The Greek portable sundial from Memphis rediscovered

Abstract

Experts studying antique astronomic instruments are well aware of a small class of so-called portable sundials from the Roman Empire. Over the past few decades, they have been considered in several important publications, including a recent book by Richard J. A. Talbert, in which he systematized the available information. Talbert and earlier J. V. Field described eight portable sundials of a “geographical” type, dating from about 2nd–4th centuries. Five are inscribed in Greek, the other three in Latin. The list of Greek dials also contains a dial from Memphis, information about which has been very scarce so far. Some authors even considered it lost. Fortunately, this instrument is stored in the collection of the State Hermitage Museum (St. Petersburg) and now we have an opportunity to study it more closely.