4. divided the light from darkness—refers to the alternation or succession of the one to the other, produced by the daily revolution of the earth round its axis.

     6. firmament—an expanse—a beating out as a plate of metal: a name given to the atmosphere from its appearing to an observer to be the vault of heaven, supporting the weight of the watery clouds. By the creation of an atmosphere, the lighter parts of the waters which overspread the earth's surface were drawn up and suspended in the visible heavens, while the larger and heavier mass remained below. The air was thus "in the midst of the waters," that is, separated them; and this being the apparent use of it, is the only one mentioned, although the atmosphere serves other uses, as a medium of life and light.

     Ge 1:9-13. THIRD DAY.

     9. let the waters under the heaven be gathered together unto one place—The world was to be rendered a terraqueous globe, and this was effected by a volcanic convulsion on its surface, the upheaving of some parts, the sinking of others, and the formation of vast hollows, into which the waters impetuously rushed, as is graphically described (Ps 104:6-9) [HITCHCOCK]. Thus a large part of the earth was left "dry land," and thus were formed oceans, seas, lakes, and rivers which, though each having its own bed, or channel, are all connected with the sea (Job 38:10; Ec 1:7).