17.(Pg. [93]) What is meant by the term zone; and are the frigid zones properly so called?
18.(Pg. [93]) How do meridian lines extend, and what is meant by the meridian of a place?
19.(Pg. [93]) What is said of the meridian to which the sun is opposite, and where is it then midnight?
20.(Pg. [94]) What hour is it then, at places exactly half way between these meridians?
21.(Pg. [94]) How are greater and lesser circles distinguished?
22.(Pg. [94]) What part of a circle is a degree, and how are these further divided?
23.(Pg. [94]) What is the diameter, and what the circumference of a circle, and what proportion do they bear to each other?
24.(Pg. [94]) What part of a circle is a meridian?
25.(Pg. [94]) How many degrees are there between the equator and the poles?
26.(Pg. [94]) Into what parts, besides degrees, is the ecliptic divided?