Clocks Around Rome, Part II


A few more clocks to show!

Up in the Pincian Gardens, where all the Math Guys are, is a water clock created back in 1867.  It only worked for about 40 years, however, and then was in disrepair for about a century.  Fortunately, only three years ago the clock was restored and now it totally works. Yay!  Here’s what it looked like when we were approaching it:

And here’s what it looked like when we were standing in front of it:

(Many of the clocks in Rome used Roman numerals, heh heh.)

Here’s a close up of the water portion:

The water pours first on one side, then the other.

Finally, here’s a close up of the plaque, which tells a little about it, if you read Italian:

And a 2007 article here by Brian Barrow which tells even more, including:

The timepiece is the result of the work of two men: Father Giovan Battista Embriaco, a Dominican priest and scientist (1829-1903), and the Swiss-Italian architect Gioacchino Ersoch (1815-1902). Apart from teaching physics and mathematics, Embriaco had the hobby of constructing mechanical water clocks (see box) in which the continuous emptying and filling of containers at the ends of a balanced arm produced the rocking motion which took the place of the traditional pendulum by moving a notched wheel at regular intervals.


Despite seeing quite a few neat clocks in Rome, we missed the six-hour clocks.  We’d found information about these on a site of Curious and Unusual things in Rome [a fabulous resource!], where it said:

When clocks finally began to appear on important churches and public buildings, some of them had a dial with only six hours, not twelve as in ordinary clocks, so to divide the day into canonical hours, when the prescribed prayers were to be recited. The bells, instead, rung up to twelve times, despite the dial, and the hours were counted up to 24! For instance, at the 21st hour (i.e. around 4 pm in summer) the dial would have shown III, and nine tolls of the bell would have been heard.

Only two of these dials are still extant, in the main cloister of Santo Spirito in Sassia complex, near the Vatican, and on the façade of Santa Maria dell’Orto’s church, in Trastevere district (pictures on the right).

We did sneak over the Santo Spirito, but couldn’t find the clock and there was a wedding just getting out (all the cars had big bows on the antenna; we saw this in another wedding procession the next day) so we didn’t really want to stand and look around.  I’m still not sure where it is.

BUT, as a bonus, we did unexpectedly run across two more sundials in the museum in Ephesus.


Ephesus was a Greek city before it became a Roman city before it became a Turkish city, which probably explains the Greek.  (Although it’s interesting that it’s letters instead of numbers.  Unless the letters are also numbers?  And if not, aren’t some letters missing?  I’m so confused.  Most of the stuff in the courtyard was unlabeled, so I couldn’t find out anything additional.)

Next up, even more math in Rome!  Unless I don’t get to it before Friday’s Carnival of Mathematics, in which case the Carnival will be the next up.

3 Responses to “Clocks Around Rome, Part II”

  1. Jonathan Says:

    The Eastern (Roman) empire was Greek, so anything else would have come as a suprise. I’m guessing (but don’t know) that the letters were the contemporary alphabet. Nothing, including Greek, is immutable. (Homer’s sheep, I’ve heard, said “veh, veh” if you read the old letters with modern sound values)

  2. Francisco Says:

    This is the alphabetic numberig typical from ancient greek and the bizantin period. From left to right you have: alfa = 1, beta= 2, … the sixth is a non common letter used specifically for numbers (stigma) and then it continues with the order of alfabetic letters with Dseta=7, Eta = 8, zeta=9, and then for 10 they used iota, and for eleven and twelve (iota plus alfa; iota plus beta).
    I like very much the picture. Could I used it to publish an article?

  3. simonsterg Says:

    Yes, see for more on the number system

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