‘Sundials and Other Cosmographical Instruments’: Historical Categories and Historians’ Categories in the Study of Mathematical Instruments and Disciplines

Abstract

In 1635, the Scots-born Jesuit Hugh Sempill published a twelve-book text on the mathematical disciplines. Sempill devoted book seven of this work to the subject of cosmography; subsequent books consider what he described as the constituent elemental and celestial parts of that discipline, namely geography (book eight), hydrography and meteorology (book nine), astronomy (book ten), and astrology and calendrics (books eleven and twelve). Chapter eleven of book ten is entitled ‘Of Sundials and Other Cosmographical Instruments’. This one chapter, easily overlooked amid the wealth of material regarding the mathematical disciplines in the early modern period, is of considerable interest to historians of science and curators of scientific instruments. At first sight, it constitutes an extraordinary vindication of the claim, advanced by former Whipple Museum Curator Jim Bennett, that sundials were cosmographical devices in the long sixteenth century. Bennett presents the Renaissance discipline of cosmography as a key to unlocking the true meaning of these objects, all too frequently understood merely as time-telling devices.