It having come to the notice of several members of the Institute that lightning had been stated to have entered Tanfield Moor Colliery on Monday, July 12th, 1880, and traversed the workings in several directions, Mr. William Joicey kindly gave them permission to examine the witnesses of the occurrence and the workings of the colliery so that a complete and accurate report could be drawn up of the circumstance ; and, on the 30th July, 1880, Mr. C. Berkley, Mr. J. B. Simpson, Mr. W. H. Hedley, and the Secretary went out to the colliery and were met by Mr. W. Joicey, one of the owners, Mr. Pringle the viewer, and Mr. Arkless the resident viewer; and the following statement is a record of the information then obtained :—

The top of the working shaft at this Colliery is 36 fathoms from the Shield Row Seam, and Plate VIII. shows the arrangements at the bottom of the shaft; Fig. 1, Plate IX., shows the plan of the workings; and Fig. 2 shows a section through the north incline way and the south engine way; both plates show the position of the different witnesses at the time of the appearance of the lightning ; and Plate X. shows the position of the pipes, ropes, and signal wires in the shaft, it will be seen by these plans that the Incline Bank leads northwards from the working shaft and ultimately reaches the day by a drift at X, and a little to the south of this is an upcast shaft. The Engine way leads south from the working shaft, and goes in-bye to the goaf at Y. It will be remarked that between this goaf and the working shaft there are two down-cast shafts, one of which is to the south of the furthest witness at this part of the pit. From what can be gathered, the lightning passed down the working shaft and struck the flat-sheets and then divided itself into two parts, one of which went north up the Incline way and probably passed out to the day at X, where it is supposed to have left traces of its exit in marks upon a bank of rubbish near by. The other part went south, along the Engine way, but after passing the point B, where it was noticed, its further course is not known; the thill of the seam is composed of soft sagger and the roof of strong post, both of which would offer great obstruction to the absorption of the electric fluid, and the probability is, that this portion of the fluid had been dissipated in the goaf, or had forced an exit by way of the down-cast shaft, No. 2.

The following evidence was taken :—

Joseph Kirtley, back overman, said, that on Monday, the 12th July, about 3 o'clock P.M., he was on the north side of the shaft, about six yards from it. A light, distinct but not very bright, fell and struck the flat-sheets, and split up into several lights like a lot of lighted matches. He could only see the light for a moment among the tub wheels. It struck the puller-out William Watson, who said, "Man, something struck me on the arm ;" he complained that his arm was numb. The onsetter, James Offord; H. McGie and Wilfred Reay, drivers; and John Burdis, who minds the drags, also saw it. Watson told Kirtley afterwards that when he got home his left arm from the wrist to the elbow was quite yellow. Kirtley said, "That's lightning;" and the onsetter said the same. A heavy peal of thunder was heard very distinctly almost at the same moment. No injury was done either in the shaft or on the road where the lightning was said to have passed. He could liken it to nothing better than a box of matches all struck at once.

James Offord, onsetter, said that on Monday, the 12th of July, about a quarter or half-past three, he was at the shaft bottom on the north side. He had just sent the west cage away and had his back to the pit, perhaps two or three yards from it, taking hold of a tub to be ready to set it on in the next cage, when he heard a crack like the report of a small pistol, and saw a light close to his feet. He was on the north side of the pit. William Watson was standing on the opposite side of the pit, and saw the fire strike the flat-sheets and make its way towards the North Incline. He also felt another part go past him to the south. He heard a heavy peal of thunder almost immediately on the light being seen ; did not recollect ever hearing such a heavy peal ; he never noticed lightning come down the pit before. The slides in the pit are all of wood. There are two sets of steam pipes; they come from bank under the heap-stead and down the pit, and go into the south side just over the head of the puller-out.

William Watson, 24 years of age, puller-out at bottom of pit, said that on Monday, a fortnight past, he was standing with his left hand on the empty tub that he had pulled out. He saw a flash of light come down and heard a noise like a gun; he would be two and a half yards from the pit. It struck on the plate, or flat-sheet, to the north of the side he was standing on. He felt something strike him on the arm, and saw the light divide when it struck. His arm was numbed for a time after, which made him think that part went past him. He had the numbness all the afternoon ; he felt something go all over him. When he went home and got washed, his arm was yellow from the wrist to the elbow. His sister, Ann Watson, who is about 21 years of age, saw the arm was yellow, but no one else, He had no pain in it afterwards. He heard a heavy peal of thunder immediately after the light fell. The light, when it struck, seemed very bright, but he did not notice it brighten up the place to any distance.

The evidence of the five following witnesses relates to the portion of electric fluid which was observed to go up the North Incline.

Thomas Crisp said, he was a deputy, and on the afternoon of July 12th, the Monday previous to the Risca explosion (which occurred on Thursday, July 15th), he was on the north side of the pit, about 20 or 30 yards from the top of the Incline bank, in company with John Greener. (C, Plate IX.) They were bringing down a tram used for carrying timber when the electric fluid passed. Greener had his hand on the tram but he had not. He (Crisp) saw something like a lot of fire flying, and he thought the tram had cut the joint. It was like as though a person had trodden upon matches and they had gone off. Greener saw it as well as he. They then thought there had been a fall upon the rails, but as they proceeded down the bank no fall was to be seen. The fire came right up to the inclined plane; it seemed a little larger than the light of a candle, and came close by the tram where he was standing. To the best of his judgment it came along the metals.

John Greener said, that when going down the Incline with Crisp, and having hold of the tram, he saw a light on the rail about twenty yards off, about the size of a candle, flickering, not steady. It appeared to travel along the rail, and as it passed the train it made a noise like the crack of a pistol, which he thought proceeded from matches or something on the way that was cracking. He saw it first fifty or sixty yards before it came to where he was standing. They were not far from a guiding-wheel which changed the direction of the rope, and there were men working at the wheel both east and west in a new place recently commenced. He had no idea that it was lightning as it flashed past; they had never seen such an appearance before.

In answer to some remarks from the visitors it was elicited that the rails were fished that it was not noticed if the lightning came down the rails or the rope; that it was a self-acting incline; it was a flickering unsteady light that Greener saw which was past in a second; there was a noise as it came to the tram as of a pistol or gun shot; it was not very loud, and a similar noise was heard as it left the tram; the metallic contact might have been broken by a fish plate being off. Crisp said that he did not think of its being lightning, but supposed that matches had been dropped which crackled as they went off.

Nicholson Watson said, he was going up the Incline bank and met Crisp and Greener, his feet were on the rail, and he saw a light go close past them, which seemed to numb them for a short time; as it passed it was like the spark and noise from the cap of a pistol when exploded. There was a wheel near and two men hewing close to it; he went to the men, who said they had heard a great noise, which they thought had been caused by the electric light being tried at bank. Two hewers at the bank-head, William Athey and John Brown, told him they had heard a report going off like a gun, and he remarked to them, "They are trying the electric lights from bank," but he did not think of its being lightning till he got to the shaft.

John Hagan, a putter, said, he saw lightning come along the plates. (D, Plate IX.) It caught him as it passed, giving him a sort of queer feeling in the leg's; it made a sharp cracking noise in the plates, like a gun ; it passed him as he was going down with his pony. He had seen matches put on the rails to be exploded by the trams passing over them — and the appearance was like that caused by the trams going over the matches. He thought it was lightning at first, before any one had time to tell him, because of the feeling about his legs. Where he was standing the rails were about 4 feet long, not fished, and with a good space between them.

Thomas Spring said, he was a hewer on the north side, and was working about fifty yards from the bank-head. (D, Plate IX.) He heard the noise and went a few steps back from where he was working. He asked the lad, John Hagan, what it was, and he replied it was lightning. He thought it was a fall of stone at the bank-head, and to be sure that there was no one hurt he went out to see.

The statements of the four following witnesses relate to the portion on the south side of the shaft.

George Crisp said, he was a siding minder, and was about fifty yards from the shaft. (A, Plate IX.) He heard a cracking noise, and saw a bright light and flash of fire against the big binding sheave (two feet diameter) like five or six matches going off at once. All the tubs near at hand were at rest at the time. He had seen matches placed on the rail and exploded by the trams passing over them, but the light and noise could not be explained in this way now, because there were no tubs running by at the time.

Matthew Hardy, said, he was an engine flatter, and worked close to the shaft; was about 100 yards along the shaft siding when he saw a light like a spark from a lamp, and there was a noise like a match being struck by a tub passing over it. It was a custom in the pit to place matches on the rails at intervals of a yard or two apart, like fog signals on a way. The light appeared to be close to him on the rope, which was running, but he did not notice the direction in which the light passed.

George Nicholson, rolleywayman, said, he was at the outbye side of the junction, 700 yards south of the shaft. (B, Plate IX.) He saw no light, but heard a report as if a man had struck a plate a sharp blow with a hammer, although it could not have been that, as there was nobody about but himself and Miller.

John Pyle said he was the set-rider on the south side. (B, Plate IX.) He was about 700 yards from the shaft, near the junction, changing the ropes, and was just going to the siding when he heard a noise like somebody striking a match, or louder than that, but he saw nothing.

The gentlemen who have conducted this inquiry do not deem it necessary to make any comment upon the evidence, but simply to remark that they have every reason to believe that the facts recorded by the several witnesses are in every way to be relied upon, and that the information thus obtained forms a valuable record of the occurrence, and places beyond doubt the possibility of lightning penetrating into the workings of collieries. All further observations, which can only be based on conjecture, it is considered had better be made during the discussion after the communication has been read, which it is hoped will be taken up by some of the members of the Institute who have made electricity their special study.