-lamp, or, according to the circumstances of the colliery in a busy scene of activity, well lighted by oil lamps, gas, or even by electricity. Here he will light up, and, after a little delay in order to accustom the eye to the darkness, proceed on his inward way.

Previous to the introduction of the safety-lamp, tallow candles were commonly used by the miners for lighting them at their work. These were from twenty to twenty-five to the pound, but for fiery collieries were much thinner. It was the regular practice to test the presence of fire-damp in the working stalls and in the wastes by the appearances of the flame of a candle; and skilful, steady-handed pitmen acquired such readiness in thus trying the gas, that they could almost play with it when standing within a hair’sbreadth of destruction. The slim candle is neatly trimmed, and held out shaded by one hand, so that the top of the flame can be more clearly watched. On being advanced gradually upward in a place where fire-damp is lodged, the flame is seen to elongate and become blue, more or less pure according to the nature of the gases present. If the carburetted hydrogen be much mingled with carbonic acid, nitrogen, &c., the cap of the flame will show a grey or brown tint, and such variations will be frequent in the mingled impurities of the return air courses. As some varieties of fiery gas are "quick" in comparison with others, it needs a cool head and unswerving hand to lower the candle again with the requisite stillness when once it had shown too dangerous a cap. It seldom happens that the candle is used for this purpose unless to test the presence of the enemy in places capable of storing only a small quantity. Various substitutes for the old methods of lighting were tried before the close of the last century. The sun’s rays reflected from a mirror were utilised to some extent, but were adequate only for short distances. The steel mill was then invented by Spedding of Whitehaven, which consisted of a disc with periphery of steel, made to rotate rapidly against a sharp flint, and by this means giving a succession of sparks which yielded a feeble light.

It would require too much space to describe the many attempts that have been made, and the numerous contrivances that have been proposed, in order to provide a safer light for the miners; a few of the safety-lamps, however, which have come into extensive use may be named. Dr. Clanny, a medical gentleman of Sunderland, constructed his first lamp in the year 1811. The year following a number of serious explosions occurred in the County of Durham, which led to the formation of a Society for the Prevention of Accidents in Coal-Mines, at whose meetings in Sunderland, in 1813, Dr. Clanny exhibited his Limp, which was intended to give light in an explosive atmosphere. In October and November 1815 this lamp was tried in a fiery pit, whilst that of Sir Humphrey Davy is stated to have been first tested in practice only on the 1st of January 1816. But although thus early in the field, Dr. Clanny afterwards judiciously modified his lamp in applying to a part of it the invention of Davy.

Sir Humphrey first visited some of the collieries in 1815, and after an elaborate series of investigations perfected the lamp which has proved so great a boon to the mining community. From successive inquiries the fact was established, that flame cannot be passed except under pressure through a wire gauze, containing from six to eight hundred holes to the square inch, and that hence the explosive mixture might ignite inside the gauze without communicating the flame to the gas outside of it. In the long series of years that have elapsed since the first safety-lamps were used in the northern coalfields few accidents have been traced to the lamp itself, and many of the alleged cases are doubtful. Its thorough efficacy has been daily proved; and it is like the effect of magic to pass with the safety-lamp in hand in the midst of an atmosphere whose deadly power would dash you to pieces if but a single wire were awry in the gauze. Indeed the measure of the forces let loose by these explosions is simply incalculable. Timbering is blown out, the roof caves in, iron tram-roads are torn up, and the rails bent into every conceivable form; tubs (small waggons) are smashed to Pieces and blown long distances, stoppings and air crossings are blown down, and ventilation itself destroyed. In such catastrophes human and animal life are quickly despatched, and none are left to tell the tale as to where and how the death-fiend broke loose. Abundance of warning is, however, given by this lamp; and as the volume of gas increases, the flame, at first elongated by a blue cap, flashes into an explosion within the lamp more or less fierce, according to the nature of the air. When the carburetted hydrogen is mixed with common air in the ratios of from one to six parts to one to twelve parts it is high ly explosive, whilst below and above that proportion it burns quietly. But if the fire-damp burn in it until the gauze becomes red-hot, it is time to withdraw the lamp steadily from the place, or to extinguish it either by dipping it in water or by drawing down the wick with the pricker and suffocating the gas flame. The chief objection to the Davy lamp is the small amount of light it gives out, which leads the colliers who are paid by quantity to substitute, when they think they are safe, the lighted candle or the lamp with the gauze removed. The numerous accidents through this cause have led to a number of modifications of the original lamp, some for obtaining more light, and others of locking the gauze of the lamp. It is now proved that the Davy lamp pure and simple cannot be relied upon as one of safety to the workmen, but as a means of proving the presence of fire-damp it is hardly, if at all, excelled; yet the lamp, when placed within a lantern, becomes one of the safest known, and to the credit of a North country viewer it will be of interest to place the following facts on record. About the year 1865, the late Mr. Richard Heckels, at that time chief viewer of the Earl of Durham’s Houghton collieries, instituted a series of experiments with a view of improving the Davy lamp, knowing that the Davy lamp in common use could not be carried about with safety where fire-damp existed, and after many experiments he found that the lamp was rendered perfectly safe by being placed in a workman’s tin can. He then had lanterns made of this shape, and it is from this that the Davy, when placed within the lantern, is called the "tin can lamp." Mr. Heck els was also the author of the first great improvement in Sir Humphrey’s lamp. When viewer at the Thornley and Ludworth collieries, he discovered that flame would pass through the wick tube into the oil reservoir when the oil was below the level of the spout, and if the plug happened to be out, would continue its course upward, and explode the inflammable gas. The men, not suspecting the danger, were in the habit of assisting each other with oil, the plugs being withdrawn for the purpose. Mr. Heckels, being unable to trace the source of some explosion, began to test the lamp under varying conditions, and in the proof just named solved the cause of the accident. This eminent engineer was born at Earsdon, Northumberland, in 1818, and died at Sunderland, February 22, 1877.

Many other lamps have been brought forward, many of which have successfully withstood the severe tests to which they have been subjected; but it is worthy of notice that whilst at present a great diversity of opinion exists amongst our colliery managers as to which is the best safety-lamp, a very large majority adhere to the Davy as being the most sensitive lamp by which to test the presence of fire-damp.

In no department of coal-mining is strict discipline and attention to orders so momentous as in the question of lighting. The misplaced confidence which is the result either of ignorance, of hardihood, or of long impunity, has led to the sacrifice of thousands of colliers, the innocent often suffering with the guilty; and among the most useful of the innovations of the governmental inspection is that of giving authority to the code of rules to be established in every pit, and thus protecting the majority of the men, the steadier workers, against the few reckless ones, who, choosing to act for themselves, steal in secret the luxury of their pipe or some extra light at the risk of their own and their comrades’ lives.