Inventory no. 78410 - Former Display Label
English IMPROVED GOLD-LEAF ELECTROSCOPE
c.1850
Unsigned
Gold leaves enclosed in a glass dome which fits into a groove in the mahogany base. Flat brass circular cap with point for small charges, with connecting rod enclosed in a varnished clear glass tube, and ending in a wedge to which are pasted two gold leaves. Two long strips of tin foil pasted to the inner surface of the dome are in contact with the tin foil pasted to the base.
The Reverend A. Bennet replaced Canton's pith-balls by two thin gold strips in 1787, thus greatly increasing the sensitivity of the electroscope. He probably was not the first to do so; Waitz in Germany had used thin metal strips in 1745. Bennet also pasted two tin foil strips to the inner surface of the glass dome, as H. de Saussure had done in 1785 in Geneva. When the excessively charged gold leaves touched these strips they would be earthed, which prevented the leaves from being damaged. G. J. Singer in 1814 improved the instrument further by insulating the brass connecting rod which connects the gold leaves to the cap by enclosing it in a resin filled and heavily varnished glass tube. H. de Saussaure is sometimes inaccurately cited as having made the same modification.
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