17.(Pg. [74]) When it has arrived at E, what angle will be formed by the lines representing the two forces?
18.(Pg. [74]) What effect will the accelerated motion then produce?
19.(Pg. [75]) What is the form of the earth's orbit, and what circumstances produce this form?
20.(Pg. [75]) What is the consequence as regards the regularity of the earth's motion?
21.(Pg. [75]) What law governs as regards the spaces passed over, and how is this explained by [fig. 4. plate 6]?
22.(Pg. [75]) What is meant by perihelion, and by aphelion?
23.(Pg. [75]) What is the difference of the distance of the earth from the sun, in these two points?
24.(Pg. [76]) At what season of the year is it nearest to, and at what furthest from the sun?
25.(Pg. [76]) What is the mean distance of the earth from the sun?
26.(Pg. [76]) Why is but little effect produced, as regards temperature, by the change of distance?