Experiments concerning the different efficacy of pointed and blunted rods, in securing buildings against the stroke of lightning / [William Henley].

  • Henley, William.
Date:
1774
Catalogue details

Licence: Public Domain Mark

Credit: Experiments concerning the different efficacy of pointed and blunted rods, in securing buildings against the stroke of lightning / [William Henley]. Source: Wellcome Collection.

    19/34 (page 15)
    [ J5 ] ** electrometer. In this manner, I exhaufted the? 44 battery, without any fenfible diminution, or de- 44 ftru&ion, of the gold leaf. Whereas a greater 44 quantity of leaf gold may be diffipated, by a; 44 ftroke from a Angle fmall jar, if put under one* 44 of the knobs of the difcharging rod, and the 44 ftroke be invited by the other; for in fuch cafe,, 44 the leaf gold cannot, in any manner, adt like a 44 point. 44 Now as bodies adt at a greater diffance, by 44 how much they are more acute, and thereby 44 diminifti any known eledtrical force ; and, as in 44 any particular cafe, the fmallnefs of the pencil,. 44 or ftroke, depends on the acutenefs of the point 44 prefented, I cannot avoid giving my fuffrage 44 for points, in preference to obtufe bodies. It may not, I think, be improper to introduce,, in this place, an experiment lately made by Mr. edward N air ne, in Corn hill; which, though it doth not immediately relate to the particular fubjedt* of this paper, is a very proper one to de~ monftrate the. utility of metallic conductors In, MR. NAIRNe's EXPERIMENT.. Fie affixes,, in a little apparatus refembling the hulk of a (hip, a glafs tube, about eight inches long, and half an inch in diameter, which is to reprefent the main-maft. The ends of the tube,, which.is* filled with water, are properly fe- cured by corks; and, through each cork, a wire is in trod need,, of fuch a length as to reach nearly