[Dino]

OK this is a pretty basic drawing but it's as close as I could get to the original design. It's got lots of details missing, but you can see the basic concept and stylising. The pendulum rocks the balance bob, which turns the gears, and a seperate pendulum pumps water into the weight, which drains out through the bottom of the weight into the collection pan. This makes sure that the weight is light when it's down, and heavy when it's up. Also the mechanism has a kinetic limiter, which helps to even out the motion. The two balance bobs are linked, so that they move in sync, but the second balance bob has a pendulum to reduce kinetic energy loss.

EDIT: Oh yeah, and also the hands move in a circular trajectory around the face circumferance, rather than from the middle of the face. This simplifies the mechanism somewhat.