Day two. The work of this day consisted in the formation of that immense gaseous ocean, called the atmosphere, by which the earth is encircled. And God said, Let there be a firmament (rakiya, an expand, from rakah, to beat out; LXX; ??琯?琯챙 ?關慣; Vulgate, firmamentum) in the midst of the waters. To affirm with Knobel, Gesenius, and others that the Hebrews supposed the atmospheric heavens to be a metallic substance (Exodus 24:10), a vault fixed on the water-flood which surrounds the earth (Proverbs 8:27), firm as a molten looking-glass (Job 37:18), borne by the highest mountains, which are therefore called the pillars and foundations of heaven (2혻Samuel 22:8), and having doors and windows (Genesis 7:11; Genesis 28:17; Psalms 78:23), is to confound poetical metaphor with literal prose, optical and phenomenal language with strict scientific statement. The Vulgate and English translations of rakiya may convey the idea of solidity, though it is doubtful if ??琯?琯챙 ?關慣 (LXX.) does not signify that which makes firm as well as that which is made firm (McCaul, Wordsworth, W. Lewis), thus referring to the well-known scientific fact that the atmosphere by its weight upon the waters of the sea keeps them down, and by its pressure against our bodies keeps them up; but it is certain that not solidity, but expansiveness, is the idea represented by rakiya (cf. Scottish, tax, to stretch; Job 37:18; Psalms 104:2; Isaiah 40:22).
"The firmament, expanse of liquid, pure,
Transparent, elemental air, diffused
In circuit to the uttermost convex Of this great round."
(Milton, 'Par. Lost,' Bk. 7.)
And let it divide the waters from the waters. What these waters were, which were designed to be parted by the atmospheric firmament, is explained in the verse which follows.