33.5 x 21.5
Brass, glass and wood
CAT. 1878 : 439
Pilha sêcca (electroscopio de Bonenberger).
Dry battery (Bohnenberger electroscope).
The Bohnenberger electroscope comprises two batteries connected by a common base. The free terminals have two small brass spheres. The unit is mounted in such a way that these two spheres have symmetrical electric charges.
A piece of gold leaf suspended on the stem of the electroscope is attracted by the sphere of one of the batteries when an electrically charged body is brought close to the electroscope. It is thus possible, with this electroscope, to determine the nature of the charge of an electrically charged body. To do so, the charges on the spheres should first be known; this can be ascertained by observing the behaviour of the gold leaf when the electroscope is influenced by a body whose electrical charge is known.
This electroscope was acquired by the Gabinete de Física in 1863.
Jamin, J.C., Cours de Physique de l'École Polytechnique, Paris, 1869, p. 40.