English: Astronomical clock of de Dondi, showing gearing on the dial for Mercury and escapement crown wheel. The clock had seven faces, each of which was fitted with a dial. From Price,D.J.de Solla On the origin of clockwork, perpetual motion devices, and the compass
Uploaded a work by Price, Derek J. de Solla (Derek John de Solla), 1922-1983 from https://archive.org/details/ontheoriginofclo30001gut with UploadWizard
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