The danger from inflammable gases was known and appreciated very early in the history of mining. But it was long thought to be an unavoidable danger. Light must be had or no work could be done, and the only light that could be obtained was from the flame produced by combustion. Candles were commonly used. They were stuck into a ball of clay and fastened to the sides of the working places at the most advantageous points. The bituminous mines of England were peculiarly prolific of inflammable gases; accidents were almost of daily occurrence. On the 25th of May, 1812, a great disaster occurred at Felling Colliery, near Newcastle, in which eighty-nine persons lost their lives by explosion of fire damp, and public attention and the public conscience were directed to the matter of safety in mines more intensely than ever. Sir Humphrey Davy was then in the zenith of his fame. In April, 1815, he returned to London after a triumphal tour through France and Italy, in which his progress had been marked by a series of brilliant experiments. He had no sooner reached home than he was asked by Mr. Buddie, a well-known colliery owner of that day, to turn his attention toward improved methods of lighting the mines. Specimens of the dangerous gas were sent to him from Newcastle, and he experimented with them. He found that the flame from them would not pass through a small tube, nor through a set of small tubes standing side by side. He found also that the length of the tube was immaterial. He therefore shortened them until they were mere sections, until his set of parallel tubes became simply wire gauze. The proper proportion between the substance of the wire and the size of the aperture was found to be twenty-eight wires to the linear inch, and seven hundred and eighty-four apertures to the square inch, a proportion that is still in use. This wire gauze was then made into the form of a cylindrical tube about six inches long and one and one half inches in diameter, with a flat gauze top. To the bottom of this tube was fastened a small cylindrical oil vessel, and to the top a ring handle. The wick extended up from the oil vessel inside the tube.