XXV. An Account of the Effects of Lightning upon the Steeple and Church of Lestwithiel, Cornwall; in a Letter to the Right Honourable the Earl of Macclesfield, President of the R.S. By Mr. John Smeaton, F.R.S.
Read April 21, 1757.
JAnuary 25. 1757. about five o'clock in the evening, returning home from the Edystone works near Plymouth, I observed four flashes of lightning, within the space of six or seven minutes, towards the west; but heard no noise of thunder[123]. A few days after, I was informed, that the same evening the lightning had shattered the church of Lestwithiel in a very surprising manner.
The 1st of March I was at Lestwithiel: they had then begun to repair the damages; but had not made such a such progress, but that the principal effects were equally observable as at first. I observed, and was informed, as follows:
At the time before-mentioned, the inhabitants were alarmed by a violent flash of lightning, accompanied with thunder so sudden, loud, and dreadful, that every one thought the house he was in was falling upon him; almost every one being within doors, on account of a violent shower of rain, which preceded the lightning: so that no body saw or heard any thing of the mischief done to the church, till it was observed accidentally after the shower.
The steeple is carried up, plain and square, to about 49 feet, with a kind of slate-stone, rough-casted on the outside; upon which is formed a very elegant octogon Gothic lanthorn about 9 feet high, and thereon a stone spire about 52 feet height, with a spindle and vane rising about 3 feet above the stone: so that the whole together was about 113 feet. Each face of the lanthorn finishes above with a sort of a Gothic pediment, with a little pinacle upon each, separated from the body of the spire.
I will not affirm, that the lightning entered in at the spindle or vane at top; but will suppose it, for the sake of methodizing the facts. The vane was of plate copper, which being turned round, and rivetted, made a socket to turn upon. The spindle did not reach thro' the socket, but the weight of the vane rested upon the top of the spindle, the top of the socket being closed. About the vane were many acute angles, and some almost sharp; but I did not observe any pointing directly upward. The vane was much bruised, which might be occasioned by the fall; but the socket was rent open, as if it had been burnt by gunpowder; and in such a manner, as I cannot conceive could be occasioned by the fall. Under the spindle, that carried the vane, was a bar of much the same size and length[124], that passed thro' the center of several of the uppermost stones successively, in order to unite them the more firmly together, and was run in with lead: all which surrounding stones were broke off, except one, which, together with the bar, fell down within the tower.
The shell of the spire, as far down as 35 feet from the top, was no more than 7 inches thick, and the courses about the same height: so that scarce any one stone in the spire could weigh more than 30 or 40 pounds; but they were joined together at the ends, with mortoise and tenon, in a curious manner. Above 20 feet of the upper part was intirely thrown down, and dispersed in all directions; and, as I was informed, some pieces were found at the distance of 200 yards. A great many stones fell upon the roof of the church; and several made their way thro' both roof and cieling down into the church, breaking the pews, and whatever they fell upon. Six feet still lower the spire was separated; the westermost half being thrown down; the eastern half was left standing, but disjointed, and in so critical a posture, that it seemed ready to fall every moment: so that this was ordered to be taken down immediately; and likewise to 6 feet below, the work being found remarkably shattered. In this condition it was when I saw it. The whole of the spire I found much cracked and damaged, but the remainder of the 7 inch shell so greatly, that there seemed scarcely a whole joint.
The pediments over every face of the lanthorn were damaged more or less; but the whole ashlering of that to the N.W. was torn off from the inner wall, to which it was connected. At first sight this might seem to be done by the falling of the stones from above; but I was convinced to the contrary, by observing, that several of the pediments were damaged, and even stones struck out, where the little pinacles above them were left standing.
About the top of the lanthorn is a bell for the clock to strike on: it is hung upon a cross-bar, with gudgeons at each end; the whole being suspended to a beam laid across the tower. The cross-bar was so bent, that the clock-hammer would not touch the bell by above 2 inches. This could not be done by the falling of stones, because the beam would defend the bell from receiving any stroke in the direction to which the cross-bar was bent. As to the wire, that drew the hammer, as I was informed, not one bit of it could be found.