So the pendulum's job is to keep the torpedo level. The torpedo's depth is controlled by a diaphragm and compressed spring, which senses the pressure of the water outside the torpedo and adjusts ...

and the spring has to begin its work again. The balance wheel at each vibration allows one tooth of the adjoining wheel to pass, as the pendulum docs in a clock ; and the record of the beats is ...

Warm days ahead ...

You might recall the classical experiment in Freshman physics of two pendulums that are coupled together wtih a soft spring. This pendulum system is another example of a system that exhibits beating ...