Six bar magnets within a large, fitted wooden box. There are two 2-foot bar magnets with mirrors, one 2-foot bar magnet without mirror, one 1-foot bar magnet without mirror, two 9-inch magnets in a smaller fitted wooden box with keepers (by W. Simms). The bearing, part of a magnetometer, could be used with one of the 2-foot magnets. It is the original agate bearing for the first vertical force magnetometer at the Royal Observatory, Greenwich.

The magnets are recorded as having been used with the Meyerstein and Ernie magnetometers. The two smaller magnets are inscribed "W. SIMMS 585" and "W. SIMMS 589". The bearing is inscribed "Robinson London.