Horolovar 400 Day Clock Repair Guide 10th Edition Revised and Updated written by Charles Terwilliger and edited by H.W. Ellison This book thoroughly documents the history of the 400-day clock. It also contains guidelines on repairs, adjustments, pendulums, and other components. It includes extensive collection of back plate and suspension illustrations which aid clock identification and the selection of replacement parts. Hard Cover, 237 Pages.