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such building, and within a foot or two of the top, it may be proper to fix a rounded bar of metal, and to continue it down along the side of the wall to any kind of moisture in the ground. But if the building bappens to be mounted with an iron spindle, for supporting a vane, or other ornament, and it should not be conve. nient to have it taken away, then the bar of metal ought to com. municate with that spindle. And as to the diameter of such a metal bar, it will probably depend on the height of the building; for it is apprehended the great church of St. Paul's, to complete the partial conductors (which are the metallic cross, ball, gallery, dome, &c.) and secure it effectually, would require a bar of metal two inches diameter, if not more; and a building like the British Museum, one considerably less. But it appears there is no occa. sion for any at that repository, as it is already provided, though from accident, like many other buildings, with very effectual con. ductors. The copings of the roof, and the several spouts, which are continued from it into the ground, being all of lead.
That conductors ought to be thicker than is generally imagined, seems to appear from a late instance taken notice of in St. Bride's church, by Mr. Delaval, and Dr. Watson, where an iron bar, 21 inches broad, and half an inch thick, or more, was bent and broken asunder by the violence of the lightning. The Eddystone Lighthouse, which stands on a rock, surrounded by the sea, the work of Mr. Smeaton, was thought to be an object very likely to suffer by lightning; and the more so, as the top of it consisted of a copper ball, two feet in diameter, with a chimney of the same metal, passing through it down to the second floor, but no farther. Directions were therefore given to make a communication of metal from the lowest part of the copper chimney down to the sea; which was executed accordingly about the year 1760, or soon after the building was finished. Now if, instead of the copper ball, a pointed bar of metal had been put in its place, or above it, and communicated with the conducting matter below, there is no saying what might be the consequence of so powerful an invitation, to an edifice thus particularly situated.
Since the former part of this paper was communicated to the R. S., that is, on the 5th of August, 1764, I received the follow. ing account from Captain Dibden, commander of a merchant ship, who says, that in the year 1759, he was taken by the French, and carried prisoner to Fort Royal, in Martinico. That in removing him thence some time after, and on foot, to St. Pierre, which is about twenty miles, his conductors, or guard, stopped at a small chapel, five miles from the last place, to shelter themselves from the heavy rain which fell during a violent thunder-storn. That the chapel had no steeple or tower belonging to it, but stood on an eminence, with three or four poor low houses near it. That soun after they were thus sheltered, a violent flash of lightning struck two soldiers dead, who had been leaning against the wall of the chapel, between two buttresses, and not far from the rest of the company, being all on the leeward side of the chapel. That it made an opening in the wall about four feet high, and about three feet broad, and in that part only against which they rested.
That Captain Dibden, along with other persons, entered at this hole immediately after, to see if any other damage had been done to the chapel. That they observed a square bar of iron near the hole, and on the ground, about four feet long, and 14 inches thick, making an angle with the wall, as they suppose, to support the upper part of an inclined tombstone, which was also thrown down and broken to pieces. That this bar was joined in the middle to one end of another bar, about one foot long, and one inch thick, which laid horizontally, and, passing to the wall, had been there fastened with lead. That the lightning, in rushing along the inclined bar, had wasted or reduced its thickness in some places very considerably, insomuch that it looked like a burnt poker which had been long used; and broke the bar into two pieces, about an inch above the joining of the lesser bar, the ends of which had a burot flaky appearance. That the other parts of the bar were changed in colour to a grey, or whitish hue, resembling iron after it has been exposed to a violent heat and then suffered to cool. That the horizontal bar had also undergone an extraordinary change by the lightning, but particularly at that end next the wall of the chapel, it being reduced from one inch in diameter to the size of a slender wire, but tapering towards the wall. That when the soldiers rested against the wall, their heads were about the same height with the shortest bar; and, from what he can recul. lect, were very near being opposite to that end which was inserted in the wall. That the two soldiers were forced from the wall at the same instant by the lightning ; so that their feet, which were one yard or more from it, were nearest to the wall, and their heads the farthest off. That their flesh appeared very black. That their clothes were burnt and scorched in many parts, and their belts shrivelled up, as if they had been exposed to a large fire. That Captain Dibden, and other people, felt a disagreeable kind of an electric shock, at the same instant that the soldiers were killed.
Captain Dibden gave an account also, that he was lately at Vir. ginia, 1763 : that the inhabitants of Norfolk had changed their opinions in respect to fixing of wires and small rods of iron on the tops of their houses; from the frequent instances they have lately had of their being melted, or destroyed, by the violence of the lightning: and that now they adopted, in their stead, rods of iron from half an inch thick to three.fourths of an inch thick, or more. That those rods ended in a point at the top, and extended from three feet above their houses down to the ground; and that many houses had one of these conducting irons at each end. The Capt. added, that though the pine trees are considerably higher than the oaks in the American woods, yet the oaks are the oftenest attacked by the lightning: and that he does not remember any oaks grow. ing among the pine trees, when the latter have suffered by light. ping, which must be owing to the greater resistance arising from the unctuous nature of the pine trees.
[Phil. Trans. 1764.
Thunder-storms remarkable from their violence, or the pecu.
liarity of their effects,
1. Strange effect of Thunder and Lightning on Wheat and
Rye in the Granaries of Dantzic.
By M. Christopher Kirby.
You doubtless know how much this city is famed for its nume. rous and convenient granaries, it being the repository of all sorts of grain the fruitful kingdom of Poland affords. In those grana. ries are laid up chiefly wheat and rye, in parcels of twenty to
thirty and sixty lasts in one chamber, according to its size, and the dryness of the corn; which they turn over three, four, five, six times a week, as need requires, to keep it sweet and fit for shipping. Now it happened, that about the latter end of March and April last, we had much and violent thunder and lightning, which had this unhappy effect on all the parcels of wbeat and rye of the last year's growth, that, though over night they were dry, sweet, and fit for shipping, the next morning they had lost all these good qualities, and were become clammy and stinking, and consequently unfit to be shipped away for the present; so that the owners were forced to cause it to be turned over two or three times a day, and yet it required six weeks, if not longer, before it was recovered.
This is a thing which often happens to corn that has not lain in the
granary a whole year, or not sweat thoroughly in the straw before it be thrashed out. An accident little noted, yet in my judgment worth the enquiring into; for, though the alterations caused by thunder in liquors, be taken notice of, and probable reasons given for them, yet I judge this somewhat more abstruse, and therefore more worth while to be considered.
[Phil. Trans. 1673.
2. Extraordinary Thunder Storm near Aberdeen.
In a letter to Dr. George Garden,
This happened July 24, 1695. The day was clear and plea. sant, till about half past three, afternoon, when some rain fell; then two claps of thunder, rather moderate; then fell a heavy shower of hail, accompanied with a third clap of thunder, very tremendous, attended with great damage to the houses and people, In a school were the master and fifteen boys; the building was perforated and shattered in several places, illumined as with a strong and sudden fire, attended with a suffocating and sulphu. reous smell and dark smoke. The persons were all either struck down, or badly wounded and bruised. Four were killed out. right, the rest recovered in due time. In the parts where they were struck, which was chiefly about the shoulders, the flesh was much discoloured, and the clothes there cut or perforated, to appearance as if eaten by rats.
3. Thunder-storm near Halifax, December 22, 1698 : fatal to a
By Ralph Thoresby, Esq. F.R.S. Jeremiah Skelton, of Warley, near Halifax, Yorkshire, observing a storm coming, hastened to gather in some of the corn which was out at a farm of his father's in the Cold Edge, about a quarter of a mile from their own dwelling; while at this work, bringing in bur. den and casting it upon the barn-floor, the tempest began as he came forth again; whereupon he stepped aside for shelter within the barn door, and while there, was struck with a dreadful filash of fire. The young man was a sad spectacle, being beaten down, quite dead, and many stones about him ; he was laid upon his face, w holly naked, save a small part of bis shirt about his neck, and a piece of a stocking on one foot, and so much of a coat-sleeve as covered the wrist of one arm; his shoes driven from his feet, one not to be found, and the other split; his hat not to be found after search, and the rest of his garments torn into small shreds, and cast at considerable distances, one piece from another; the hair of his head and beard singed, as if with a candle, and a little hole below his left eye, which was probably made with the fall upon a stone, for there was a great breach made on the barn, the door tops, both of stone, broken, and the wall above them fallen, with the slate and water.tables.
4. Singular effects of a Storm on a House and its Furniture,
at New Forge, Ireland.
Mrs. Close gave Mr. Molyneaux the following account of the effects of thunder and lightning, on her house at New Forge, in the county of Down, in Ireland, on Aug. 9, 1707 : she observed, that the whole day was close, hot, and sultry, with little or no wind stir. ring, till towards the evening; that there was a small breeze with some mizzling rain, wbich lasted about an hour; that as the air darkened after sun-set, she saw several faint flashes of lightning, and heard some thunder claps, as at a distance ; that between ten