The wheels of time are 3, that is, 2 toothed and the third moves the time. Of these, the first wheel has 64 teeth and moves a pinion of 8 teeth. The second wheel has 48 teeth and moves a pinion of 6 teeth. The third wheel is the one that moves the time; it has 21 teeth. And the outer wheel that shows the hours has 96 teeth, and the pinion that moves it has 4 teeth.

p, 8, 48

This is keyed with 2 keys, that is, one near the centre, the other at the far end.

h 24, 6, 6 K, g q i 8, 36 l 2, 6 21 m 48 125, a, 8, p m, 48 r 8, f, 12, b c, 64 t 5, 4, e 48, 12 y, n X, Y

r is the wheel of the first motion. And in its turning, with its tooth it moves the sickle-shaped lever X aside, whereupon the lever Y rises and raises the instrument of the 3 keys b c a. And likewise it raises the support l, which is the last key. For when l rises, the tooth b descends and rests and stops upon itself until the tooth of the first motion has passed beyond the lever X. But before that tooth e has passed the lever X, the 3 keys a b c are already unlocked and set upon the lips of their notches. And the wheels would already run on their course were it not for the key q l, which makes them wait until the lever X has passed the tooth e of the first motion. And know that the wheel of the counterweight of the hours has 48 teeth, and it joins with its pinion of 8 teeth, and has 12 teeth with which it raises the hammer of the hours. The second wheel likewise has 48 teeth, and on its back has fixed the little wheel p, which with a single notch receives the key a, and turns above itself a pinion of 8 teeth. The third wheel has 36 teeth and on its arbor the tooth q, which is the last key; and above itself it has the pinion of 6 teeth. The fourth wheel has 24 teeth and moves a pinion of six teeth in place of a fly. And the wheel of the keys has 125 teeth.

Lever which sounds the hours by raising the hammer.

The pinion that moves the wheel where the end of the hours is keyed, with 125 teeth, has 5 teeth.