Maker's Name: 
14 × 7.5 × 5 cm

Used to determine the Young's Modulus of elasticity of a wire by the method of G.F.C. Searle described in Worsnop and Flint, Advanced Practical Physics for Students', p85, whereby the stretching of a wire hanging from the ceiling under increasing load is monitored by comparison with a second wire with a constant load. The extension is measured by a null method involving returning a bubble level to an original position.

This is the only survivor of six listed in the Equipment Register book. The micrometer screw is missing its dial.