A letter from Paris concerning some new electrical experiments made there / [John Turberville Needham].

  • John Needham
Date:
1746
Catalogue details

Licence: Public Domain Mark

Credit: A letter from Paris concerning some new electrical experiments made there / [John Turberville Needham]. Source: Wellcome Collection.

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    from rhe college of Havccurt, to his apartments in the king*s garden, without any very fenfible diminution of its efficacy. The ufe of the eledtrified phial may be diverfified many ways: among others are fuch as follow. Exp. the $th. When the phial has been Efficiently eledtrified as above, the whole company join hands *, the operator at one extremity of the line grafps the bottom of the electrified phial, and the perfon at the other extremity touches the wire, which’ rifes above the cork. At that inftant, the whole company receives a fhock, re- fembling that in the experiment of the gun-barrel, but not fo ftrong; for it feems not at all to extend beyond the elbows. This is the experiment, which mon- fieur le Monnier performed upon 180 of the guards, before the king, who were all fo fenfible of it at the fame inftant of time, that the furprize caufed them all to fpring up at once, as it will indeed force any perfon to do that fubjedts himfelf to the trial, tho’ the convulfionary motion itfelf, as I obferved before, reaches not beyond the elbows: but the greater or leffer effedl depends entirely upon the longer or ffiorter application of the phial to the eledlrifying Ipheroid, and I am credibly informed, that when due precautions have not been taken in this particular, fome perfons have received fuch violent fhocks, as have be¬ numbed, and impaired to a certain degree, the ufe of their arms for a day or two, before they perfectly recovered themfelves. I can aflure you, however, from my own experience, that, with the precautions I have already taken notice of, there is no manner of danger, at the fame time that a Efficient efficacy may be communicated to the phial, to gratify any one’s curiofity : and in this parti¬ cular, I have been the more prolix, left any bad confequence fhould happen to the unexperienced. — A 6th experiment with the eledtrified phial confifts, firft, in placing a wire fixed in a pedeftal, eredlin a bafon of water, the head of which wire is bent, and rifes fome three or four inches above the level of the water ♦, and then, in touching the furface of the water with one hand, and the Handing wire with the wire of the electrified phial, which is grafped by the other hand, as in the preceding experiments: the effeCt of this is much more violent than that of the laft experiment, and I think, exceeds even the fhock of the gun-barrel; fo that here the utmoft precaution muft be ufed, not to eledtrify the phial too much. I obferved particularly upon the trial of this, that the operator who appeared to be very expert, and quite familiarized with.every effedl, fhewed however fome apprehenfion, and was unwilling to lead the way, as he had done in all the other experiments. Exp. the yth. If the eledtrified phial be held in the hand, and the chamber is darkened, the wire inferted in it, is perceived to emit a ftream of fire at its extremity without any difcontinuance but if it be fufpended by a filken thread, the fiery eruption inftantly ceafes. This, as a per¬ fon would be apt to imagine, gives fome in fight into the reafon of its retention of eledlricity, the ambient glafs and filken thread, being in the number of the eledtrics per fe, which have a power of determining to, and confining in, any other kind of body, a communicated eledlricity, though they are not fufceptible of it themfelves. Yet as the French obferve very well, there are fo many of what they term bizarreries, or unaccountable phenomena, in the courfe of elebtrical experiments, that a man can fcarce aflert any thing in confequence of
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