And God said, Let there be a firmament in the middle of the waters, and let it divide the waters from the waters.…
The atmosphere, like an ocean, overlies the whole surface of the earth; in fact, it is an ocean; and it is literally true, that, like crabs and lobsters, we live and move and spend our days at the bottom of a sea — an aerial sea. This atmospheric ocean rises far above us, and, like that of waters, has its waves, its currents, and its tides. It is found to grow more rarified, as well as colder, as we ascend towards its upper limit, which is supposed to be about forty-five miles above the level of the sea. Barometrical observations, however, show that on ascending to the height of three and a half miles (nearly that of Cotopaxi), we leave behind us, by weight, more than one-half the whole mass of the atmosphere. And from the experience of aeronauts, it is believed that there is no such air as man can breathe at an elevation of eight miles; probably death would be the certain consequence of exceeding seven, though some, of late, at great risk and suffering, have ascended to nearly that height. On the summit of Mont Blanc, which is a trifle under three miles, the sensations of those who make the ascent are very painful, owing to the levity of the air; the flesh puffs out, the head is oppressed, the respiration is difficult, and the face becomes livid; whilst the temperature is cold almost past endurance. This ocean of air, like that of water, has also its weight and pressure. People, in general, are not aware, because they are not conscious, of any weight resting upon them from the atmosphere; yet reliable experiments prove that at the sea level it presses with a force equal to fourteen and three-fifths pounds on every square inch, or 2,100 pounds on every square foot, or 58,611,548,160 pounds on every square mile; or on the whole surface of the earth with a weight equal to that of a solid globe of lead sixty miles in diameter! How few reflect that they live under an ocean of such stupendous weight! But to bring this fact more sensibly before the mind, we may state that the atmospheric pressure on the whole surface of a medium sized man is no less than fourteen tons — a weight that would instantly crash him, as hollow vessels collapse when sunk deep in the ocean, but for the elasticity and equal pressure of the air on every part without, and the counterbalancing pressure and elasticity of the air within. The air encompassing the earth is a compound substance, made up of two gases, mixed in the proportion of twenty-one parts of oxygen to seventy-nine parts of nitrogen, by measure; mixed with these is a small proportion of carbonic acid gas, which does not exceed one two-thousandth part of the whole volume of the atmosphere. Whether the air is taken from the greatest depths, or the most exalted heights which man has ever reached, this proportion of the oxygen and nitrogen gases is maintained invariably. Considering the vast and varied exhalations that constantly ascend from sea and land, together with the incessant agitation of winds and tempests, this stands before us a most astonishing fact, indeed! But it is not more wonderful than it is important. No possible change could be made in the composition of the air, without rendering it injurious both to animal and vegetable life. If the quantity of nitrogen were but a little increased, all the vital functions of man would be performed with difficulty, pain, and slowness, and the pendulum of life would soon come to a stand. If, on the other hand, the proportion of oxygen were increased, all the processes of life would be quickened into those of a fever, and the animal fabric would soon be destroyed, as it were, by its own fires.
(H. W. Morris, D. D.)
Parallel VersesKJV: And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.