Doppelmayr and the illustration of early modern physics.

During his long tenure at professor of mathematics in Nürnberg, Johann Gabriel Doppelmayr (1677-1750) translated the Astronomia Carolina of Thomas Streete into Latin, composed a book on sundials, wrote on spherical trigonometry, and rendered the sectors, calipers and scales of Nicolas Biot into German. He wast most famous for his celestial atlas, but also compiled an influential textbook on contemporary electrical theory, the Neu-entdeckte Phaenomena von bewunderns-würdigen Würckungen der Natur (1744). In this, he compiled the experiments of Hauksbee, Dufay, Pieter van Musschenbroek, and Willem ‘sGravesande into a single volume of accessible gebrochene Schrift, complete with folded engravings which have since become quite famous.

The image above depicts several of the experiments conducted by Stephen Gray (1666-1736), a dyer from Canterbury and amateur natural philosopher, who began the first sustained experiments in electrical conduction while living as an impoverished pensioner in Charterhouse in Smithfield, London. Doppelmayr extracted these primarily from Gray’s descriptions, which were published in Philosophical Transactions as a letter to Cromwell Mortimer (vol.37, 1731); in this, Gray used a cork-capped flint-glass tube and bit of eiderdown for his first experiment (fig.1), before moving on to suspend guineas, shillings, brick, tiles and chalk from the line; he then used flakes of leaf-brass and lengths of cane and silken thread to observe electrical conduction at significant lengths, and in various directions. After successfully charging a paper world-map, umbrella and soap-bubble, Gray attempted an experiment using a volunteer from Charterhouse, in sessions from 8-21 April 1730, by suspending him from the ceiling with clothesline, and placing leaf-brass on paper plates. The lower diagrams are from Gray’s collaborator, J. Desaguliers, and suggest a preliminary question. How does one visually depict force in an engraving, and capture the passage of time in the amber of a printed page?