The 10th edition is the most recent of Charles Terwilliger long in print book on 400-day clocks. First printed in 1953, the has grown edition-after-edition thanks to the many aficionados of these fine clocks. For those not familiar with the book, it's most notable feature is a large section of movement back plate illustrations. Repairmen will enjoy the sections dedicated to parts, such as pendulums, ratchet wheels, and suspension brackets and saddles. These is also a section on names and trademarks found on dial faces and much more.
The Horolovar guide is rich in information. It has a history of the 400-day clock. There is a chapter on technical developments through patents as well as a discussion of the problem of temperature change and keeping time. A nine-page section showing some outstanding pre-World War I 400-Day clocks closes out the first part of the book.
The Horolovar 400 Day Clock Repair Guide is definitive and will not disappoint anyone with an interest in 400-day clocks.
