Maltese sundials

Abstract

Although Maltese craftsmen mastered the art of clock-making centuries ago, as evidenced by the reference to a Maltese Arab clockmaker of the first half of the twelfth century who had constructed a remarkable timepiece for the Qa'id of Malta (Vella, 1974, pp. 83- 84; Wettinger & Fsadni, 1983, p. 37; Wettinger, 1984), the practice of telling the time by means of the sun and the shadows it casts persisted over the ages up to our times. This practice started thousands of years ago as indicated by one of the inscriptions on the cenotaph of the Egyptian pharaoh Seti I (about 1300 BC) which shows a simple sundial and gives a description of its use (Neugebauer, 1969, p. 86). 1 But it is not known when this practice was first adopted in Malta. The earliest extant sundial in the Maltese Islands is probably the vertical dial adorning the south wall of an old building in Xewkija, Gozo which bears the date 10 April1546 and the caption ENCHOR (Figure 1). Although it is damaged and its gnomon (shadow marker) is missing, this elegant dial still exhibits 13 well-defined equally spaced lines radiating from its centre. The slanting lines mark each of the six hours before and after mid-day and the vertical line marks twelve noon. Its design is rather special but since the gnomon is missing, it is not possible to tell whether this sundial is in its original position or whether it is incorporated on a later wall simply as a decorative element. Many other designs exist, in fact sundials come in all forms and shapes. Most have a flat surface, others are slightly curved, and a few consist of a hollow bowl (Herbert, 1967). All have a gnomon which can either be vertical or horizontal but which is usually inclined with respect to the dial. Irrespective of its design, the purpose of the sundial is to capture the apparent regular motion of the sun and project it on a scale which can be used to divide the day into equal periods of time, usually hours. It follows that to understand how any sundial works, it is necessary to apply some simple knowledge of the apparent diurnal and annual motion of the sun. A brief description of this motion follows for easy reference. It is interesting to note that the Ptolemaic theory that the sun goes round the earth is perfectly acceptable for our purpose. In fact Ptolemy developed the mathematical theory of the sundial in the second century AD in his work On the analemma (Neugebauer, 1975, pp. 839- 856).