George Leo Haydock, on Gen 1:6

“And God said: Let there be a firmament made amidst the waters: and let it divide the waters from the waters.”

“A firmament. By this name is here understood the whole space between the earth and the highest stars. The lower part of which divideth the waters that are upon the earth, from those that are above in the clouds. (Challoner) — The Hebrew Rokia is translated stereoma, solidity by the Septuagint., and expansion by most of the moderns. The heavens are often represented as a tent spread out, Psalm. ciii. 3. (Calmet)”

Imported from an open dataset — not yet checked against the printed edition.