ESHS/HSS Annual Meeting

Test Objects in Victorian Microscopy: Unexpected Uses and Users

• In Event: Scientific Instruments

English Abstract

This paper reassesses the use of microscopical test objects in Britain during a crucial period of optical development. The physician CR Goring and optician Andrew Pritchard borrowed the concept of test objects from astronomy in 1830. Typical natural test objects included diatoms and insect scales; soon, human-made test plates were marketed. These minute, intricately-patterned objects were challenging to see clearly, so working microscopists used them to evaluate the optical performance of their objectives. (Opticians also used other, non-intricate tests to check for defects when making lenses). Victorian microscopists described test objects as a key component of the nineteenth-century drive to calibrate instruments and coordinate expert observations, enabling the work of collective empiricism.

But test objects served in other ways that scholars have not fully appreciated. New technologies often get put to new and unanticipated uses and reach unexpected users. So, while ostensibly developed for advanced work requiring careful calibration, test objects were often used to train new observers. Unlike astronomical test objects, microscopical test objects became popular objects as well. They offered a striking and beautiful display of microscopical power to lay viewers in social settings, whether at intimate soirées or lively public screenings. Finally, these objects sparked debate over the best methods of training, the limits of light microscopy, the merits of various optical technologies, and the difficulty of the objects themselves. In short, microscopical test objects functioned differently in different contexts. They did support investigators’ efforts to standardize scientific practice, but they also attracted and trained novices, circulated broadly in popular culture as representations of microscopical work, and triggered contentious debates amongst the most elite microscopists about the very basics of their practice.

Author

• Meegan Kennedy, Florida State University