Chapter 1: On the earth

1. The earth is placed in the middle region of the universe, being situated like a center at an equal interval from all parts of heaven; in the singular number it means the whole circle;[345] in the plural[346] the separate parts; and reason gives different names for it; for it is called _terra_ from the upper part where it suffers attrition (_teritur_); _humus_ from the lower and _humid_ part, as for example, under the sea; again, _tellus_, because we take (_tollimus_) its fruits; it is also called _ops_ because it brings opulence.[347] It is likewise called _arva_, from ploughing (_arando_) and cultivating.

[345] _Orbem._

[346] _Terrae._

[347] _Opem fert frugibus._

2. Earth in distinction from water is called dry; since the Scripture says that “God called the dry land, earth”. For dryness is the natural property of earth. Its dampness it gets by its relation to water. As to its motion (earthquakes) some say it is wind in its hollow parts, the force of which causes it to move.

3. Others say that a generative water moves in the lands, and causes them to strike together, _sicut vas_, as Lucretius says. Others have it that the earth is sponge-shaped, and its fallen parts lying in ruins cause all the upper parts to shake. The yawning of the earth also is caused either by the motion of the lower water, or by frequent thunderings, or by winds bursting out of the hollow parts of the earth.