Gridiron pendulum
From Academic Kids
The gridiron pendulum was an improvement of clocks developed by John Harrison, consisting of alternating brass and steel rods assembled so that the different expansion and contraction rates cancelled each other out.
Any downward expansion of the suspended steel is counteracted by the upward expansion of the supporting brass. The adjustable pin connection was designed to make minute alterations to the length, in the field.sl:kompenzacijsko nihalo
