SINGULAR EFFECT OF LIGHTNING.

Colonist, Volume III, Issue 237, 27 January 1860, Page 3

SINGULAR EFFECT OF LIGHTNING.

At the November meeting of the philosophical society of New South Wales, held in the hall of the Australian Library, a very curious circumstance [was brought und the notice of the members present by Professor Smith, respecting the singular effect of lightning upon gaspipe. Alluding to the phenomenon, the Professor says:— " In his laboratory at the University recently he had had a connection made with iron pipes brought up from the city; the gas pipe was laid along the front of the building below the surface of the ground. The pipe was a cast iron one three inche;s in diameter, and the connection with he lawas by a small iron pipe joining a tin pipe under the floor. There was also a system of lead water pipe following neatly the course of the tin gas pipe, and terminating underneath the doorway where the gas pipe entered the laboratory ; at this point, or just inside the, doorway the tin gas pipe touched the lead water pipe. On Monday afternoon he left his gas hoider half full of gas,—there was nearly twenty cubic feet in it. The stopcock between the outside pipe and the laboratory was closed, and the junction with the gas holder left open. On Tuesday morning he tried to light the gas, but found there was none. On going round to ascertain the cause, he found that his gas holder was empty, though all the stopcocks were shut, and then on opening the outside stopcock he found that there was no pressure on the pressure guage, but he soon observed that the room was getting full of gas, from which he inferred that there must be somewhere in the pipe a hole as large as its diameter; otherwise there would have been some pressure on the guage. It then occurred to him that this sccident might be connected with the fact that on Monday afternoon, 14th November, the University had been struck by lightning, in one of the shears on the tower a deep groove an inch wide had been cut Out, and there was a terrific crash, suggesting to those in the building the idea that the roof had fallen in. There was a lightning con ductor attached to the chimney of the laboratory, and this entered the ground eighteen feet from the gas pipe, termina ting six feet below the surface, in a large copper plate. On sending for the plumber who laid the pipes, he suggested thai; a rat had gnawn through the pipe, finding it obstructing his way; but on taking up the floor they discovered that the accident must have been due to lightning. On the one side of the pipe, where it had touched the lead water-pipe, was an irregular oval aperture about an inch long and half an inch wide, and right opposite, on the other side of the pipe was a smaller rounded aperture measuring half an inch by three eights, the tin being thinned away as if had been beaten out. A lump of melted tin, weighing forty-five grains, lay below the orifice. What had happened wss tolerably clear; one of the pipes had been conveying a very powerful charge of electricity, and coming to the point where it touched the other the. electricity preferred changing its route, and in leaping from the one to the other it made two great holes. He observed that there was an indent in the lead water-pipe, and a piece of lead melted. It was a puzzling thing to account for the hole at the back of the pipe. The corner of a brick touched it at that part, and the aperture there had quite a different appearance from that on the other side, the edge on one side (next the brick) being thin and sharp, while on the other it was thickened and melted. The blackening inside the pipe would 'be accounted for by the gas being decomposed by the electricity. There were many curious points connected with this case. In the first place, where did the lightning come from? He could scarcely imagine'that 1 the discharge could have come from the tower and run along the pipe which was buried in the ground for nearly two hundred feet. It seemed more probable that the discharge was delivered by the laboratory conductor, and had then passed through the grouud to the gas pipe, though that was eighteen feet away. He thought it might have come along the gas pipe first and then taken to the water-pipe, as a better conductor. There was still another supposition, however, and, perhaps, the most probable one. The lightning might have struck the south-east corner* of the* laboratory, and, being conducted by the lead gutter, to the lead cistern under the roof, and thence down the water-pipe to the laboratory, whence it made its exit by the gas-pipe^ If this supposition be correct, it shoffs how limited was the protective power of the lightning conductor attached to a neighboring chimney. The man at the turnpike saw the lightning strike theUniversity; he described it not as a flask of light, but as a ball of fire which came down in front of the building. It was ire* markable that the gas was not ignited by.. the electricity, and the laboratory set ork. fire."