The gridiron pendulum was an improved clock pendulum invented by British clockmaker John Harrison around 1726, which didn't change in length with temperature, so that its period of swing stayed constant with changes in ambient temperature.
The gridiron pendulum was an improved clock pendulum. This improved clock pendulum was invented by British clockmaker John Harrison around 1726.1726 didn't change in length with temperature. Its period of swing stayed constant with changes in ambient temperature.