Microbalance, c1950s, used for weighing crystals for diamagnetic susceptibility prior to commercial Cahn balances. It was made at UCL as a copy of one from the Royal Institution, made by J Robertson who worked with Bragg. Housed in a wooden case, the microbalance comprises two wound coils through which current is passed, tiny pans to weigh crystals and a magnetised needle to show weight after calibration.

From a collection relating to the X-ray crystallography research carried out by Dame Kathleen Lonsdale at University College London.