Ithaca Perpetual Calendar Clock with Pomeroy Movement

Here’s a neat old double dial (perpetual) calendar clock made in the early 1870s.

The calendar dial shows the day of the month around the outside, the day of the week in the left opening, and the month in the right opening. It shows the correct number of days in each month, even doing 28 days for February in regular years, and 29 days every four years for leap year.

Perpetual calendar clocks were popular in the United States from the 1860s to around 1900.

The rule for leap years is: if the year is divisible by 4, it is a leap year; but if it is divisible by 100 it isn’t a leap year, but if  it is divisible by 400 it is a leap year. Thus, the years 2004, 2008, 2012, 2016 and 2020 are leap years. The years 1700, 1800 and 1900 were not leap years. 2000 was a leap year but 2100 won’t be a leap year.

All of these perpetual calendar clocks showed February 29th on March 1, 1900 because they do a leap year every four years, but 1900 wasn’t a leap year.

See more pictures.

The calendar dial is labeled:

April 18th, 1865, and August  28th, 1866.

 The upper movement (time and strike) is labeled:

N. Pomeroy, Bristol CT, Patented July 13, 1869

Noah Pomeroy made movements and sold many to other companies that cased them.

The walnut case is 22 1/4 inches tall and 11 7/8 inches wide. The time dial’s minute track is 5 1/4 inches in diameter.

Repair job 6582. I polished the pivots, installed 11 bushings, replaced the broken strike mainspring, and adjusted the escapement (closed the pallets to equalize the drops).

Time mainspring: It is the original spring labeled W. Barnes; 3/4 inches wide by .017 inches thick.

Strike mainspring: It was broken and not original; I installed a new 3/4 by .0162 by 120 inch spring, Timesavers number 15959.

Note to calendar clock owners: don’t oil the calendar mechanism parts or try to adjust them. The only adjustment needed is how high the time movement lifts the calendar lever. The calendar movement should never wear out or get out of adjustment under normal use.


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  1. Hi… a family friend has this exact clock. It runs well, but the date is way off. Is there a resource available that explains how to set the date to the current date? Thanks!

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