A general theory for the mensuration of the angle subtended by two objects, of which one is observed by rays after two reflections from plane surfaces, and the other by rays coming directly to the spectator's eye / [G. Atwood].

Licence: Public Domain Mark

Credit: A general theory for the mensuration of the angle subtended by two objects, of which one is observed by rays after two reflections from plane surfaces, and the other by rays coming directly to the spectator's eye / [G. Atwood]. Source: Wellcome Collection.