57.(Pg. [102]) Trace the earth from the winter solstice to the vernal equinox, and inform me what changes take place.
58.(Pg. [102]) What takes place at the time of the vernal equinox, and what is meant by the term?
59.(Pg. [102]) In proceeding from the vernal equinox to the summer solstice, what changes take place?
60.(Pg. [103]) From what cause arises the superior heat of the equatorial regions?
61.(Pg. [103]) Why should oblique rays afford less heat than those which are perpendicular?
62.(Pg. [103]) How is this explained by [fig. 1. plate 10]?
63.(Pg. [103]) How do you account for the superior heat of summer, and how is this exemplified in [fig. 2 and 3, plate 10]?
64.(Pg. [104]) What other cause lessens the intensity of oblique rays?
65.(Pg. [104]) How is this explained by [fig. 4]?
66.(Pg. [104]) What causes conspire to lessen the solar heat in the morning and evening?