Calendar Clocks
Calendar indicators have appeared on clocks since the late 17th century. Some clocks displayed the days of the month on the outside edge of their dials, while clocks that were large enough for two dials used one to show the time and another to mark the day of a particular month. The most complicated vintage calendar clocks also indicated moon phases, high and low tides, the days of the week, and the year, with the best clocks even correcting for leap years.
In colonial America, calendar dials were featured on roughly half of the grandfather or tall-case clocks made at that time, often as a date appearing in a simple circular opening or curving lozenge-like aperture cut into the dial. Most eight-day clocks of this period also featured day-of-the-month indicators. But as clockmakers moved away from grandfather clocks to more portable and economical mantel clocks, calendars became less common to colonial-era clocks.
That trend began to reverse in 1853, when John Hawes of Ithaca, New York, was granted the first calendar-clock patent. Though his design did not correct for leap years and was never put into production, Hawes’ patent apparently spurred others to secure calendar-clock patents of their own. Within a year, William Akins and Joseph Burritt, also of Ithaca, received a patent for their calendar-clock mechanism, and some time after 1857, they sold their patent, along with an improvement, to yet another pair of Ithaca entrepreneurs, who hired James and Eugene Mix to actually build it. The Mix brothers received two more patents, further improving upon Akins' and Joseph Burritt’s original design, and in 1863, all of this intellectual and physical property was sold to the Seth Thomas Clock Company of Connecticut. Seth Thomas would make calendar clocks using this particular calendar mechanism until 1876. During the intervening years, Seth Thomas’ double-dial wall clocks were steady sellers, among them the “Peanut,” which was so named because its rosewood-veneer case came to points above the clock dial and below the calendar dial.
If double-dial clocks seem elaborate, consider the clocks that had three dials—one to tell the time, one to display the day of the month, and a third to function as, for example, a barometer. Such clocks were not uncommon at the end of the 19th century, when small pendulum, mantel clocks were produced by English companies in India using French clock parts.
In addition to Seth Thomas and the Ithaca Calendar Clock Company, which patented a mechanism to accurately account for leap years, resulting in what became known as the perpetual clock, clockmakers that made calendar clocks include Welch, Spring and Company of Connecticut, whose calendar mechanism was supplied by Daniel Gale. Welch, Spring and Company also produced Gale’s Astronomical Calendar gallery clock in 12- or 24-inch dials. Packed into these single dials, regardless of their size, were a minute and hour hand, indicators for the day, week, and month of a year, a table that calculated sunrises and sunsets, a section for phases of the moon, and a small hand to help users keep track of the number of years since the last leap year. Also in Connecticut was clockmaker E. Ingraham & Co., which made an Ionic Calendar wall clock that featured a pair of dials like those made by Seth Thomas. Meanwhile, in and around Boston, Aaron and Simon Willard made tall-case clocks with indicators for days of the month and phases of the moon.
Source: https://www.collectorsweekly.com/clocks/calendar