What is a Perpetual Calendar? A perpetual calendar is a calendar mechanism which, unlike a simple calendar, automatically adjusts to the correct day of the month by accounting for the varying durations of each month, as well as self-correcting for the 29th of February during leap years. Audemars Piguet are said to have been the first to produce wristwatches with perpetual calendar and moon phases, in 1924. In 1925, Patek Philippe modified a lady?s pendant watch with perpetual calendar to produce the world?s first instantaneous changing perpetual calendar wristwatch with leap year indication.
What is a Minute Repeater? A minute repeating watch tells the time both visually and audibly. A slide on the side of the case, usually near the 9, will activate two hammers in the movement. These hammers strike two gongs curled within the case. First one hammer strikes a gong of lower tonality; it will count out the hours. Then both hammers will strike both gongs alternatively to count out the quarter hours after that hour, and then the second hammer alone striking a gong of higher tonality will count out the minutes after that quarter hour. The repeating mechanism was developed by Daniel Quare. In 1687, he had patented a mechanism that sounded the hours and the quarter hours. The early repeaters used bells. At the end of the 18th century, two bent-wire gongs became the more popular mechanism. In 1892, the first minute repeater wristwatch was produced by Omega, a model with a round-shaped case.