17.(Pg. [172]) By what experiment can you prove that a separate image of an object is formed in each eye?
18.(Pg. [172]) Under what circumstances are objects seen double?
19.(Pg. [172]) Why is not the image of an object inverted in the common mirror?
20.(Pg. [172]) Your whole figure may be seen in a looking-glass, which is not more than half your height; how is this shown in [fig. 3. plate 17]?
21.(Pg. [173]) Why is the image invisible to the person, when not standing directly before the glass?
22.(Pg. [173]) In what situation may a second person see the image reflected?
23.(Pg. [173]) In what direction will an object always appear to the eye?
24.(Pg. [173]) How is this explained by [fig. 4, plate 17]?
25.(Pg. [173]) What is it that reflects the rays in a looking-glass?
26.(Pg. [174]) All opaque bodies reflect some light, why do they not all act as mirrors?