Christiaan Huygens’ first pendulum clock.

Using empirical testing Huygens devised the methods and features necessary to substantially improve the accuracy of the pendulum clock, realizing the optimal solution on Dec 25, 1656.

One of the critical features were curved metal plates near the pivot point that modified the swing of the pendulum from a regular arc to a cycloid.

“…at first, I suspended the pendulum between two curved plates …, which by experiment I learned …how to bend. And I remember having so well adjusted two clocks in this manner that in three days they never showed a difference of even seconds although in the meantime I often changed their weights rendering them heavier or lighter ” Credit Antique Horology.

Discover more:

Identification and attribution of Christiaan Huygens’ first pendulum clock