The motive power is supplied by weights (N, K) but the pace at which they fall and hence the time-keeping ability of the clock is regulated not by an escapement as in conventional clocks of the period but by a paddle (K) with a hole pierced through it (I). The weight causes the drum or tympanum (A) to rotate but the speed of that rotation is controlled by the rate at which the water (B) can move through the paddle. This is so arranged as to take a hour at the end of which the paddle breaks free of the water and the drum can rotate rapidly to operate the striking mechanism (S,T,V,X,Y) before resuming the timing of the next hour. Other mechanisms attached to the drum display the hours in the moving sun ( Fig. 19) and control the striking (Fig. 20). |