An electroscope isf used for detecting electric charge. A gold leaf is hung against a metal plate and if the plate is charged the leaf will be deflected away from it. In the presence of ionising radiation the charge will leak away and the leaf will fall. In this instrument the electroscope is connected to a pair of plates in the attached chamber, and it would have been used to monitor ionisation in this volume. There is a mounting for a microscope to observe the leaf, but the microscope is missing.
The engraving of the inscriptions is of particular quality.
Inscriptions / Translations: On base of chamber: Societe Centrale de Produits Chimique
Artist: Societe Centrale de Produits Chimique
ID Number: BIRRC-P0247
Institution: Research and Cultural Collections
Named Collection: Collection of Historic Physics Instruments
Object Type: Electrical instrument
Place Made: Paris
Materials: Brass with glass windows, on heavy stand on wooden base
Measurements: 27 x 26 x 34 cm