Observations on a series of electrical experiments / By Dr Hoadly, and Mr Wilson.

  • Benjamin Hoadly
Date:
1756
Catalogue details

Licence: Public Domain Mark

Credit: Observations on a series of electrical experiments / By Dr Hoadly, and Mr Wilson. Source: Wellcome Collection.

    35/80 page 31
    . [ 3* ] Every one knows that a bar of iron, fufpended by filk firings in the air, may be kept equally eledtrified, or very nearly fo, for any length of time, by the eledtrify- ing machined being kept equally in motion, during that time. Now if inflead of approaching an excited tube of glafs (which is continually lofing its power) to the ex¬ haufted tube, as I did before; I now approach the exhaufted tube to the excited bar (whofe force is conftantly kept up at the fame degree by the machine) to fuch a particu¬ lar dijftance, as to make the lucid appearance begin; and then keep it there fteady: I gain this advantage, that it continues during the whole time I keep it thus fteady at one certain diflance, expofed to one and the fame de¬ gree of force in the excited bar, or very nearly fb. And on trying the experiment thus, I found that the lucid appearance continues only for a limited time; and if the tube was to be held fo ever fo long, there would be no return of that appearance; but on removing the exhaufted tube from the bar, the light returns again immediately, fhooting then from the brafs and hand to that part of the inner furface of the tube, that had been neareft to the bar. No experiment can be flronger to the point, than this; and we may now fairly conclude, that the eledtrical fluid does not flow in fo plentifully, or fo forcibly as to reach the inner furface of the glafs, and fo fupply it with a quantity equal to what is thrown off through it into
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