Charlemagne's Clock

I never knew he had one. This is quite interesting. (From Daniel Mitsui.)

Gifford, in his History of France, thus describes Charlemagne's clock: But what particularly attracted the attention of the curious, was a clock worked by water. The dial was composed of twelve small doors, which represented the division of the hours; each door opened at the hour it was intended to represent, and out of it came the same number of little balls, which fell one by one, at equal distances of time, on a brass drum. It might be told by the eye what hour it was by the number of doors that were open; and by the ear, by the number of balls that fell. When it was twelve o'clock, twelve horsemen in miniature issued forth at the same time, and marching round the dial, shut all the doors. (Read entire post.)