Mechanically adjustable balance and sensitive tilt meter

A torsion balance has been modified by clamping the fibre, under tension, at both the top and the bottom of the instrument housing. Operating with the centre of mass of the boom displaced from the near vertical fibre, the instrument is influenced by the Earth's gravitational field as well as by the shear modulus of the fibre. This causes the restoring constant of the balance to depend on the angle of tilt between the fibre direction and local vertical. The contribution from the Earth's field either adds to or subtracts from that of the shear modulus, according to the direction of tilt. The result is an instrument of variable sensitivity when used as a force-measuring device. It can also be configured to function as a highly sensitive tilt meter.