Consisting of a wounded coil 75 mm dia carrying 5 amp two
steel knife edges to support ball ended magnets, horizontal
scale 90 mm long, vertical scale 140 mm long and two terminals,
all on wooden base 360 x 100 mm fitted with levelling screws.
Balancing magnet has adjustable mass attach to alter sensitivity
of system, sliding cradle on vertical scale for second ball
ended magnet with 2 riders, 51 and 10.2 mg.