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Tides

at that place of about five feet to pass this excess of water. We know from observations made with care that such navigation in the annual quantity of rain often do occur. Need we therefore wonder that there is a periodical rise and fall of the surface of these lakes? There is an annual change of level resulting from the same curve; in winter when the supply of water to the lakes is very [considerably] much diminished, they sink-and during the early part of the summer they attain their greatest elevation, resulting from the melting of snow and the spring rains.

The question whether there is a regular tide on the lakes still remains undecided. That there are strong and variable currents in Lake Michigan has been known ever since the days of Hennepin; and sailors often discover that upon casting anchor their vessels turn around against the wind by the force of this current. This of course will only happen when the wind is light and in a direction opposed to the current. It is evident

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