ELECTROSCOPE

an instrument for small charges of electricity. It ateachad of a stout fo on wire end, with enclose two In gold from which it is insulated. en is brought near the instrument, leaves become charged with the kind of electricity and repel each The electroscope can also be determine whether the charge is or negative. In some instruonly one leaf is used, the wire it. taking the place of the other leaf. electroscope has recently been large in the study of radio-activity,