Historical perspectives. Towards a definitive history of optical spectroscopy. Part II. Introduction of slits and collimator lens. Spectroscopes available before and just after Kirchoff and Bunsen's studies
Abstract
Careful reading of the original literature shows that it was Newton, not Wollaston, who first used slits in a spectroscope and Simms, not Meyerstein, who introduced the collimator lens. Good spectroscopes had been used by Simms, Masson. Swan and Meyerstein prior to the studies of Kirchoff and Bunsen who were not aware of this. The discussion of early spectroscope design concludes with Littrow's reflecting system.