p.10

10
1859

by the city=built harbor so as to allow a free passage of the waters, as well as of the vessels navigating the lake, it will be found that the current as often runs from the lake into the river as from the river into the lake. When the water of the lake is rising, the current is inwards; when falling it is outwards. Ice on the river is lifted up by the rising water except where it is attached to the banks; and the water finds its way above the ice along either shore. Piles driven into the bed of the river are drawn out by this repeated rising of the solid ice.

(5) The fifth and last change of level of the waters of the lakes is one which was supposed to have a regular period of fourteen years and about which there has been much discussion. That the waters continue to rise for a series of years and then to fall for another [serum?] of years there can be no doubt; but it is now not generally believed that this periodical change is at all regular or measured by any definite time [line?]. As all ribers occasionally rise to an unwouted height and so often fall to an unusually low stage, so the great river passing through these great lakes has its occasional changes. A wet