That curious curiosty : The scotoscope

J. A. Bennett has extensively surveyed the instruments and apparatus associated with the work of the prolific 17th-century natural philosopher, Robert Hooke (1)*. In his account Bennett notes that Hooke’s microscopical researches and associated apparatus are so well known as to call for little further comment. There is perhaps one justifiable exception to this observation, namely the microscope lamp described and illustrated by Hooke in the Micrographia (2). It appears likely that this lamp, described by Hooke as ‘ much beyond any hitherto made use of by any I know ’, is identical with the somewhat obscure 17th-century optical device known as a scotoscope. If this is the case then the identification provides the solution to a minor lexicographical problem, and helps interpret some otherwise obscure microscopical observations that form the subject of an entry in Samuel Pepys’s diary.