Schermerhorn—Northern and Northwestern Lakes. 283 
June and July, while on Superior it is delayed until September. 
The average difference, derived from 20 years observation, be- 
tween the high and low water of the year is as follows: 
Lake Superior, 1:2 feet, Michigan and Huron, 1:3, Hrie, 1°6, 
and Ontario, 1°9 feet. 
The highest observed stage of the lakes occurred in the sum- 
mer of 1888, and the lowest in the summer of 1847: the dif- 
ference between the two stages being about 44 feet. 
