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 on land and sea. Without this great agent no visible motion would ever take place in the sea. Its great currents, indeed, might flow on (though even that is questionable), but its surface would never present any other aspect than that of an unruffled sheet of clear glass. The air, then, becomes in this place an appropriate subject of consideration. The Voice of Ocean has something very emphatic to say about the atmosphere.

In regard to its nature, it is sufficient to say that atmospheric air is composed of two gases—oxygen and nitrogen. Like the sea, the atmosphere is an ocean which flows, not in chaotic confusion, but in regular, appointed courses; acting in obedience to the fixed, unvarying laws of the Almighty, and having currents, counter-currents, and eddies also, just like the watery ocean, which exercise a specific and salutary influence where they exist.

The offices of the atmosphere are thus quaintly enumerated by Maury:—"The atmosphere is an envelope or covering for the distribution of light and heat over the Earth; it is a sewer into which, with every breath we draw, we cast vast quantities of dead animal matter; it is a laboratory for purification, in which that matter is recompounded, and wrought again into wholesome and healthful shapes; it is a machine for pumping up all the rivers from the sea, and for conveying the water from the ocean to their sources in the mountains. It is an inexhaustible magazine, marvellously stored; and