Chapter 31: On night

1. _Nox_ is derived from _nocere_ (to injure) because it injures the eyes. And it has the light of the moon and stars in order that it may not be without beauty, and that it may comfort all who work by night, and that the light may be sufficiently tempered for certain creatures that cannot endure the light of the sun.

3. Night is caused either because the sun is worn out with his long journey and is weary when he comes to the last stretch of heaven and blows out his weakened fires; or because he is driven under the lands with the same force with which he carried his light over them, and thus the shadow of the earth makes night. Whence Virgilius says:

Ruit Oceano nox
Involvens umbra magna terramque polumque.