Barlow, one of the mathematical master-spirits of the age, was bold enough once to doubt this vast power of suction on the part of the ruler of the night; and there were certain wiseacres who, as in the case of Galileo, thought it very religiously dangerous indeed, to attempt to interfere with her privileges.
But, in fact, the phenomenon of the tides is just as easy of explanation by the motion of the earth as it is by the moon's presumed drinking propensities, and, as she is a lady, let us hope she has been belied. The motion of the earth would not affect such narrow bodies of water as the Canadian lakes, but the moon's power of attraction would, if it existed to the extent supposed, be under the necessity of doing it, unless she prefers salt to fresh liquors.
One may venture, now-a-days, to express such a doubt, particularly as Madam Moon is a Pagan deity.
The great lakes are, however, very extraordinary in their way. Let us recollect what I have seen and thought of them.
We will commence with Lake Superior, which is 400 miles in length, 100 miles wide, and 900 feet deep, where it has been sounded. It contains 32,000 square miles of water, and it is 628 feet above the level of the sea.
Lake Michigan is 220 miles long, 60 miles wide, and 1,000 deep, as far as it has been sounded; contains 22,400 square miles, and is 584 feet above tide-water; but it is, in fact, only a large bay of Lake Huron, the grand lake, which is 240 miles long, without it averaging 86 miles in width, also averaging 1,000 feet deep, as far as soundings have been tried, contains 20,400 square miles, and is also about 584 feet above the tidal waters.
Off Saginaw Bay, in this lake, leads have been sunk 1,800 feet, or 1,200 feet below the level of the Atlantic, without finding bottom.
Green Bay, an arm of Michigan, is in itself 106 miles long, 20 miles wide, and contains 2,000 square miles.
Lake St. Clair, 6 feet above Lake Erie, follows Lake Huron; but it is a mere enlargement of the St. Lawrence, of immense size, however, and shallow: it is 20 miles long, 14 wide, 20 feet deep, and contains 360 square miles.
Then comes Lake Erie, the Stormy Lake, which is 240 miles long, 40 miles wide, 408 feet in its deepest part, and contains 9,600 square miles. Lake Erie is 565 feet above tide-water. Its average depth is 85 feet only.