34.(Pg. [187]) What experiment may be performed with a piece of card, so as to exemplify the compound nature of light?
35.(Pg. [187]) How can the same be shown by a lens, [fig. 5. plate 20]?
36.(Pg. [187]) Is it certain that there are seven primitive colours in the spectrum?
37.(Pg. [188]) How is the rainbow produced, and what is necessary to its production?
38.(Pg. [188]) How are the solar rays affected by a convex lens?
39.(Pg. [188]) Why is such a lens, called a burning glass?
40.(Pg. [188]) Why are bodies of a dark colour, more readily inflamed, than those which are white?
41.(Pg. [189]) What is believed to be the reason, why some bodies absorb more rays than others?
42.(Pg. [189]) What determines the colour of any particular body?
43.(Pg. [189]) What exemplifications are given?