Galileo, glassware, and the peacock

Abstract

This essay examines Galileo’s peculiar comparison of small lunar craters in 1610 in his first treatise of telescopic observations, the Sidereus Nuncius, to the eyes in a peacock’s feathers and to a particular sort of glassware, and it argues that these allusions reveal more about a certain kind of sound than about the visual appearance of the moon. Galileo’s odd analogies find subsequent development in a thought experiment relating sight, sound, and sensation in his Two New Sciences of 1638.