OUP (2017) h/b 236pp £35.99 (ISBN 9780190273484)

If you open this elegant volume, copiously illustrated with black and white photographs, charts, maps and tables, anticipating ‘a technical study’ aimed at ‘chronometric specialists’ (p.3), you will not be disappointed. T. begins this scholarly work with a general consideration of ancient concepts of time and familiar devices for recording it, such as clepsydrae and fixed stone sundials, before proceeding with a meticulously detailed catalogue of the 16 known bronze portable sundials from the Roman period in order of their original publication. Each entry records the sundial’s current location, material, dimensions, provenance, description, approximate dating and specialist bibliography, along with photographs or drawings and maps of the locations mentioned on it.

However the second half of the book offers another dimension to this study, aimed more at the interested general reader. The author proposes that these specialised objects are in fact unique ‘indicators of an educated public’s geographical awareness and worldviews’ (p. 111), demonstrating not just that the ancients generally conceived of time being regulated by the Julian calendar, but also of a world that was largely without maps as having a North/South orientation. The unanimous use of latitude by the sundial designers in their organisation of place names testifies to the widespread influence of Ptolemy’s Geography on the thinking of the era.

T. speculates on the designers, makers and purposes of portable sundials and on how their considered, rather than random, choice of locations leads to the conclusion that some at least were individually designed for a personal voyage or tour of duty or as a travel memento, and give the impression of confident special awareness and a wide-ranging worldview on the part of the compilers.

Their compactness, in spite of the considerable amount of data they display, and the sheer difficulty of using them to tell the time successfully also leads to hypotheses about the sorts of owners who would be attracted by such an ingenious piece of technology. T. suggests a link between them and the interest among the educated elite of the period in the collection and organisation of knowledge, apparent in contemporary technical treatises and encyclopaedias like those of Pliny the Elder, as well as the ability to move beyond memorised lists of literary place names instilled by the traditional Roman school curriculum with a confidence that was fostered by the relatively peaceful condition of a largely Roman world. These gadgets were basically invented to help their owners tell the time in the kind of society where travel had become easier and more widespread than before and where the main daytime activities were (even though imprecisely by modern standards) regulated by the passage of hours, a society which was more time-conscious than we might imagine, by testimony of Roman interests in astrology and horoscopes or records on tombstones of beloved children’s lives not just in years, months and days but sometimes even in hours.

The final chapter deals with the influence of portable sundials on later timekeeping devices, such as the astrolabe and navicula, extending to Nuremberg sundials of the 15th-17th centuries, Scottish stone sundials of the 17th-early 18th centuries, and even as far as the expensive wristwatches of today’s globetrotters and worldwide financiers with five time dials and instant adjustment for multiple time zones.

The book concludes with an appendix on the Aquincum fragment in Budapest, perhaps a portable manual for a sundial maker; a gazetteer of cities and regions with latitude figures and maps, a table of latitudes and locations, detailed bibliography and index.

Although displaying some lighter touches, such as the proposal of Trimalchio as the likeliest sort of person to own a geographical portable sundial (pp.169f.), this study remains primarily a book for scholarly specialists.

Claire Gruzelier