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

  • Benjamin Hoadly
Date:
1759
Catalogue details

Licence: Public Domain Mark

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

    30/96 (page 26)
    brafs, fo that the tube may be readily fixt to the air- pump and exhaufted of air 3 and afterwards removed from it, and ft ill remain exhaufted. i° Let this tube be fixt to the air-pump in order to be exhaufted of air. Now before this is done, the outer and inner furface of the glafs tube are equally expofed to the air 5 and confequently, the powers of thefe two furfaces are in equilibrio, even fuppofing the air to affedt them. 2° Let the tube be exhaufted of air, as perfedtly as it can. When this is done, the outer furface remains, as be¬ fore, expofed to the air j and the inner furface is ex¬ pofed to the eledtrical fluid, which I will fuppofe to be naturally difperfed in empty fpaces void of all grofs bo¬ dies, (as the vacuum is thought very nearly to be) as well as in the pores of grofs bodies. And the equilibrium is ftill preferved between the powers at thefe furfaces : as we may conclude from there being no vifible or perceptible alterations obferved to be produced on drawing the air out of the hollow of the tube, either in the light, or in the dark. Whence we may conclude that the air, when it has its natural quantity of this eledtrical fluid only in it, does not affedt this tube at its outer furface, more than the fluid within it does at its inner furface. 30 Let the exhaufted tube be taken off the air-pump: and let a perfon grafp the hrafs end of it with his hand, whilft he ftands on the ground* 4°