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.

    25/34 (page 21)
    [«] upon the conductors on St. paul*s cathedral, were not the efFeCts of lightning, but proceeded from, very different caufes. I have made many other experiments on the different effeCt of knobs or points, as oppofed to initiated electrified bodies; but as they all con¬ cur, in eftablifhing and confirming the opinions; before advanced, it feems unneceffary to men-« tion them ; and the more fo, as I believe thofe already recited will be deemed fufficiently de,<* cifive without them.. Having now finifhed what I had to offer,, upon the fubjeCt of pointed conductors, as being the rnoft proper for the fecurity of buildings, &c. I fliall add, by way of appendix, a very curious obfervation, relating to perfonal fecurity, which; I find like wife among thofe of the learned Pro- feffor winthrop,' communicated to me by Dr., franklin. This gentleman, having remarked, that people ftanding in an open plain, are by no means fecure from a ftroke of lightning, advifes thofe, who may be overtaken by a ftorm, in fuch a fituation, to retire within fome fmali diftance, as from thirty or forty, to ten or fifteen feet, of an high tree (perhaps about fifteen or twenty feet from the outermoft branches, m§y be as proper a diftance as any) or. rather two fuch, if at hand, and there wait the event,, but by no means to go under them. This advice will, 1; believe, be acknowledged to be mod judicious^, and, if properly attended to, may be of great for vice.