CLOCK-WORK ROME - Sun dials & Clocks in the City

written by Sergio Caggìa with Michelle von Buren for © Nerone the Insider's Guide to Rome

 

New Year's Eve: I am sure that many of you counted down to midnight and the new year. This would have been very unusual if you had lived in a different era, not just because of the difficulty of counting the seconds with an hourglass, but also because the hours of the night weren't counted! Indeed, the counting of the hours started at dawn with the help of sun-dials which then indicated midday with sufficient accuracy for the needs of the time. The beginning of the day changed from dawn to the middle of the night with the invention of mechanical clocks which became ever more independent from natural phenomena as man's knowledge increased. It was necessary to adjust them frequently and sun-dials were the best reference. It may seem incredible, but sun-dials are still more accurate than the best watch you can buy, at least on determining midday in any chosen place regardless of the time zone. The desire to determine Easter Day with accuracy led the Popes to encourage scientist in elaborate methods and instruments. The problem was considered solved when the calendar was reformed under Pope Gregory XIII (1582) but it took over 150 years for this calendar to be accepted by all "civilized" countries, the last being ultra-conservative Great Britain in 1752.   There was great anxiety to test the accuracy of Gregory's calendar in Rome itself, and so the great sun-dial in the church of Santa Maria degli Angeli (Piazza della Repubblica) was built in 1702. This sun-dial is one of the most beautiful ones that Christianity produced, remarkable both for its artistic and scientific value. Stunning are the signs of the Zodiac in marble and brass placed along the line representing the meridian (unfortunately some of the brass stars were lost due to badly executed restoration a long time ago). Go and see it at midday* in the Church where, indifferent to the chaos into which modern Rome has fallen, this rite repeats itself silently every day. * Midday in Rome, and more exactly, in the Basilica, happens around 12:17pm. This is because the meridian chosen for the time zone in which Italy belongs doesn't correspond to the one passing through Rome. At this time of the year (January) the point of the sun-dial where the sun-ray crosses the brass line is near the sign of Aquarius (northen end of the line). More information about the sun-dial is on sale inside the sacrestia.    At the southern end of the sun-dial, you'll find a commemorative stone which translated reads: "This sun-dial, built in 1702 by Francesco Bianchini, indicated midday to the Romans until 1846 when the cannon of Gianicolo began to boom". As you can see, the statement contains a mistaken concept: the cannon is not an instrument for measuring time and needs someone to tell it when it's mid-day! The signal for the cannon to be fired was given by a black wicker ball dropped from the top nf the Church of St. Ignazio! The cannon was not fired from Gianicolo at the beginning, but from Castel Sant'Angelo where it gave the signal for all the churches of Rome to ring their bells. In 1903, the cannon was fired from Monte Mario and finally, in 1904, from Gianicolo. These signals also served to regulate the first mechanical clocks and probably two water-clocks to be found in Rome: one (which unfortunately doesn't work anymore) is in the courtyard of Via del Gesu 62, and the other in Villa Borghese (Pincio) see the map on page 2. This last was constructed by Giambattista Embriaco (frate Domenicano) in 1867 and is still working! Go and enjoy it and, by the way, take a look at the fountain of Moses nearby, where baby Moses is found by the Pharaoh's daughter in his whicker basket. Today, if you find yourself walking at midday in Trastevere or Campo de' Fiori you can still hear the cannon booming a moment full of history and romanticism and perhaps...adjust your watch!    MORE ABOUT THE SUN-DIAL In a commemorative stone placed in the wall in the presbytery of the Basilica of S.M.degli Angeli (on your left as you look at the high altar) you can see the ruler used by Francesco Bianchini for his mesurements. With it, he was able to determe midday to within two seconds! The stone also shows the results of his observations on the Equinox. It is possible to read in Roman numbers the day and time of this phenomenon. On a marble stone in the floor near the confessional box at the southern end of the brass line, you'll find the inscription: "FELIX TEMPORUM REPARATIO" and around "IaCobVs III D.g. Magnae brItannIae etC reX". This plaque is dedicated to James III of England who lived in Rome (from 1717) in exile and was recognised as King of England by the Pope. Adding up the capital letters reveals the year in which the King recognised the validity of the Gregorian Calendar (1721)...31 years before Great Britain officially did!