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The lower end of the rod should enter the earth so deep as to come at the moist part, perhaps two or three feet; and, if bent when under the surface so as to go in a horizontal line six or eight" feet from the wall, and then bent again downwards three or four feet, it will prevent damage to any of the stones of the foundation.

A person apprehensive of danger from lightning, happening during the time of thunder to be in a house not so secured, will do well to avoid sitting near the chimney, near a looking-glass, or any gilt pictures or wainscot; the safest place is in the middle of the room (so it be not under a metal lustre suspended by a chain), sitting in one chair and laying the feet up in another. It is still safer to bring two or three mattresses or beds into the middle of the room, and, folding them up double, place the chair upon them ; for they not being so good conductors as the walls, the lightning will not choose an interrupted course through the air of the room and the bedding, when it can go through a continued better conductor, the walls. But, where it can be had, a hammock or swinging bed, suspended by silk cords equally distant from the walls on every side, and from the ceiling and floor above and below, affords the safest situation a person can have in any room whatever; and what, indeed, may be deemed quite free from danger of any stroke by lightning.

BER B . FRANKLIN.

[graphic]

FROM JOHN WINTHROP TO BENJAMIN FRANKLIN.

St. Bride's Steeple.

. Cambridge, 6 January, 1768. ..... I HAVE read in the Philosophical Transactions the account of the effects of lightning on St. Bride's steeple. It is amazing to me, that, after the full demonstration you had given, of the identity of lightning and of electricity, and the power of metalline conductors, they should ever think of repairing that steeple without such conductors. How astonishing is the force of prejudice, even in an age of so much knowledge and free inquiry!

TO JOHN WINTHROP.

On Conductors for protecting Houses from Lightning.

Singular Kind of Glass Tube.

London, 2 July, 1768. DEAR SIR, You must needs think the time long that your instruments have been in hand. Sundry circumstances have occasioned the delay. Mr. Short, who undertook to make the telescope, was long in a bad state of health, and much in the country for the benefit of the air. He however at length finished the material parts that required his own hand, and waited only for something about the mounting, that was to have been done by another workman; when he was removed by death. I have put in my claim to the instrument, and shall obtain it from the executors as soon as his affairs can be settled. It is now become much more valuable than it would have been if he had lived, as he excelled all others in that branch. The price agreed for was one hundred pounds. The equal altitudes and transit instrument was undertaken by Mr. Bird, who doing all his work with his own hands for the sake of greater truth and exactness, one must have patience that expects any thing from him. He is so singularly eminent in his way, that the commissioners of longitude have lately given him five hundred pounds merely to discover and make public his method of dividing instruments. I send it you herewith. But what has made him longer in producing your instrument is, the great and hasty demand on him from France and Russia, and our Society here, for instruments to go to different parts of the world for observing the next transit of Venus; some to be used in Siberia, some for the observers that go to the South Seas, some for those that go to Hudson's Bay. These are now all completed, and mostly gone, it being necessary, on account of the distance, that they should go this year to be ready on the spot in time. And now, he tells me, he can finish yours, and that I shall have it next week. Possibly he may keep his word. But we are not to wonder if he does not. Mr. Martin, when I called to see his panopticon, had not one ready; but was to let me know when he should have one to show me. I have not since heard from him, but will call again. Mr. Maskelyne wishes much that some of the governments in North America would send an astronomer to Lake Superior, to observe this transit. I know no one of them likely to have a spirit for such an undertaking, unless it be the Massachusetts, or that have a person and instruments suitable. He presents you one of his pamphlets, which I now send you, together with two letters from him to me, relating to that observation. If your health and strength were sufficient for such an expedition, I should be glad to hear you had undertaken it. Possibly you may have an élève that is capable. The fitting you out to observe the former transit, was a public act for the benefit of science, that did your province great honor.

We expect soon a new volume of the Transactions, in which your piece will be printed. I have not yet got the separate ones which I ordered.

It is perhaps not so extraordinary that unlearned men, such as commonly compose our church vestries, should not yet be acquainted with, and sensible of, the benefits of metal conductors in averting the stroke of lightning, and preserving our houses from its violent effects, * or that they should be still prejudiced against the use of such conductors, when we see how long even philosophers, men of extensive science and great ingenuity, can hold out against the evidence of new knowledge, that does not square with their preconceptions; and how long men can retain a practice that is conformable to their prejudices, and expect a benefit from such practice, though constant experience shows its inutility. A late piece of the Abbé Nollet, printed last year in the Memoirs of the French Academy of Sciences, affords strong instances of this ; for, though the very relations he gives of the effects of lightning in several churches and other buildings show clearly, that it was conducted from one part to another by wires, gildings, and other pieces of metal, that were within or connected with the building, yet in the same paper he

. * Alluding to the preceding letter from Professor Winthrop, respecting St. Bride's steeple. - EDITOR.

VOL. v.

objects to the providing metalline conductors without the building, as useless or dangerous.* He cautions people not to ring the church bells during a thunderstorm, lest the lightning, in its way to the earth, should be conducted down to them by the bell-ropes,t which are but bad conductors; and yet is against fixing metal rods on the outside of the steeple, which are known to be much better conductors, and which it would certainly choose to pass in, rather than in dry hemp. And, though for a thousand years past, bells have been solemnly consecrated by the Romish Church, in expec

* “Notre curiosité pourroit peut-être s'applaudir des recherches qu'elle nous a fait faire sur la nature du tonnerre, et sur la mécanisme de ses principaux effets, mais ce n'est point ce qu'il y a de plus important; il vaudroit bien mieux que nous puissions trouver quelque moyen de nous en garantir; on y a pensé ; on s'est même flatté d'avoir fait cette grande découverte; mais malheureusement douze années d'épreuves et un peu de réflexion nous apprennent qu'il ne faut pas compter sur les promesses qu'on nous a faites. Je l'ai dit, il y a long temps, et avec regret, toutes ces pointes de fer qu'on dresse en l'air, soit comme électroscopes, soit comme préservatifs, sont plus propre à nous attirer le feu du tonnerre qu'à nous en préserver; et je persiste à dire que le projet d'épuiser une nuée orageuse du feu dont elle est chargée, n'est pas celui d'un physicien.” — Mémoire sur les Effets du Tonnerre.

f “Les cloches, en vertu de leur bénédiction, doivent écarter les orages et nous préserver des coups de foudre ; mais l'église permet à la prudence humaine le choix des momens ou il convient d'user de ce préservatif. Je ne sais si le son, considéré physiquement, est capable ou non de faire crever une nuée, et de causer l'épanchement de son feu vers les objets terrestres ; mais il est certain et prouvé per l'expérience, que le tonnerre peut tomber sur un clocher, soit que l'on y sonne ou que l'on n'y sonne point; et si cela arrive dans le premier cas, les sonneurs sont en grand danger, parcequ'ils tiennent des cordes par lesquelles la commotion de la foudre peut se communiquer jusqu'à eux; il est donc plus sage de laisser les cloches en repos quand l'orage est arrivé au-dessus de Péglise." - Ibid.

| Suivant le rituel de Paris, lorsqu'on bénit des cloches, on récite les oraisons suivantes.

“ Benedic, Domine, ...., quotiescumque sonuerit, procul recedat virtus insidiantium, umbra phantasmatis, incursio turbinum, percussio fulminum, læsio tonitruum, calamitas tempestatum, omnisque spiritus procellarum," &c.

" Deus, qui per beatum Moïsen, &c., ..... procul pellentur insidie

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