'A Scottish Clock Dial for Determining Easter'
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John A. Robey ‘A Scottish clock dial for determining Easter’ Antiquarian Horology, Volume 35, No. 2 (June 2014), pp. 827−833 The AHS (Antiquarian Horological Society) is a charity and learned society formed in 1953. It exists to encourage the study of all matters relating to the art and history of time measurement, to foster and disseminate original research, and to encourage the preservation of examples of the horological and allied arts. To achieve its aims the AHS holds meetings and publishes books as well as its quarterly peer-reviewed journal Antiquarian Horology. The journal, printed to the highest standards with many colour pages, contains a variety of articles, the society’s programme, news, letters and high-quality advertising (both trade and private). A complete collection of the journals is an invaluable store of horological information, the articles covering diverse subjects including many makers from the famous to obscure. The entire back catalogue of Antiquarian Horology, every single page published since 1953, is available on-line, fully searchable. It is accessible for AHS members only For more information visit www.ahsoc.org Volume 35 No. 2 (June 2014) has 144 pages. It contains the articles and notes listed below, as well the regular sections Horological News, Book Reviews, AHS News, Letters to the Editor and NUMBER TWO VOLUME THIRTY-FIVE JUNE 2014 Further Reading. Eduard C. Saluz, ‘The German Clock Museum in Furtwangen – 160 years of collecting’, pp. 769–782 Alice Arnold-Becker, ‘Friedberg – a centre of watch- and clockmaking in seventeenth and eighteenth century Bavaria – Part 2’, pp. 783–795 Françoise Collanges, ‘Jean-Eugène Robert-Houdin (1805–1871). From mechanical to electrical horology’, pp. 796–806 Thomas R. Wotruba, ‘The horological world of François Arsène Margaine’, pp. 807–826 John A. Robey, A Scottish clock dial for determining Easter’, pp. 827–833 Ian White, ‘Anatomy of a Cox musical clock’, pp. 834–837 1 JUNE 2014 A Scottish clock dial for determining Easter John A. Robey* A very unusual dial from a Scottish clock, probably added to a lantern clock to convert it into a longcase clock, has manually adjustable indicators that show the dominical letters and epacts. The use of these to determine the date of Easter is explained, and biographical details of the clockmaker and the dial’s first owner are given. Apart from a few Edinburgh lantern clocks, near the lower edge, this dial is virtually the thirty-hour clocks are said not to have been same as the one with a lantern clock made in Scotland, but here is a rare movement described by Spittler (n.1), and exception, made by Andrew Watson of St it is typical of a 30-hour country-made dial Andrews, Fife, the earliest clockmaker of the period, apart from the special features recorded in the town. The only other in the centre considered here. published record of a Scottish thirty-hour The rear of the dial (Fig. 2) shows the clock is a London lantern clock converted supporting rollers for the date ring, which is into a longcase clock by the same maker.1 A missing, and there are marks indicating its few other thirty-hour dials by Watson are location. The dial feet are widely spaced known, including another one similarly which might accommodate a large converted from a lantern clock, but no horizontal plate-frame movement, but a photographs are available.2 Of the clock few other clocks are known with a new dial described here only the dial survives, the fitted to a lantern movement using a large movement being missing. falseplate. The dial of the clock illustrated The 12in square dial is signed by the by Spittler fits directly onto the lantern clockmaker on the lower edge of the chapter clock movement, but the bell overhangs the ring (Fig. 1). The dial plate, which has been top of the dial, which has to sit back in the gilded, is also inscribed with the name of hood, resulting in a large gap between the the first owner along the bottom edge: dial and the door frame, there being no ‘David Peatie Wever [weaver] in Kings Barns mask. It is likely that Watson soon 1726’. Kingsbarns is a small village on the appreciated the problem and solved it by coast about six miles south of St Andrews. using a falseplate to bring the dial forward The dial is naïvely engraved, probably by of the movement. The spacing of the feet on Watson himself, with a matted centre, a the present dial indicates that it too had a ringed central hole for the hands and a very falseplate, almost certainly to fit a re-used small ringed calendar aperture. The corner lantern clock movement. (The label on the spandrels show twin cherubs holding a back of the dial is by a previous owner and crown, a pattern popular at this period. the information is not correct.) There are no winding holes, so the Above the centre is a silvered plaque movement was pull wound. The remains of engraved with the dominical letters A B C D small holes and rivets indicate that an arch E F G, also known as the Sunday letters, has been added at some time and while to the right of centre is a silvered ring subsequently removed. Apart from the engraved with the epact: 1.• 12 • 23 • 4 • 15 special subsidiary dials and the inscription • 26 • 7 • 18 • 29 • 11 • 22 • 3 • 14 • 25 • 6 • *John Robey ([email protected]) is a publisher of horological books and a clock restorer. He is the author of the extensively revised The Longcase Clock Reference Book (Mayfield Books, 2nd edition 2013). Current research topics range from early iron clocks and lantern clocks to the makers of painted longcase dials. 1. T. Spittler, ‘Converted Clock. An early Scottish 30-hour longcase with a lantern movement’, Clocks, August 2005, 14-18. 2. Information from Michel Dareau. 827 ANtiquarian HoRology Fig. 1. two-handed thirty-hour dial signed ‘Andrew Watson St andrews’. the matted centre has a ringed centre hole, small calendar aperture, a large round hole (possibly for adjustment of the date ring) and subsidiaries showing the dominical letter and epact. Note the naïvely engraved chapter ring and the name of the first owner on the lower edge: ‘David Peatie Wever [weaver] in Kings Barns 1726’. 17 • 28 • 9 • 20 (Fig. 3). The pointers of both Easter Sunday for a particular year the subsidiary dials are riveted at the back to dates on which Sundays and full moon small pieces of brass that act as friction occur are needed. The former is given by washers. These appear to be original, with the dominical letter, the latter by the epact. no signs that the pointers ever connected to the movement. It is suggested that they The Dominical Letter were intended to be adjusted manually The days of the year from 1 January to 31 every year as an aide-mémoire. December are denoted by a continuous The two subsidiary dials would have recurring cycle of seven dominical letters: been used in conjunction with a printed A, B, C, D, E, F, G. The letter A is set against table to find the date of Easter and the other 1 January, B against 2 January, C against 3 movable feasts, which are determined by January, and so on. The dominical letter of the phases of the moon. To find the date of a year is the letter of the cycle corresponding 828 JUNE 2014 Fig. 3. Detail of the epact dial. the Julian epact Fig. 2. Dial rear showing the rollers for the starts at 11 near the bottom. missing date ring and the friction ‘washers’ for the subsidiary indicators. Note the very wide 1 approximately 29 ⁄2 days) by 11 days. As a spacing of the dial feet (one missing). result, the age of the moon on corresponding days of successive years differs by 11. By to the day on which the first Sunday (and adding 11 days to the age of the moon on a thus every subsequent Sunday) falls. For certain day, the age of the moon on the leap years there are two dominical letters, same day of the subsequent year can be one for January and February, the other for found. The epacts for succeeding years are the rest of the year after the leap day. Since 12, 23, 34, and so on, but after the thirtieth the first and last days of the year fall on the day the numbers are regarded as being in same day of the week, the day for any date the next lunar month. After the epact of 29 advances by one day every year, and by two the next one is 11 rather than 10, followed days from March to December in a leap by 22, 3, 14, and so on. year. Hence the dominical letter decreases The epact of a particular year was by one every year and by two letters in a originally defined as the age of the moon in leap year. For example. in the Julian days on January 1 and while it can be used calendar which was still in use in Great to find the lunar date from the solar date it Britain when this clock was made, 1 January was primarily used in connection with 1726 was a Saturday, so the first Sunday tabular methods for determining the date of was 2 January and the dominical letter was Easter.3 B. For subsequent years it would be A for Calendars are only approximations to 1727, FG for 1728 (a leap year), E for 1729, represent the actual solar cycle in terms of and so on.