Medieval town clocks

by Jubal Freeman

Now, let’s take a look at the kinds of clocks that the verge escapement was used in.

Most medieval clocks were town clocks, and many had astronomical faces.

This clock in Prague is a good example.

It was installed in 1410, and still runs today. Wikipedia has a decent overview of the clock, but this site is a bit better I think, even with some translation issues.

Here’s a good animation of how the dial works

You may notice that the dial is very different from clock faces today. That’s because the town clocks were for more then just telling the hour of the day. Astrology was widely accepted at the time, so the astronomical face was used to determine what days were good for various tasks, what sign of the zodiac a baby was born under, and whatever else they could manage to connect to the movements of stars and planets.

The big difference between mechanical clocks and water clocks, sundials, and hourglasses, was how they kept time, not accuracy. Mechanical clocks marked shift from telling time by the position of the sun, or a flow of water and sand, to time measurement based on a periodic event. We still tell time in basically the same way, the only difference is what event is used. Mechanical clocks use an escapement that ‘ticks’ at a uniform speed under a given amount of force, where quartz clocks work off of the vibration frequency of  quartz crystal, but both are doing the same thing.

This change to a method of timekeeping that was ‘external’ instead of based on the sun, or how long ago someone flipped the hourglass, did something, it started to change how people saw time.

Back then, and now in some places, time wasn’t as rigid as we see it now. Instead of ‘noon’ being within 60 seconds of 12 o’clock, it was when the sun was pretty much straight up, and that could give you a range of half an hour or more. One thing the more accurate clocks enabled was another way to figure out productivity. Instead of only being able to figure “I can make x widgets per day” it was possible to figure productivity per hour, and form that we now have jobs that pay by the hour, phone calls we pay for by the minute, and cooking times (in microwaves) measured in seconds.

There were many other changes that clocks had a hand in between the 1400’s and now, but a more detailed look will have to wait for another post.


Jubal Freeman