Abbildungen der Seite
PDF
EPUB

dans le moment de l'expérience de ce que je voyois, qu'ayant été frappé au bras un peu au-dessus du coude, je ne puis dire si c'est en touchant au fil d'archal ou à la tringle; je ne me suis pas plaint du mal que m'avoit fait le coup dans le moment que je l'ai reçu ; mais comme la douleur continuoit, de retour chez moi, j'ai découvert mon bras en présence de Coiffier, et nous avons apperçu une meurtrissure tournante autour du bras, semblable à celle que feroit un coup de fil d'archal, si j'en avois été frappé à nud. En revenant de chez Coiffier, j'ai rencontréM. le Vicaire, M. de Milly, et le Maître d'école, à qui j'ai rapporté ce qui venoit d'arriver; ils se sont plaints tous les trois qu'ils sentoient une odeur de soufre qui les frappoit davantage à mesure qu'ils s'approchoient de moi; j'ai porté chez moi la même odeur, et mes domestiques s'en sont apperçus sans que je leur aie rien dit.

“Voilà, Monsieur, un récit fait à la hâte, mais naïf et vrai, que j'atteste, et vous pouvez assurer que je suis prêt à rendre témoignage de cet événement dans toutes les occasions. Coiffier a été le premier qui a fait l'expérience et l'a répétée plusieurs fois; ce n'est qu'à l'occasion de ce qu'il a vu qu'il m'a envoyé prier de venir. S'il étoit besoin d'autres témoins que de lui et de moi, vous les trouveriez. Coiffier presse pour partir.

“ Je suis, avec une respectueuse considération, Monsieur, votre, &c.

) “RAULET, Prieur de Marly. “10 Mai, 1752."

On voit, par le détail de cette lettre, que le fait est assez bien constaté pour ne laisser aucun doute à ce sujet. Le porteur m'a assuré de vive voix qu'il avoit tiré pendant près d'un quart-d'heure avant que M. le Prieur arrivât, en présence de cinq ou six personnes, des étincelles plus fortes et plus bruyantes que celles dont il est parlé dans la lettre. Ces premières personnes, arrivant successivement, n'osoient approcher qu'à dix ou douze pas de la machine; et à cette distance, malgré le plein soleil, ils voyoient les étincelles et entendoient le bruit. .....

asse

Il résulte de toutes les expériences et observations que j'ai rapportées dans ce mémoire, et surtout de la dernière expérience faite à Marly-la-ville, que la matière du tonnerre est incontestablement la même que celle de l'électricité. L'idée qu'en a eu M. Franklin cesse d'être une conjecture; la voilà devenue une réalité, et j'ose croire que plus on approfondira tout ce qu'il a publié sur l'électricité, plus on reconnoîtra combien la physique lui est redevable pour cette partie.

THE ABBÉ MAZÉAS TO STEPHEN HALES.*

Giving a further Account of the Electrical Experiment

at Marly.

READ AT THE ROYAL SOCIETY, MAY 28TH, 1752.

SIR, The Philadelphian experiments, that Mr. Collinson, a member of the Royal Society, was so kind as to communicate to the public, having been universally admired in France, the King desired to see them performed. Wherefore the Duke d’Ayen offered his Majesty his country-house at St. Germain, where M. de Lor, master of experimental philosophy, should put

* The early letters of Dr. Franklin on electricity having been translated into French, and printed at Paris, the Abbé Mazéas, in a letter to Dr. Stephen Hales, dated St. Germain, May 20th, 1752, gives the above account (printed in the Philosophical Transactions ") of the experiment made at Marly, in pursuance of that proposed by Mr. Franklin.

[ocr errors]

those of Philadelphia in execution. His Majesty saw them with great satisfaction, and greatly applauded Messieurs Franklin and Collinson. These applauses of his Majesty having excited in Messieurs de Buffon, Dalibard, and de Lor a desire of verifying the conjectures of Mr. Franklin, upon the analogy of thunder and electricity, they prepared themselves for making the experiment.

M. Dalibard chose for this purpose a garden, situated at Marly, where he placed upon an electrical body a pointed bar of iron, of forty feet high. On the 10th of May, twenty minutes past two in the afternoon, a stormy cloud having passed over the place where the bar stood, those that were appointed to observe it, drew near and attracted from it sparks of fire, perceiving the same kind of commotions as in the common electrical experiments..

M. de Lor, sensible of the good success of this experiment, resolved to repeat it at his house in the Estrapade, at Paris. He raised a bar of iron ninety-nine feet high, placed upon a cake of resin, two feet square, and three inches thick. On the 18th of May, between four and five in the afternoon, a stormy cloud having passed over the bar, where it remained half an hour, he drew sparks from the bar, like those from the gunbarrel, when, in the electrical experiments, the globe is only rubbed by the cushion, and they produced the same noise, the same fire, and the same crackling. They drew the strongest sparks at the distance of nine lines, while the rain, mingled with a little hail, fell from the cloud, without either thunder or lightning; this cloud being, according to all appearance, only the consequence of a storm, which happened elsewhere." I am, with a profound respect, Your most humble and obedient servant,

G. Mazkas.

TO PETER COLLINSON.

Electrical Kite.
READ AT THE ROYAL SOCIETY, DECEMBER 21st, 1752.

Philadelphia, 19 October, 1752. SIR, As frequent mention is made in public papers from Europe, of the success of the Philadelphia experiment for drawing the electric fire from clouds by means of pointed rods of iron erected on high buildings, &c., it may be agreeable to the curious to be informed, that the same experiment has succeeded in Philadelphia, though made in a different and more easy manner, which is as follows.

Make a small cross of two light strips of cedar, the arms so long as to reach to the four corners of a large thin silk handkerchief when extended; tie the corners of the handkerchief to the extremities of the cross, so you have the body of a kite; which, being properly accommodated with a tail, loop, and string, will rise in the air, like those made of paper; but this being of silk is fitter to bear the wet and wind of a thundergust without tearing. To the top of the upright stick of the cross is to be fixed a very sharp-pointed wire, rising a foot or more above the wood. To the end of the twine, next the hand, is to be tied a silk ribbon, and where the silk and twine join, a key may be fastened. This kite is to be raised when a thunder-gust appears to be coming on, and the person who holds the string must stand within a' door or window, or under some cover, so that the silk ribbon may not be wet; and care must be taken that the twine does not touch the frame of the door or window. As soon as any of the thunder-clouds come over the kite, the pointed wire will draw the electric fire from them, and the kite, with

all the twine, will be electrified, and the loose filaments of the twine will stand out every way, and be attracted by an approaching finger. And when the rain has wetted the kite and twine, so that it can conduct the electric fire freely, you will find it stream out plentifully from the key on the approach of your knuckle. At this key the phial may be charged; and from electric fire thus obtained, spirits may be kindled, and all the other electric experiments be performed, which are usually done by the help of a rubbed glass globe or tube, and thereby the sameness of the electric matter with that of lightning completely demonstrated.

B. FRANKLIN.

FROM W. WATSON* TO THE ROYAL SOCIETY.

Concerning the Electrical Experiments in England upon

Thunder-clouds.

READ AT THE ROYAL SOCIETY, DECEMBER

GENTLEMEN, After the communications, which we have received from several of our correspondents in different parts of the continent, acquainting us with the success of their experiments last summer, in endeavouring to extract the electricity from the atmosphere during a thunderstorm, in consequence of Mr. Franklin's hypothesis, it may be thought extraordinary, that no accounts have been yet laid before you, of our success here from

* A member of the Royal Society, and afterwards Sir William Watson. He was distinguished for his great acquirements in botany, and other natural sciences, and particularly for his experiments and discoveries in electricity.- EDITOR.

« ZurückWeiter »