Description

This excellent apparatus greatly simplifies the
study of Coulomb’s Law. It consists of a rigid
fiberboard housing with a hinged glass-front
window mounted on a rugged wooden base. The
base has a groove to guide the wooden block in
and out of the housing. The bottom of the housing
contains a grid, and an adjustable mirror and ruler
are mounted on the back wall. The apparatus is
supplied with both a masonite and a lucite top,
a guide block, acetate and vinyl strips, graphitecoated
spheres, cotton and wool cloth squares,
monofilament, and polyethylene insulators.