sorbed and conducted by the masses of stone. The damage done to the steeple is, except near the top, confined almost to the east and north-east side, and most generally where the ends of the iron bars have been inserted into the stone or placed under it; and in some places, by its violence in the stone, its passage may be traced from one iron bar to another. And it is very remarkable, that to lessen the quantity of stone in this beautiful steeple, in several parts cramps of iron have been employed; and on these, stones of no great thickness have been placed, both by way of ornament and to cover the cramped joint. In several places these square stones have, on account of their covering the iron, been quite blown off, and thrown away. A great number of stones, some of them large ones, were thrown from the steeple, three of which fell on the roof of the church, and did great damage to it; and one of these broke through the large timbers which form it, and lodged in the gallery.

In the tower of the steeple, in the room where the bells are placed, the lightning took the south-west window above the bells and close to the window, not far from an iron bar, which goes round, and rent out several large stones; some of which fell into the bell, which was very near this part of the steeple, and was the largest in the steeple; and passing below the bell, tore out at another place in a line with the former, a great number more. One of the stones, torn out above the bell, was thrown to the north-east side of the tower. Between the two places in which the lightning had here exerted its fury, the wooden block which confined the axis of the frame of the great bell, and was fastened down with two iron staples, was thrown off, and the staples torn out. No damage at present seems done to the bell.

It is remarkable, that less than twenty years ago, one of the stones of the obelisk of this steeple was observed to be moved from its place, and project some inches over those under it. This stone was about seven feet from the top of the obelisk. Danger being apprehended from this state of the spire, it was taken down to the place where the stone was removed, and rebuilt with new stone. This accident at that time was supposed to be owing to the ringing of the bells; but it is highly probable, from what has lately happened, that as that stone was removed from its place, very near to that part of the spire where it is now cracked and shivered quite across, and several pieces of stone thrown down, it was owing to the same cause as the present damage, viz., lightning, though not at that time adverted to.

The lightning on June 18, came from the west and south-west; the damage done both to St. Bride's church and South-Weald, was on the east and north-east sides, except that on the bell loft at St. Bride's. The stones, both from the steeple of St. Bride's and in its tower were thrown to the east and north-east.

Since the communication of this paper to the Royal Society, the steeple of St. Bride's has been surveyed, and found so very much

damaged in several of its parts, that eighty-five feet have been taken down in order to restore it substantially. Within these eighty-five feet are comprehended the obelisk, placed at the top of the steeple, the small dome immediately under it, the space between that and the uppermost or composite story, the composite story, and the Ionic story. This last, on the east and north sides, was taken down to its bottom: but on the other sides, as they were not injured, some parts were permitted to stand. Three piers were likewise taken down of the second Tuscan story, and one pier of the first. The scaffolding to take this down and rebuild it enabled me minutely to examine, not only the damages occasioned by the lightning, but the manner of its progress. This examination confirmed the opinion of the cause and manner of this accident, which I communicated to the Royal Society soon after it happened, and before a near inspection could be obtained. It completely indicated the great danger of insulated masses of metal to buildings from lightning; and on the contrary evinced the utility and importance of masses of metal continued, and properly conducted, in defending them from its direful effects. The iron and lead employed in this steeple, in order to strengthen and preserve it, did almost occasion its destruction: though after it was struck by the lightning, had it not been for these materials keeping the remaining parts together, a great part of the steeple must have fallen.

The operation and progress of the lightning, in the obelisk and upper parts of the steeple, deserve more particular attention. To form a more perfect idea of these, the following measures will in some degree contribute.

The height of the octagonal obelisk...
Length of the iron spindle

Thickness of the spindle, where inserted into the

stone...

Its length inserted into the stone...

From the bottom of the spindle to the first cramped joints.....

Three courses of stones without cramps

From the bottom of the spindle to the first concealed chain ....

From the first concealed chain one foot above the base of the obelisk to the first cross chain.... From the first cross chain to the second, placed in the dome

Feet. Inches.

The vane, the cross above it, the ball and its socket, which covered so much of the spindle as arose above the stone, to near ten feet of its length, were of copper gilt. This length of the spindle was cylindrical, but the other part was made square, where it began to be inserted into the stone. To fasten this spindle more securely in

B

the courses of stone, melted lead had been poured. This lead, in the two lower courses of stone through which the spindle had passed, not only filled all the space left between the spindle and the stones, but had, as it were, ramified itself not only between the joints of the stones, but had insinuated itself in its melted state into all their small clefts and interstices. The spindle terminated in one stone, which occupied the whole area of the obelisk, and was three feet and near two inches in diameter, and one foot in thickness. Into this stone the spindle was inserted five inches of its depth, and fastened by melted lead. Under this stone the obelisk was hollow, but above it was solid, excepting the space left for the spindle.

On examining these several particulars, no injury had been done by the lightning to the vane, its cross, copper ball, or spindle. Of the seven courses of stone at the upper part of the obelisk, and which were above the whole stone into which the spindle was inserted, the five upper courses, though connected together at top and bottom with iron collars soldered with lead, were not damaged; but the two stones which formed the sixth course were cracked, shivered, and fragments thrown from them. The seventh course consisted likewise of two solid stones. These were burst from the spindle, which was, by the intervention of the lead, connected with them, broken into many parts; each was moved from its place; some pieces were thrown down, and one large one projected five inches over the stone immediately under it. The whole stone, into which the spindle was inserted, and on which it rested, was burst from the centre into a great many pieces, and every piece removed from its place. Some of these were thrown from the steeple. Several of the large masses of this stone, which still cohered, were very much shivered. The centre of the stone, on and near which the spindle rested, was beaten to powder, and a hole made through the under part of the stone. That this stone in this condition should still support the seven courses above it, which weighed four tons, exclusive of the spindle, vane, and their appurtenances; and that the whole did not fall when struck with the lightning, is in no small degree surprising. From the bottom of the spindle to the first course of stone, where the workmen had used iron cramps, the distance was five feet seven inches. These cramps were bedded in the stone. Part of the lightning, from the bottom of the spindle through the hole just now mentioned, seized these cramps, and threw off large scales of stones at their ends. From these there were three courses of stone, in which there were no cramps, these suffered nothing. In edifices of this kind, for additional strength, the builders employ bars of iron, connected together in such a manner as their exigencies require; and these, though they have no links, are denominated chains. These are sometimes so adapted to the courses of stone as not to be visible, and are perfectly concealed at other times, they are in part visible, and in part concealed. The first metal that occurred after the cramps before mentioned, was a concealed chain, one foot above the base of

the obelisk, and two feet above the first cross chain. Here two stones were burst and shattered. In the course of stone where the first cross chain was inserted, and the several stones connected by iron cramps, many of the stones were much shattered. At the base of the dome, near nine feet below the first cross chain, was a second. This chain was a double cross connected at its ends with a circle of iron, which was bedded into the whole course, and fastened by melted lead. Here the lightning made great ravage, burst and threw of the stones in which the iron circle was bedded, and tore out part of the roof of the dome, threw off two pieces of the cornice and one of the vases which was contiguous to it. These two pieces of cornice weighed 1,200 pounds. The courses of stone between the two chains, except those just now mentioned, were not injured.

To what is here said, I shall only add, that in no part the steeple was injured, except where the stones were in contact, or very near the iron and lead empoyed in its building; and the quantity of stone burst, spoiled, or so much damaged as not fit to be used again, amounts, as I am informed by Mr. Stanes, a very honest and ingenious mason, who has contracted to repair the damages done by the lightning, to not less than twenty-five tons. An amazing quantity!

The above mentioned Mr. Stanes was employed a few years since in the repair of the steeple of St. Mary le Bow, in Cheapside, which was injured by a rare and uncommon accident. At its erection, the builders had employed, near the top of the spire, for additional security, several iron cramps; the ends of which, by being exposed to the weather, became rusty, swelled, and so much enlarged, as to raise the stones above them, and to deflect the top of the spire six inches from the perpendicular. Danger being apprehended from this situation, the spire was taken down several feet of its length, and properly repaired. This ought to be a caution to succeeding builders, that if, in edifices of this kind, they find it expedient to employ cramps, they should be either of copper, which is not liable to swell by moisture, or if iron be used, so much space should be left in the under bed of the stones, which immediately cover the cramps, that they may have room to extend themselves without danger to the building. This remark, though not immediately relating to our present purpose, will not, I hope, be thought impertinent in this place.

But to return this thunder storm had been preceded by several very warm days. The nights had scarcely furnished any dew the air was quite dry, and in a state perfectly unfit to part with its highly accumulated electricity without violent efforts. This great dryness made the stones of St. Bride's steeple, and all other buildings under the like circumstances, far less fit than if they had been in a moist state, to conduct the lightning and prevent the mischief. For though this thunder storm ended in a heavy shower of rain, none except a very few large drops fell till after the church was struck; and I have no doubt, but that the succeeding rain prevented

many accidents of a similar kind, by bringing down with every drop of it part of the electric matter; and thereby restoring the equilibrium between the earth and clouds. It is frequently taken notice of in attending to the apparatus for observing the electricity of the clouds, that though the sky is much darkened, and there have been several claps of thunder at no great distance, yet the apparatus will be scarcely affected by it; but as soon as the rain begins, and falls on so much of the apparatus as is placed in the open air, the bells of the apparatus in the house ring, and the electrical snaps succeed each other in a very extraordinary manner. This demonstrates, that every drop of rain brings down part of the electric matter of a thunder cloud, and dissipates it in the earth and water, and prevents the mischiefs of its violent and sudden explosion. Hence, when the heavens have a menacing appearance, a shower of rain is much to be wished for.

From these considerations, I have no doubt, but that the mischief done to St. Bride's steeple was owing to the efforts of the lightning, after it had possessed the apparatus of the weathercock, endeavouring to force itself a passage from thence to the iron work employed in the steeple. As this must be done per saltum, there being no regular metallic communication, it is no wonder, when its force is vehement, that it rends every thing which is not metallic that obstructs its easy passage; and in this particular instance, the ravages increased as the lightning to a certain distance came down the steeple. To procure this easy passage, and avert the ravage occasioned by the want of it in future, as much as our present knowledge in these matters will enable us to do, I cannot sufficiently recommend metallic communications between the metal at the top and water, either as has been before mentioned, or in any other convenient manner, taking care not to be too frugal of the metal employed. This was first suggested by Dr. Franklin, and since much used in Philadelphia, and other parts of North America.

Near the same time that the mischief was done to St. Bride's church, the mast of his Majesty's ship Ramillies, lying at Chatham, was split and torn to pieces by the lightning. This is the less extraordinary, as, from its height, figure and constituent parts, the mast of a ship stops the progress of lightning much more than edifices of the same height, made of brick or stone. This therefore seems to require particular attention; but on this head I fully explained myself in my letter to the late Lord Anson,* and shall therefore decline saying any thing further of it in this place.

I flatter myself, that what has here lately happened will tend to occassion the applying of an apparatus of this sort to all buildings, at least of value and extent. No steeple should certainly be without it; and in most, if the iron work of the weathercock can be easily got at, it may be adapted with very little trouble or expense.