A lake that, a moment before, was as smooth as glass suddenly begins to shiver all over as one shivers in a sudden draught. But there is no breeze stirring! A moment later the water rises and falls along the banks; an inch, two inches, a foot, two feet. Then, in the course of a couple of hours, the sky, which before was without a cloud, begins to grow black and there follows a terrific storm. A KIND OF NATURAL BAROMETER The cause of the rising of the water is the heavier pressure of the air at the farther end of the lake, the region of the coming storm. The water, being forced down at one end of the basin, you see, rises at the other. Then as the storm advances toward you the pressure is released and the water falls again; but for a while it rocks to and fro as water will do in a basin if you tip it up at one end and then let it down again. THE TIDES IN A TEACUP But, besides these imitation tides made by the unequal pressure of the wind, lakes have real tides just as the ocean does; and from the same cause, the attraction of the moon. In fact, there are tides in a teacup, and the tea rises toward the passing moon as does everything liquid on the face of the earth. In the teacup the rise is so small you can't see it as you do when the great mass of the ocean waters is moved in the same way. Even in the Great Lakes the tide only amounts to three inches or so. And, in addition to their tides, there are many other things about lakes that have led the largest of them to be referred to as "inland seas." Says Reclus:[39] "Lakes are indeed seas. They have their tempests, their swells, their breakers. It is true the waves are neither so high nor move so rapidly as those of the sea because they do not move over such great depths. They are short, compact and choppy, but for this very reason they are more formidable. And the water being fresh and therefore lighter than that of the ocean is more readily agitated. The wind has scarcely begun to stir when the surface is covered with foaming billows." [Footnote 39: "The Earth."] Not only are lake storms especially dangerous for the reasons just given by the great French geographer but lakes in mountain regions are subject to an additional danger; for their storms are most apt to come at night, just as described in the story of the storm on Galilee in the New Testament. You remember it says the storm came "down."[40] [Footnote 40: Luke 8: 23.] "Now it came to pass on a certain day that Jesus went into a ship with his disciples; and he said unto them, Let us go over unto the other side of the lake. And they launched forth. "But as they sailed he fell asleep: and there came down a storm of wind on the lake; and they were filled with water and were in jeopardy." Macgregor, in his "Rob Roy on the Jordan," draws the following vivid picture of his own struggles with one of these tempests: HOW THE STORM CAME DOWN ON GALILEE