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Volume 36 (XXXVI), 1886-1887, published 1887
Remarks on a further discharge of lightning at the West Thornley Colliery, near Tow Law, on October 21st, 1886.
By Henry White.
The following remarks on another discharge of lightning at the West Thornley Colliery, afford a further confirmation of lightning going down the pit, and more particularly as to its power of travelling a considerable distance in-bye, notwithstanding the fact of a lightning conductor having been attached to the chimney, after it was damaged on December 11th, 1883. See Vol. XXXIII., page 81.
The chimney and conductor are now about 76 feet high, 25 feet higher than the pulleys, and only 68 feet distant from them; bearing out the theory that the area or space protected by a conductor is in the form of a cone, whose base is equal to its height.
On the Thursday afternoon, October 21, 1886, there was a very severe thunderstorm, with much rain, and the lightning went down the pit twice in about five minutes, as is shown by the following evidence :—
John Batey, onsetter, who was at the pit bottom, says that when standing on the flat sheets, about 4 feet from the cage on the east side of pit, the pit bottom was lighted up by a flash of lightning, which appeared to have come down the east side rope (cage standing at the bottom at the time), or the one furthest from the steam and other pipes.
Robert Chambers, who was about 12 yards from the pit bottom, and shoving an empty tub along the shaft siding, says he would be about 18 inches from the steam and water pipes when he saw the lightning; he was struck on the elbow, and felt a pain or numbness in it for the rest of that day and the following one.
W. R. Teasdale, the hauling engineman (40 yards from pit bottom), was running the sett in-bye when his engine house was lighted up, and he heard a noise like a pistol shot, and thought some part of his engine had broken. After the sett had got in-bye, and when examining the engine which was then standing, he saw another flash about five minutes after the first.
Robert Simpson, the landing lad in the top coal landing, about 660 yards from the shaft bottom, says when in the lauding the place was lighted up, apparently on the tail rope side, and he heard a fizzing or crackling like a squib. About five minutes afterwards he and the driver lad saw this repeated.
A few months after the previous discharge, December 11, 1883, Mr. Heaviside, of the Post Office Telegraph Department, and a friend of his, made a very careful examination of the place and its surroundings, and wrote Mr. Heaviside as follows
7, Grafton Road. Whitley,
Newcastle-On-Tyne,
April 4th, 1884.
Henry White, Esq., Tow Law.
Dear Sir,
Referring to our examination of the scene of the lightning discharge at West Thornley, on December 11th, 1883, a probable explanation of the phenomenon is as follows :—
The highly electrified storm cloud hurrying violently along with the wind from the W.N.W., would pass over the hill to the W.N.W. of West Thornley Colliery, and then suddenly drive over the colliery, inducing, in the mass of metallic conductors (steam-pipes, boilers, and ropes, etc.), good and bad, concentrated at that point, electricity of the opposite kind to its own, and owing to the convenience of discharge at that particular place, due to the presence of the colliery plant in general providing better conductors to earth than other objects in the immediate neighbourhood, it would strike every point that would assist in the discharge, as it were, everything in favour of a charge and discharge was focussed at that particular point. The first object in the storm cloud's path was the chimney, which, being a refractory conductor, was rent and fractured, until the current of high electro-motive force reached a point 15 feet from the bottom of the chimney, where a metallic connection was met, made by means of an iron stay attached to a steam-pipe from the boilers for the support of the steam-pipe. The stay, the steam-pipe, and the gear attached, formed part of a continuous good conductor, from the surface to the bottom of the pit, where, probably, the largest portion of the electricity would be discharged; but inducing in everything within range of its path electricity of the opposite sign, from which sparks, or luminous discharge, with the ordinary accompaniments of the ozone smell, described as vapour, and noise would be given off, hence the discharge between the rapper handle and the steam-pipes at the bottom of the pit.
Had the pulleys, etc., been the first objects in the path of the storm, i.e., had the storm been coming the opposite way, probably the chimney would not have suffered, as the ropes, pulleys, and gear attached are much better conductors than the chimney, and might have sufficed to effect the discharge. But one cannot be dogmatic in such matters of opinion, because lightning discharges appear to be capricious, due to our imperfect knowledge of the subject.
In such accidents it would be interesting to know, as in this case, whether the injury is in the direction from whence the storm comes, and also whether accompanied by rain or other natural effects.
Yours very truly,
A. W. Heaviside.
