Inertial movement detector ("Wobble meter")

Studies on belltowers with swinging bells are aided by measurement of tower lateral movement due to the bells' swing. The instrument shown in the photo was designed by Hervey Bagot and made in Adelaide to his specification. It has been used in studies of three Adelaide change-ringing belltowers. The body of the instrument is 250 mm long. It works on the principle of the seismometer (horizontal pendulum).