APPENDIX I.GENERAL CORRESPONDENCE.

Trinity House, London, E.C.,6th February, 1880.

Trinity House, London, E.C.,

6th February, 1880.

Sir,

I am directed by the board to transmit to you herewith, for the information of the Lightning Rod Conference, copies of reports made by Professor Faraday to this Corporation, one respecting a remarkable stroke of lightning which occurred at the Eddystone Lighthouse in January, 1853, and the other upon a similar accident experienced at the Nash Lights in August, 1852.

The case to which Admiral Sullivan directed the attention of the Conference, as stated in your letter of the 30th October last, was probably one of these two.

Should you desire any further details in connection with this subject, the Corporation desire me to assure you of the pleasure with which they will afford any information at their command.

I am, Sir,Your obedient servant,ROBIN ALLEN.

I am, Sir,

Your obedient servant,

ROBIN ALLEN.

G. J. Symons, Esq.

[We have been favoured with copies of three separate reports by Professor Faraday, and think that it is better to give them in chronological order. There is only one other point in the correspondence from the Trinity House which it seems necessary to mention, viz., that the sections of the copper rods now used are as under.—Ed.]

MAIN CONDUCTOR.1½ in.

CONNECTING BRANCHES.1¼ in.

REPORT on the LIGHTNING RODS of LIGHTHOUSES, 1843.

Dungeness.—Dungeness Lighthouse stands about 14 feet above the sea and measures 97 feet to the top of the lantern. The tower is of brick with wood floors; the roof and frame of the lantern are of metal seated upon a stone pedestal, to which it is secured. There is no conductor to the building. The weathercock is fitted with aglass repeller, and a rod similarly fitted is attached to the two copper flues which rise by the side of the lantern.

Eddystone.—The height of the top of the lantern of the Eddystone above the sea is about 95 feet. The roof and framing of the lantern are of metal, secured through a stone plinth to the gallery of the tower by metal fastenings. A conductor of copper rod, ¾ inch diameter, is attached to the outside of the building; the rod rises 3 feet above the top of the lantern and terminates in the sea at low water; it is fixed to the tower and lantern by metal stays and fastenings and is isolated by glass ferules. To give stability to the building eight wrought iron ties are fixed in the interior of the house, extending downwards from the underside of the lantern floor through the next two stories, terminating by inserting the ends into the stone floor, the upper ends are riveted into an iron ring round the manhole in the ceiling and further secured by iron bolts passing through the stonework and communicating indirectly with the metal work of the lantern.

Eddystone.

Spurn Point High Light.

Spurn Point High Light.—The Spurn High Light stands about 16 feet above the level of the sea, and measures 100 feet to the top of the lantern. The tower is of brick with wood floors; the roof andframing of the lantern are of metal, seated upon a stone plinth to which it is secured; the weathercock is surmounted by a glass repeller. An isolated conductor of copper rod, ¾ inch diameter, is attached to the outside of the tower rising some feet above the lantern and passing down the side of the tower below the surface of the ground.

South Foreland.—The South Foreland High Light stands above 300 feet above the sea, and measures from the ground to the top of the lantern 67 feet. The tower is of brick, the lantern roof and framing are of metal with a cast iron pedestal; the weathercock is fitted with a glass repeller. A conductor of copper rod, ¾ inch diameter, is attached to the outside of the tower, of the same height as the weathercock. The rod is fastened to the lantern and tower with metal stays and fastenings, and passes into the ground, turning off at right angles to the tower a little below the surface. A copper flue connected with a stove in the base of the tower, passes up the centre of the tower through the roof of the lantern, to the lower end of which a copper rod has been attached, which is carried to the outside of the building into the ground.

South Foreland High Light.

The undersigned have, according to their instructions, met and considered the circumstances under which lighthouses are placed as respects lightning, and have arrived at the following conclusions:—

That lighthouses should be well defended from the top to the bottom.

That as respects the top, the metal of the lantern, and upwards, is sufficient to meet every need, and satisfy every desire and fear.

That for the rest of the course down the tower, a copper rod ¾ of an inch in diameter is quite, and more than, sufficient.

That at the bottom, where the rod enters the earth, it is desirable at its termination to connect it metallically with a sheet of copper 3 or 4 feet long by 2 feet or more wide; the latter to be buried in the earth, so as to give extensive contact with it.

That glass repellers are in every case useless.

That glass thimbles are not needed, but do no harm.

That if the repeller be removed, and thepoint on the vanebe terminated as the lightning rods usually are, and then the metal of the lantern be strongly attached to, and connected with, the upper end of the copper rod, and the rod continued down the tower to the earth, and the sheet of copper buried in it, such a system will be an effectual and perfectly safe lightning conductor.

That then there need be no rod end rising by the side of, and above the lantern.

That the rod may (if required on other accounts) come down on the inside of the building, or in a groove in the wall; but should not be unnecessarily removed from observation and inspection.

That all large metallic arrangements in the stonework, or other non-metallic parts of the tower of the lighthouse, such as tying bars, metal flues, &c., should be well connected, by copper, with the conductor.

That the vicinity of two metallic masses without contact, or metallic communication, is to be avoided.

That, as to the South Foreland High Light, the lantern, the central stove, and the copper rod proceeding from it to the earth, connected as they now are, form a perfect lightning conductor, even without the rod that is there erected; but

That it is important casual arrangements should never be depended upon for lightning conductors; but a copper rod be established for the especial purpose: for, if the former be trusted to, the carelessness or ignorance of workmen may, at after periods, upon occasions of repair or cleansing, cause the necessary metallic connection to be left imperfect or incomplete, and then the arrangement is not merely useless but dangerous.

That, as to the Eddystone, it is desirable to connect the system of wrought iron ties in it with the lightning conductor, by joining the lower part of that iron rod which is nearest to the conductor with the latter, by a copper rod or strap, equivalent to the conductor in sectional area.

That the Dungeness Lighthouse is in a very anomalous condition; to rectify which the two repellers should be removed, and also the representative of the top of a lightning rod attached to the flue, and that then a good copper conductor should be attached to the metal of the lantern, upon the principles already expressed.

(Signed.)M. Faraday.

25th September, 1843.

23, Gt. George Street,25th September, 1843.

23, Gt. George Street,

25th September, 1843.

Sir,

The reference, on the important subject of lightning conductors, is to Mr. Faraday and to me. On receiving it I prepared drawings of the buildings to which our immediate attention was required, with an explanation of their present conductors.

These were considered at a meeting with Mr. Faraday, when he explained the principles and their application to the several cases, deduced from his copious experiments and scientific observations.

I have since received from him the accompanying Report for my signature along with his, but the report is altogether Mr. Faraday’s and therefore I prefer adding my approval of all it contains in this separate sheet, and recommending that authority be given to me to act upon it.

I am, Sir, &c.(Signed) J. WALKER.

I am, Sir, &c.

(Signed) J. WALKER.

Jacob Herbert, Esq.Trinity House.

Jacob Herbert, Esq.

Trinity House.

Royal Institution,27th September, 1852.

Royal Institution,

27th September, 1852.

My dear Sir,

I fortunately reached the Nash Low Lighthouse last Thursday, before any repairs were made of the injury caused by the discharge of lightning there, and found everything as it had been left: the repairs were to be commenced on the morrow.

The night of Monday, 30th August, was exceedingly stormy, with thunder and lightning; the discharge upon the lighthouse was at six o’clock in the morning of the 31st, just after the keeper had gone to bed. At the same time, or at least in the same storm, the flag-staff between the upper and lower lights was struck, and some corn stacks were struck and fired in the neighbourhood. It is manifest that the discharge upon the tower was exceedingly powerful, but the lightning conductor has done duty well—has, I have no doubt, saved the building; and the injury is comparatively slight, and is referable almost entirely to circumstances which are guarded against in the report made by myself and Mr. Walker 22nd September, 1843.

The conductor is made fast to the metal of the lantern, descends on the inside of the tower to the level of the ground, and passes through the wall and under the flag pavement which surrounds the tower. It is undisturbed everywhere, but there are signs of oxidation on the metal and the wall at a place where two lengths of copper are rivetted together, which show how great an amount of electricity it has carried.

A water-butt stands in the gallery outside the lantern. A smallcopper pipe, 1 inch in diameter, brings the water from the roof of the lantern into this butt; it does not reach it, but terminates 10 or 12 inches above it. A similar copper pipe conducts the surplus water from the butt to the ground, but it is not connected metallically with the other pipe, or with the metal of the conductor, or the lantern. Hence a part of the lightning which has fallen upon the lantern has passed as a flash, or, as we express it, by disruptive discharge from the outside of the lantern to this tub of water, throwing off a portion of the cement at the place, and has used this pipe as a lightning conductor in the rest of its course to the ground. The pipe has holes made in it in three places, but these are at the three joints, where, it being in different lengths, it is put together with tow and white lead, and where of course the metallic contact is again absent; and thus the injury there (which is very small) is accounted for. The pipe ends below at the level of the ground in a small drain, and at this end a disruptive discharge has (naturally) occurred, which has blown up a little of the cement that covered the place. Some earth is thrown up at the outer edge of the pavement round the tower over the same small drain, which tends to show how intense the discharge must have been over the whole of the place.

Inside of the lantern there are traces of the lightning, occurring at places where pieces of metal came near together but did not touch, thus at the platform where a covering copper plate came near to the top of the stair railing, but the effects are very slight. All the lamps, ventilating tubes, &c., remained perfectly undisturbed, and there was no trace of injury or effect where the conductor and the lantern were united.

Inside of the tower and the rooms through which the conductor passes there were and are no signs of anything (except at the rivetting above mentioned) until we reach the kitchen or living-room which is on a level with the ground, and here the chair was broken and the carpet and oil-cloth fired and torn. To understand this, it must be known that the separation between this room and the oil-cellar beneath is made by masonry consisting of large stones, the vertical joints of which are leaded throughout, so that the lead appears as a network upon the surface, both of the kitchen floor above, and the roof of the oil cellar beneath, varying in thickness in different places up to ⅓ or more of an inch, as in a piece that was thrown out. The nearest part of this lead to the conductor is about 9 inches or a little more distant, and it was here that the skirting was thrown off, and the chair broken; here also that the fender was upset and the little cupboard against the skirting emptied of its articles. If this lead had been connected metallically with the conductor, these effects would not have happened.

The electricity which in its tendency to pass to the earth took this course, naturally appeared in the oil-cellar beneath, and though the greater portion of it was dissipated through the building itself, yet a part appeared in its effects to have been directed by the oil cans, for though they were not at all injured or disturbed, the wash or colour in the wall above four or five of them was disturbed, showing that slight disruptive connections or sparks had occurred there.

At the time of the shock, rain was descending in floods, and the side of the tower and the pavement was covered with a coat of water. This being a good conductor of electricity has shown its effects in connection with the intense force of the discharge. A part of the electricity leaving the conductor at the edge of the pavement and the tower, broke up the cement there, in its way to the water on the surface, which for the time acted to it as the sheet of copper—which I conclude is at the end of the conductor—does,i.e., as a final discharge to the earth. Also on different parts of the external surface of the tower near the ground, portions of cement, the size of half a hand, have been thrown off by the disruptive discharges from the body of the tower to this coat of water: all testifying to the intensity of the shock.

I should state that the keeper says he was thrown out of bed by the shock. However, no trace of lightning appears in the bedroom, still there are evidences that powerful discharges passing at a distance, and on the other side of thick walls may affect bodies and living systems, especially by spasmodic action, and something of the kind may have occurred here. It may be as well for me to state that the upper floors areleadedtogether like that of the kitchen. The reason why they did not produce like effect is evident in that they from their position could not serve as conductors to the earth as the lower course could.

The keeper said he had told the coppersmith to make the necessary repairs in the pipe, and I instructed him to connect the waste pipe and the upper pipe by a flat strap of copper plate. I would recommend that the lead of the lower floor be connected metallically with the conductor to a plate of copper in the earth. I could not see the end of the present conductor, not being able by any tools at the lighthouse to raise the stonework, but I left instructions with the keeper to have it done, and report to me the state of matters.

I am, &c.,(Signed) M. FARADAY.

I am, &c.,

(Signed) M. FARADAY.

The Secretary,Trinity House.

The Secretary,

Trinity House.

Royal Institution,24th January, 1853.

Royal Institution,

24th January, 1853.

My dear Sir,

In reference to the remarkable stroke of lightning which occurred at the Eddystone Lighthouse, at midday on 11th January of this year, and made itself manifest by a partial flash discharge in the living rooms, I have to call your attention to the drawing herewith returned, and to the circumstances which appear (from it) to have accompanied and conduced to the discharge.

In the body of the stone work above the store-room exist eight rings of metal; each going round the building, and each being four inches square of solid iron and lead. Also, latterly the bedroom and sitting-room have been lined with a framework of iron bars, situated vertically, and pinned by long bolts into the stonework.

The part of the tower above the floor of the living-room is, therefore, filled with a metallic system, which, with the metal lantern, gives a very marked character to the upper half of the structure.

The recent metallic arrangements (but not the rings) are connected with the lightning rod; and the copper part of this rod, beginning at the floor of the living-room, then proceeds downwards by the course which can be followed in the drawing, and terminates on the outside of the rock between high and low water marks.

Considering all these circumstances, I was led to conclude that the conductor was in a very imperfect condition at the time of low water; and I had little doubt that I should find that the discharge had taken place when it was in this state, and very probably with a spring tide.

The day of the stroke was the 11th January—a new moon occurred on the 9th, so that it was at a time of spring tide.

The occurrence took place at midday; and, according to the tide tables, that was close upon the time of low water at Devonport. The end of the conductor would then be 6 feet from the water, if the latter were quiescent, and I cannot doubt that this circumstance gave rise to that diverted discharge which became so manifest to the keepers. Mr. Burges, with whom I have conversed about the matter, thinks it probable that, through the violence of the waves, the conductor does not now descend so much as is represented in the drawing.

I think it essential that the lower end of the conductor be made more perfect in its action; and I should prefer this being done on theoutsideof the tower and rock, if the rod can be rendered permanent in such a situation.

If it be impossible to prolong and fix the lower end of the conductor where it now is, so that it shall have large contact with the sea at low water, then I would suggest, whether or no, on the more sloping part of the rock, about midway between high and low water, three or four holes could not be sunk to the depth of 3 feet, and about 3 or 4 feet apart, and that copper rods being placed in these, they should be connected together, and the lightning rod continued to them.

If thiscannotbe done, then it might be right to consider the propriety of the making a hole through the centre of the building and rock, about 2 or more inches in diameter, and 30 feet deep, and continuing the conductor to the bottom.

A conversation with Mr. Burges regarding the present state of the Bishop’s Rock Lighthouse, now in course of construction, induces me also to suggest the propriety of making provision for the lightning conductor as the work proceeds.

It would be easy now to fix terminal rods of copper, and to combine them upwards with the work. Considering the isolated and peculiarly exposed condition of a lighthouse on this site, I would propose that there betwoconducting rods from the lantern, down the outside on opposite sides of the tower, each terminating below in two or three prolongations, entering as proposed into the rock, or into fissures below low water mark, so as to be well and permanently fixed.

I am, &c.,(Signed) M. FARADAY.

I am, &c.,

(Signed) M. FARADAY.

The Secretary,Trinity House.

The Secretary,

Trinity House.

[The present Eddystone Lighthouse, that is the stone one erected in 1757–59 from Smeaton’s designs, has a total height from low water level to the top of the vane of 107 feet. The annexed engraving shows two conductors, the old and defective one passing down the left hand side and terminating half way between high and low water level, and the proposed new one on the right terminating in holes in the rock.—Ed.]

Eddystone.

[The following letter would have been placed in Appendix A. along with the replies from British Manufacturers of Lightning Conductors; but it did not arrive until long after they had been printed off.—Ed.]

Please find enclosed answer to your questions. In addition to manufacturing rods, we have been protecting buildings with these rods for thirty years. We sell in this way at retail from five to six hundred thousand feet each year. We also issue a guarantee of $500 (£100) on each building that we protect, which we hold ourselves ready to make good in case of failure. Now, in this extensive business, we have only had to pay one dollar damage done by lightning. We regard this as a practical demonstration that our method of protecting buildings with iron rods is as near perfect as it can be. There is more profit to be made out of the copper rod, as it is made cheaply out of sheet copper, and can be sold much higher than the iron rod. But knowing that iron for all practical purposes is the best material for lightning rods, we feel it to be our duty to do all we can to introduce it. We would most respectfully ask the Conference to investigate this question as to what kind of metal is best for rods for practical use, iron or copper. Our own late Professor Joseph Henry pronounced in favour of iron. We have many facts in relation to buildings being struck by lightning which we could give at some future time if desired. We have gathered up a large number of points that have been melted by lightning strokes. They are melted down about ½ inch. They all look as if the same amount of heat had been applied to each, showing very clearly that the quantity of electricity in lightning strokes is quite uniform. We have never in any instance known of the rod being melted, showing that the rod which we use is of sufficient size.

1 & 2. We make spiral twisted iron rods weighing 45 lbs. to the hundred feet [7¼ oz. per foot]. The rod is of the same sized material throughout its length, except that a copper point, plated with silver and tipped with platinum, is screwed on the upper terminal.

3. No proportion is observed between the length and sectional area.

4. Joints are made by means of copper nuts.

5. Attached to building by means of zinc strips, or a casting that fits closely to the rod, which is screwed down.

6. The rod extends from 9 to 10 feet in the ground.

7. A circle twice the diameter of height of rod above roof.

8. All terminals on the roof are connected. There are never less than two ground rods, and these are increased as the number of upper terminals are increased.

We also manufacture copper rods, but do not use them where we protect buildings, nor do we recommend them to other dealers from the fact that our experience of thirty years has demonstrated that iron is the best material for lightning rods.

COLE BROTHERS.

Mount Pleasant,Iowa, United States.

Mount Pleasant,

Iowa, United States.

A colliery chimney near Sunderland, 180 feet high, was struck by Lightning, November 13th, 1878, and I was sent for to repair it. Upon getting to the top, which was about 15 feet diameter, I found a great many of the bricks displaced, and the upper terminal of the conductor (which was a tube 0·50 in. internal, and about 0·62 in. external diameter, and which had stood about 1 foot above the top of the chimney) had been fused and was lying on the top of the chimney, it was quite brittle, and easily broken by the hand. The upper 10 feet of ½ inch wire rope was in a similar state; it seemed as if it had been passed through an exceedingly hot furnace, and I rubbed it to dust in my hands. This 10 feet length was above the first holdfast, below the holdfast the wire rope was perfectly good. The holdfast was one of those which are driven into a wooden plug let into the wall and pinned tightly down on the rope, which had been badly bruised in the fixing—in fact, knocked almost flat. I believe that this was the cause of the accident, and that the lightning travelled down as far as this holdfast, and there meeting obstruction, returned destroying the wire and rod and shattering the brickwork. The earth connection was good, the end was buried in a trench 2 feet deep and 15 feet long.

T. MASSINGHAM.

Newcastle-on-Tyne.

I have been in communication with several of the principal brick builders here by whom the great majority of the chimney stalks in Glasgow and the west of Scotland are erected, and I believe the following statements may be taken as correct:—

(1) Very few stalks under ninety feet in height have lightning conductors, but,as a rule, the higher stalks have conductors. One of my correspondents says that “this rule holds good in four cases out of five.”

(2) A chimney being struck by lightning is an extremely rare occurrence in this district. One builder of long experience (Mr. McDonald) says, “I have known of several stalks that were struck by lightning, that had no conductors. I cannot point to one that was struck by lightning and had a conductor.” Another firm of old standing (Allan and Mann) say—“In our experience we have not known of a chimney stalk, with lightning conductor fixed, damaged by lightning.” Another firm (Bell, Hornsby and Co.) say—“In our experience we have not known an ordinary stalk with or without a conductor struck by lightning,” and Mr. Goldie says—“During the last twenty years I can remember only one such case,” and he is not sure whether the stalk had a conductor or not. There are three cases known to have occurred in Glasgow, but I never heard of any others among the hundreds—I may say thousands—of chimneys which are here. The great stalk at St. Rollox was struck shortly after its erection. A stalk at the works of Messrs. Alexander Paul and Co., was struck about nine years ago. Mr. Goldie makes theremark—and I think it is well worthy of notice—that in all these cases the accident happened shortly after the completion of the stalk. In these circumstances the stalk would still, no doubt, contain a large amount of moisture.

I think the St. Rollox stalk had a conductor fixed before it was struck, but I am not aware whether either of the others had.

Mr. Higginbotham (Todd and Higginbotham) tells me that the stalk at their works was struck before it was quite completed. It wasvery slightlyinjured. It was afterwards struck as mentioned in my letter. On that occasion it had a lightning conductor.

The damage done was not very serious, but necessitated the binding of the stalk with numerous iron hoops—as thus strengthened it still stands. Mr. Higginbotham says that the opinion at the time was that the conductor saved the stalk from complete destruction, but that it was too small.

They, therefore, had it replaced by a much heavier one—copper rope ⅜th of an inch diameter, kept 1½ inches from the brickwork by glass insulators—which still remains.

J. HONEYMAN.

140, Bath Street, Glasgow.

There was no lightning conductor of any kind at Wells Church. The electric fluid struck the east side of the Tower just above the ridge of the nave roof. The tower stands, or stood, at the west end. I enclose an account of the fire from a local paper:—

Wells.—Total Destruction of the Church.—“Near midnight of Saturday last, August 2nd, 1879, a terrific thunderstorm burst over this town and a large district around, causing most intense alarm and unfortunately ending in sad disaster. The storm raged throughout the night, and was accompanied in many places by a perfect deluge of rain. Between three and four a.m. of Sunday, the 3rd, it appeared to reach its height, the lightning being of a most vivid and alarming nature, and the thunder reverberating in continuous peals. A lull then occurred, but between five and six a.m. the storm again burst out with great fury, and at 5.50 the electric fluid struck the church on the eastern face of the tower immediately above the apex of the roof, driving out a large portion of the stone work, the flints flying hundreds of feet around. One large stone fell upon the roof of a house, near the east window, and penetrated to the room below, which was fortunately unoccupied; but the tenant, Mr. R. Wharf, who slept in the next room, was aroused, and one or two persons in the road seeing what had occurred, and observing smoke directly after issuing from the roof of the church, raised an alarm of fire, which quickly awakened the whole town.

R. M. PHIPSON.

Norwich.

The first visible injury to Wells Church was the “skinning” of a portion of the tower (about 10 feet high by 5 feet broad) extending downwards from the east window of the tower (i.e., the window which looked over the roof of the nave,) to the point at which the lead-covered nave joined the tower. The lightning is believed to have set fire to the roof at this point, and also to have travelled along the lead roof to the chancel, and in crossing the vestry to have ignited the surplices, as the church was seen to be on fire at both ends before the middle was touched. The “skinning” was accompanied by great disruptive force, as the stones from the tower were not only shot the full length of the church, but one large one fell on the roof of a house 60 feet beyond the east end of the church.

Wells, Norfolk.

F. LONG.

As your questions in theTimesof to-day allude only to protection tobuildingsfrom lightning, I need not say anything on the perfect protection afforded to Her Majesty’s ships by the conductors of Sir Snow Harris, from the time they were used in every ship in the service.

H.M.S. “Beagle,” Commander FitzRoy, was one of the first ships fitted with them. At Monte Video a heavy shock of lightning passed down the mainmast and through the ship without doing the slightest injury; but as the vane staff which tapered to a fine point, was fused at the point, it enables me to answer one of your questions. The copper was melted till the diameter was about one eighth of an inch, but below that point the conductor was not injured in any way.

You will like to know a case in which a copper wire acted as a perfect conductor,though fused throughout its length. It was at Monte Video, in the house of the English Consul, a flag-staff was struck, and conducted the lightning through a flat roof, near the bell wire of a suite of rooms (the wire ran in sight near the cornice) through a hole in each dividing wall, and then down to the bell in the basement; the wire was melted into drops like shot, which burnt a row of small holes in the carpet of each room. A dark mark, on the cornice above, showed where the wire had been. At the bell there was a slight explosion, and some little damage, but I do not recollect whether anything acted partially as a conductor from that point, and so carried off that part of the charge.

This, I think, shows that even an ordinary bell wire will act as a conductor for a rather strong stroke of lightning, as the large flag-staff was shattered.

I am anxious to call the attention of your conference to a point that it will be interesting to clear up. That is, whether a conductor should be asolidrod, or in a shape to give the largest amount ofsurfacein the section? When I tell you that Faraday and Harris each told me that the other “knew nothing about it,” because they differed entirely on this point, I think you will see the importance of it. I had at the time to approve of the conductors for lighthouses. I will, if you wish it, give you more particulars on this point, as Ibelieve it has never yet been settled: lighthouses having been fitted with Faraday’s, and ships and public buildings with Harris’ conductors. The one being a solid bolt, the other a hollow tube or double thin plates.

If Harris was right there is an unnecessary amount of copper in Faraday’s solid conductors; if Faraday is right, there is an unnecessary outlay in putting a given amount of copper into the shape of a tube, instead of using it as a solid rod.

B. J. SULIVAN,Admiral.

P.S.—You should get from the Trinity House particulars of a case in which, with a good solid conductor, the iron floor of a lighthouse, aided by some lead in the wall, diverted the lightning from the conductor, and caused damage inside. I think it was a Portland lighthouse, but it is so many years since that I may not be right.

Tregen, Bournemouth.

Three or four years since, I was looking out of my office window in Finsbury, when a flash of lightning struck the tower of the church of St. Giles’, Cripplegate, towards which my sight happened at the time to be directed. As a portion only of the flag-staff, placed at one corner of the tower, was destroyed, I obtained permission to ascend the tower and discover the reason. I found a substantial copper rope conductor fixed in a somewhat careless fashion to the back of the tower, and passing some distance into the earth. This copper rope was about an inch in diameter, and was carried upwards, under and over several projections and cornices, and across the roof of the tower to its centre—where it stood erect, and evidently did its assigned work admirably. Clumsy and unsatisfactory as the fixing of this bent copper rope seemed to me to be, it is quite certain that it was most efficient; and had it not been for the flag-staff, capped with lead, which was carried up considerably higher than the copper rope, no evidence whatever of the lightning’s path would have been revealed. As it was, the discharge of lightning struck the leaden cap of the flag-staff, and descended down the wet, wooden pole, until the summit of the copper-rope conductor in the centre of the tower was reached, when the discharge flew across to the metallic earth conductor, leaving the lower part of the flag-staff unhurt, but shattering to splinters that portion which was higher than the summit of the copper rope.

RICHARD HERRING.

27, St. Mary’s Road, Highbury.

A small public-house of mine (the “Wheatsheaf”) stands at Trolley Bottom, in the parish of Flamstead, between St. Albans and Dunstable. On Wednesday, August 6th, 1879, about 2 p.m., during a storm, not otherwise very severe, my tenant was seated by the tap-room window (A on the plan) his wife being seated opposite to him, and having the window on her left, whilst she held her childwith her right hand; there were at the same time in the room about five men besides. A sharp flash of lightning occurred, and the poor woman (when the smoke cleared away) was observed to have fallen backwards. She gasped twice, never spoke, and died immediately, and bore no further mark of injury, I understand, than a slight mark as of scorching on her neck, below the left ear. I fail to recollect whether her clothing was scorched or not, the child’s shoe and sock were both burnt, but she, herself, was unharmed. All present were sensible of an atmosphere heavily laden with sulphurous fumes; but, excepting as above, were absolutely unhurt.

On visiting the house about a week afterwards, with a view to its repair, I found a small round hole as if made with a bullet in a pane of the window (A) close to which the woman was sitting, but could discover no further injury either to the other panes, the window-frame, the floor, or anything in the room. In the parlour, B, the window-frame was violently wrenched outwards two or three inches, several of the panes were broken, one sash-line being scorched, as also the frame and linings in places, especially in the neighbourhood of the sash-weights (iron). The wooden chimney-piece E, was slightly moved from its position, the various articles upon it were scattered, and a bottle of ink which stood there, was thrown with some violence to the ceiling. The upper part of the chimney to that room, G, and a portion of the wall, of which it was a part, forming the gable end to the house were shattered, and at H a stout post, contiguous to the house wall, and supporting the roof of a lean-to, was split and wrenched from its position. The windows and frames upstairs, C D, were in the same state as that at B. The chimney, K, to the tap-room, was quite uninjured, and no harm was done to any part of the back of the house.

ELEVATION. PLAN.

Flamstead is about four miles from Luton, and six from St. Albans, and stands on high land. Trolley Bottom is a hamlet half-a-mile distant, and is, as its name implies, low-lying. My house is, perhaps, the lowest in position there. It faces the North-West.

I fear that my experiences will be found to have but little bearing upon the main point you have in view, viz., the comparative merits of different descriptions of Lightning Conductors. I venture to think, however, that they are not altogether without interest as illustrating the effects of lightning in a by no means exposed situation.

I am writing only from memory what was told me at the time, and should you desire further information on any points, shall be happy to endeavour to obtain it for you.

It would interest me very much to know how it is to be accounted for that, whilst in the room in which the poor woman was struck, no further damage was done, other parts of the house were, comparatively speaking, wrecked.

JOHN EDWARD GROOME.

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