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Page:Popular Science Monthly Volume 25.djvu/839

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PROTECTION AGAINST LIGHTNING.
821

ductor by a solid stone wall four feet six inches thick, there was fixed a gas-standard of iron, which was used in lighting the church. The lightning in its descent left the conductor at this point, and passed through the solid mass of masonry, to reach the standard, knocking out a large circular breach in the stone-work by the way. It preferred to take this devious path, and to avail itself of the facilities which the capacious gas-main connections of the town afforded it for the accomplishment of its escape into the earth, rather than to embarrass itself with the still more onerous task of forcing its way into the dry soil at the bottom of the tower, through the too briefly terminated coil of the rope. The floor and pews of the church were found to be on fire the day after the storm, and some considerable mischief was done before the conflagration could be stopped. This fire was almost certainly due to the circumstance that the gas-pipe from the standard was connected with the meter and the mains by means of a short length of soft fusible gas-pipe in a small basement-room under the floor of the church; But, when an investigation into the cause of the fire was subsequently instituted, no one seemed to be able to say whether an escape of gas from the injured pipe had been lit up at the time of the lightning-discharge, or whether the actual lighting of the gas was due to some subsequent introduction of a burning flame into the neighborhood of the gas-meter.

The obvious method of guarding against accidents of this class is the simple expedient, wherever gas-pipes are concerned, of connecting the termination of the conductor directly, by means of a sufficiently ample metallic band, with one of the large iron pipes of the general system of the mains. If this had been done with the lower extremity of the rope, in the case of the tower of All Saints Church, instead of merely twisting it around a stone in the dry surface-soil, the injury to the wall at the bottom of the tower, and the consequent train of accidents which culminated in the burning of the floor of the church, would have been physically impossible. The lightning would then have gone through the large, open, and direct route to the mains instead of piercing a stone wall four feet six inches thick, and leaping across a small fusible gas-pipe to get there.

The case is precisely of the same nature as the accidents alluded to by Professor Rousseau. The earth communication of the copper rope being inferior to that of the neighboring gas-pipe, the lightning quitted the rope to get at the ground through the pipe. No more striking and instructive illustration of the danger of insufficient earth contacts could possibly be furnished.

A still more curious illustration of a somewhat similar kind occurred at Chichester, simultaneously with the destruction of the lightning-rod which has been already alluded to. The boundary of the cathedral close in one direction is marked by a tall and stout iron rail, which divides its precincts from the main street of the town. On