Psalm cvii. 20.
“Measure me a measure of wind.”
2 Esdras.
OVER the great Deep of blue water lies the greater Deep of blue air. And between these two—the Ocean of Air and the Ocean of Water, both dragged earthward by the perpetual pull of gravitation—endless intercourse takes place. Each finds its way in small fragments into the other. There is always water present in the air. There is always air present in the water.
Perhaps the latter fact is not so widely recognised as the former; yet it is equally true. Sea-water contains large supplies of dissolved gases, absorbed by the ocean-surface from the atmosphere, and passed on into lower depths, for the use of creatures living there.
But the presence of water in air is known to us all. When we casually remark, “What a damp day it is!” we mean, “What an amount of water to-day is in the atmosphere!”
Water-vapour, drawn up from Ocean’s broad bosom, is carried far and wide “on the wings of the wind,” to fall as rain where needed; and drying winds in their turn pass over regions where much rain has fallen, to bear away superfluous moisture.
A good deal was said in the last chapter about oceanic currents; and mention was made of Winds as their chief cause.
That the power of wind over water is great, anybody may know who has watched the lashing of the ocean into fury by a gale. But the degree of that power was scarcely grasped, until within the last few years. Rivers and streams in the sea were long ascribed to any cause, except the most weighty of all. No one supposed the immense current-producing force to be that of Wind—not of mere local breezes or gales here and there, but of strong constant winds, which prevail month after month over wide ocean-districts.
When a storm-wind pours up a narrowing gulf, where the sea has no outlet, it often piles the water up in an extraordinary manner. Hurricanes have been known to turn the entire Gulf Stream for a while out of its course, and even to force the waters back so as actually to reverse the current. Once the volume of water, thus checked by a terrific gale, was heaped up some thirty feet above the proper level, which of course caused a fearful deluging of the land.