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Major Lachlan on the Rise and Fall-of the Lakes. 165 
ues for a considerable length of time, while the maximum con- 
tinues only fora year. . . single individual has informe 
— about 1788 or 1790 the Lakes were nearly as high as in 
“The annual fluctuations in the level of the Lakes are doubt- 
less due to the nature of the seasons, depending on the quantity 
of rain and snow, and the amount of the evaporation ; but it is 
extremity of the Lake, and a corresponding depression there takes 
The prevalence of a strong easterly or northerly wind 
in the same way drives the waters to the western and southern 
parts of the Lake, and a much smaller quantity flows down the 
Niagara during such period. The same effects take place in a 
greater or less degree in all the Lakes—the rising at one extrem- 
ity and the sinking at the other, till the wind subsides, when it 
tesumes the equilibrium, and in so doing presents a beautiful ex- 
hibition of the long swells which are observed in the ocean after 
the subsidence of a high wind.” 
Professor Hall was well seconded by Professor Mather, after- 
wards chief director of the Geological Survey of Ohio, and sub- . 
Sequently (in 1845, ’46, and ’47) a resident on the shores of Lake 
uperior, observant of the meteorology and change of level of 
at Lake, from whose reports and other writings I extract the 
following particulars respecting Lakes Erie and Superior : 
“A tradition exists that there is a periodical rise and fall in Lake 
Erie, through a certain number of years. If it is true—and there 
are reasons for believing that it may be so, to a certain extent— 
* See Geological Report of Professor Mather for 1838. 
