"And God said, Let there be a _rāqiā‘_ in the midst of the waters, and let it divide the waters from the waters. And God made the _rāqiā‘_, and divided the waters which were under the _rāqiā‘_ from the waters which were above the _rāqiā‘_: and it was so. And God called the _rāqiā‘_ _Shamayim_. And the evening and the morning were the second day." It is, of course, perfectly clear that by the word _rāqiā‘_ in the preceding passage it is the atmosphere that is alluded to. But later on in the chapter the word is used in a slightly different connection. "God said, Let there be lights in the firmament of heaven." As we look upward from the earth, we look through a twofold medium. Near the earth we have our atmosphere; above that there is inter-stellar space, void of anything, so far as we know, except the Ether. We are not able to detect any line of demarcation where our atmosphere ends, and the outer void begins. Both therefore are equally spoken of as "the firmament"; and yet there is a difference between the two. The lower supports the clouds; in the upper are set the two great lights and the stars. The upper, therefore, is emphatically _reqiā‘ hasshamayim_, "the firmament of heaven," of the "uplifted." It is "in the face of"--that is, "before," or "under the eyes of," "beneath,"--this higher expanse that the fowls of the air fly to and fro. The firmament, then, is that which Tennyson sings of as "the central blue," the seeming vault of the sky, which we can consider as at any height above us that we please. The clouds are above it in one sense; yet in another, sun, moon and stars, which are clearly far higher than the clouds, are set in it. There is no question therefore as to what is referred to by the word "firmament"; but there is a question as to the etymological meaning of the word, and associated with that, a question as to how the Hebrews themselves conceived of the celestial vault.