33.(Pg. [163]) What circumstance, renders objects seen by moonlight, still less vivid?
34.(Pg. [164]) What is meant by the pupil of the eye?
35.(Pg. [164]) What by the retina?
36.(Pg. [164]) How do the rays of light operate on the eye in producing vision?
37.(Pg. [164]) How may this be exemplified, in a darkened room?
38.(Pg. [164]) What is meant by a camera obscura?
39.(Pg. [164]) How is it explained in [plate 16]?
40.(Pg. [165]) Why are the objects inverted and reversed?
41.(Pg. [165]) What analogy is there between the camera obscura, and the eye?
42.(Pg. [165]) Is it the object, or its picture on the retina, which presents to the mind an idea of the object seen?