Bauhaus-Universität Weimar

Titel:
Optical Projection: A Treatise of the Use of the Lantern in Exhibition and Scientific Demonstration
Person:
Wright, Lewis
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit39439/358/
MAGNETISM AND ELECTRICITY 
397 
Quantitative measurement is more difficult, but Prof. 
Mayer has lately used a pendulum electroscope in a form that 
makes a most sensitive electro¬ 
meter. He suspends a gilt 
pith-ball 1 cm. radius (built up 
of small pieces cemented) a 
distance of 364 cm. from the 
ceiling, by two silk fibres 
fastened 52 cm. apart and 
meeting at the ball, behind 
which a scale is arranged. A 
brass ball of the same size is 
mounted on a glass rod, var¬ 
nished while warm with 
paraffin wax. A force of only 
one dyne acting on the sus¬ 
pended ball deflects it 13*3 
mm. ; and charging both balls 
in contact so as to give the 
same charge to each, the 
charge c on either was found 
in absolute electrostatic units 
by the formula 
C = D 
where d is the distance in 
cm. between the centres of 
the balls, and cl the deflection 
from the vertical in cm. 
When d is over 5j cm. the 
law of inverse squares was 
demonstrated within 1 per 
cent ; and by using a proof- 
plane, Coulomb’s law of distribution on the pay 
drical body was verified with close approxima/ioh> Shell 
LJ # /
        

Nutzerhinweis

Sehr geehrte Benutzer,

aufgrund der aktuellen Entwicklungen in der Webtechnologie, die im Goobi viewer verwendet wird, unterstützt die Software den von Ihnen verwendeten Browser nicht mehr.

Bitte benutzen Sie einen der folgenden Browser, um diese Seite korrekt darstellen zu können.

Vielen Dank für Ihr Verständnis.