The mechanical anniversary clock, also known as the 400-day clock or torsion pendulum clock, is one of the most popular clocks ever invented. Anniversary clocks are recognizable by the decorative balls beneath the dial that rotate one way and then the other.
- Limba : Engleza
- Data Publicarii : 27 May 2009
- Format : Paperback
- Numar pagini : 48
- ISBN : 9780747807339