The pendulum works fine better than fine a good pendulum clock can keep time to within a few seconds a year but that's in a stationary clock and even back in 1680 when the ink was barely dry on Huygens' Horologium link Oscillatorium it ought to have been glaringly link obvious that putting a pendulum link in something that's going to get bounced around in a belt pouch this was before the advent of pockets isn't where the smart money was. link