CLOCKING THE FOURS

However, artefacts in Wells Cathedral in Somerset, England indicate that neither is correct as an explanation of the origins of this usage. And that clockfaces simply represent the normal rules of writing Roman numerals when they were first drawn in the 14th century.

The oldest surviving clock-face in its original condition is on the clock inside Wells Cathedral in Somerset. It dates from before 1392 and the original mechanism – now in the Science Museum – has some claim to be the oldest surviving clock works in the world. The current mechanism that drives it is Victorian, but the face has not been changed for more than 600 years.

The innermost circle shows the age of the Moon – and uses Arabic numerals from 1 to 30. The next ring shows the minutes and uses Arabic numerals in groups of five 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 with 60 at the top. The intermediate minutes are shown by vertical stroke like a I.

The outermost circle is more than six feet (1.93m) in diameter and around it, in Roman numerals, are the twenty four hours of the day – noon is at the top indicated by a red star with the Roman numerals in gothic script I II III IIII V VI VII VIII IX X IX [this numeral has at some point apparently been fixed upside down] down the right hand side. Midnight is indicated by another red star at the bottom with I II III IIII V VI VII VIII IX X XI up the left hand side. Though it has to be said that the IX is not very clearly drawn, looking confusingly like a II.

But here we have the essential elements of the clock-face which have come down to us over 600 years – roman numerals for the hours with the 4 indicated by IIII; minutes and days depicted by Arabic numerals.

Clearly there is much less power here in the symmetrical balance argument – the dial is not symmetrical anyway. The Arabic numerals do not balance and the two or three stars in each sector of the clock-face are certainly not arranged to match those in the sector opposite. So why is IIII used instead of IV?

The answer I believe is found in manuscripts in the Wells Cathedral library. They show that the use of IIII – or more precisely iiii or iiij – for 4 was commonplace even though 9 was normally depicted by IX or ix. In other words, the subtractive principle was used for one but not the other.

· A Chronicle of the early 12th Century – certainly before 1135 – shows the line of English Kings not with their dates but with the length of their reigns. Here are three from the list

Adelardus xiiii

Edouardus fili xxiiii

Aylredus ix anni et vi ebdomadibus (9 years and 6 weeks)

· A hundred odd years later, in the mid 1200s, a copy of the Liber Ethinmologiarum by St. Isidore of Seville (died 636) was written out. Liber V (Book 5) lists the contents of the section Of the Lawgivers – of Divine and Human Laws. The verso of folio 36 lists 39 headings. It uses iiii exclusively for 4, but ix exclusively for 9.

· Pages from a 15th century service book also survive in the library. One page has notes in red ink above the text giving numbers. Again, it uses iiij exclusively for numbers ending in ‘4’ and ix for those ending in ‘9’. Two examples - lxxxiiij for 84 and lxix for 59.

So the clock-faces we see today could be the last surviving remnants of the style used by the mediaeval scribes when writing Roman numerals.

Exceptions
The practice of using IIII rather than IV on clock-faces, although common, is not universal.

The well-known clock, commonly called Big Ben, at the Palace of Westminster in London, where Parliament meets, has gothic style Roman numerals round its face and the 4 is depicted as iv. It dates from the 1850s. Strictly speaking, the hour bell is Big Ben, the clock is the Great Clock, and the tower is the Clock Tower. The building is correctly called the Palace of Westminster but most people refer to it as the Houses of Parliament.