File:The panorama of science and art (1823) (14597422469).jpg

Identifier: panoramaofscienc02smit (find matches)
Title: The panorama of science and art
Year: 1823 (1820s)
Authors: Smith, James, 1759-1828?
Subjects: Technology Technology
Publisher: London : Caxton Press
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
, and the number of degrees or extent of the arc interceptedbetween the commencement and termination of its range, shewsthe intensity of the charge to which it is exposed. This in-strument is made as free from corners or sharp edges as pos-sible : the pillar and index are round and smooth, and the edgesof the semi-circle well rounded ; and as it is composed of im-perfect conductors, it is not apt to dissipate the electricity ofthe jar or prime conductor to which it is applied ; but if, upontrial in the dark, it is found to collect the electric matter, itmay be suspected to be damp, and should be brought withinthe warmth of a fire. The semi-circle cannot be too dry, butthe pillar may be rendered so dry as not to receive the electricfluid readily enough to have a proper influence on the index ;this defect, however, may be remedied by damping it. Theindex of the electrometer never rises higher than 90 degrees,because the repulsion of the stem, when it is at 90 degrees, is EiLlEiCTlRICITX
Text Appearing After Image:
nihlislicit Ill lUnri/ /i./irr. lUxlon. L.n.I.;,. ELECTRICITY. 219 To secure the feet of tlie insulating stool.—Experiments. equal on both sides of it; in charging a large battery, it willseldom rise so high as 90 degrees ; and when it rises above80, the charge may be considered strong. Insulating Stool. The insulating stool, represented at fig. 1, pi. II, is merely amahogany board with glass feet, which are varnished like otherinsulating supports that are made of glass. B) standing uponthis stool, the human body may be insulated ; and when, formedical purposes, it is necessary for a person to be insulatedfor a considerable time, it should be large enough to admit ofa chair to be set upon it. The usual fault of insulating stoolsis, that the feet are imperfectly fastened, and apt to come out.This may be prevented, if the feet be first cemented into brasssockets of at least an inch and a half deep, and these socketsscrewed to the wood ; but if the glass feet be let into thewood, they

Note About Images