This image is released under a CC BY-NC-SA 4.0
Licence
Buy this image as a print
BuyLicense this image for commercial use at Science and Society Picture Library
LicenseHelmholtz's quadrant electrometer
Science Museum Group
© The Board of Trustees of the Science Museum
Helmholtz's quadrant electrometer, brass with lining of ebonite and tin foil, made by T.R. Voss, Berlin, 1876. Helmholtz improved Kelvin's quadrant electrometer by using Leyden jars made of ebonite or vulcanite rather than glass, which held charge much longer (14 days rather than 1). Needle and mirror could also be easily removed, and needle could be raised or lowered without shaking the instrument. See note.
