It was stated to us at Michilimackinac, that Lake Huron had fallen one foot during the last year. It was also added that the decrease in the lake waters had been noticed for many years, and that there were, in fact, periodical depressions and refluxes at periods of seven and fourteen years. A little reflection will, however, render it manifest that, in a region of country so extensive and thinly populated, observations must be vaguely made, and that many circumstances may operate to produce deception with respect to the permanent diminution or rise of water, as the prevalence of winds, the quantity of rain and snow which influences these basins, and the periodical distribution of solar heat. It has already been remarked, while at the mouth of Fox River, that a fluctuation, resembling a tide, has been improperly thought to exist there, and, indeed, similar phenomena appear to influence the Baltic. Philosophers have not been wanting, who have attributed similar appearances to the ocean itself. "It has been asserted," observed Cuvier, "that the sea is subject to a continual diminution of its level, and proofs of this are said to have been observed in some parts of the shores of the Baltic. Whatever may have been the cause of these appearances, we certainly know that nothing of the kind has been observed upon our coast, and, consequently, that there has been no general lowering of the waters of the ocean. The most ancient seaports still have their quays and other erections, at the same height above the level of the sea, as at their first construction. Certain general movements have been supposed in the sea, from east to west, or in other directions; but nowhere has any person been able to ascertain their effects with the least degree of precision."[150] [150] Theory of the Earth. Modern geologists attribute these changes to the rising or sinking of the earth from volcanic forces.