Andrew Morrall
Professor, Bard Graduate Center

“Turning Back the Sun: A Sixteenth-Century Sundial and the Miracle of Ahaz”

In a letter of 1572 to August I, Duke of Saxony, the Augsburg instrument maker, Christoph Schissler (C.1531–1608), presented an overview of his creations in the hope of receiving orders. Included among the terrestial and astronomical globes, astrolabes, planispheres, “unusual and wonderful” clocks, sundials, and compasses, was a “Horologium Ahaz Hydrographicum,” a sundial in the form of a drinking vessel, which, he claimed, could make time move backwards. It was based upon the miracle of the Dial of Ahaz as recounted in 2 Kings, 20:11, according to which God caused the shadows to retreat a full ten hours backwards in time as a sign to King Hezekiah that he would be brought back from the brink of death.

Focussing on a version of Schissler’s dial that exists today in the collection of the American Philosophical Society of Philadelphia, this talk will analyse the technical means by which Schissler recreated the biblical miracle, the design and narrative strategies employed, and the instrument’s status and intended function within prevailing conditions of patronage and against the horizon of his training and professional trajectory. By establishing the intellectual contexts of the instrument’s reception and afterlives, it is possible to suggest how the “Horologium Ahaz,” as a working model of solar recession, was used to support different sides in the urgent contemporary debates over questions of theology, natural philosophy, and astronomy.

Tuesday, October 20, 12:15 pm