13.(Pg. [132]) What is the instrument called, which is represented in [plate 14, fig. 1],—and how does it operate?
14.(Pg. [133]) Why are wells rarely well supplied with water, in elevated situations?
15.(Pg. [133]) When water is found in elevated situations, whence is it supplied?
16.(Pg. [133]) Wells and springs, at some periods well supplied, fail at others; how is this accounted for?
17.(Pg. [134]) Some springs flow abundantly in dry weather, which occasionally fail in wet weather, how may this be explained?
18.(Pg. [134]) What is meant by intermitting springs?
19.(Pg. [134]) Whence do rivers, in general, derive their water?
20.(Pg. [134]) Why do springs abound more in mountainous, than in level countries?
21.(Pg. [135]) How are lakes formed?
22.(Pg. [135]) What causes water to rise in fountains, and how is this explained by [figure 2, plate 14]?