Civilisation and Eyesight

Abstract

IT would take too much of your space to discuss at length the theoretical limit of resolving-power as depending upon aperture. The reader may be referred to some papers in the Philosophical Magazine for 1879 and 1880, where he will also find references to the work of other investigators. I will only say that (as indicated by the word fairly in my statement) resolution admits of various degrees. Doubtless a practised observer would judge a star to be double whose components subtend a decidedly smaller angle than two minutes, but he would not see them separated. I purposely rather understated the case. The higher the visual power of civilised men, the less room is there for savages with eyes of equal aperture to surpass them.