1893-94.] 



THE FLUCTUATIONS OF LAKE ONTARIO. 



37 



THE FLUCTUATIONS OF LAKE ONTARIO. 



By Kivas Tully, C. E. 



[Read February lo, i8q^.'\ 



On the 22nd of March, 1879, I read a paper on this subject before the 

 Institute; the fluctuations were from the year 1854 to 1878 inclusive, a 

 period of 25 years. I now propose to extend the observations to the end 

 of 1893, an additional period of 15 years, making a total of 40 years. 



The great lakes of North America are the reservoirs of the water 

 shed which lie between "jG" and 92" west longitude, and 42° and 50° north 

 latitude, running in a diagonal or north-westerly direction, between the 

 •above parallels of longitude and latitude. Since 1878 the survey of the 

 great lakes has been completed by the United States army engineers, and 

 I am enabled to give more correct information with respect to the water 

 surface and water shed of the lakes, than could have been furnished 

 "when I read the first paper. 



Lakes. 



Lake Superior 



St. Mary's River 



Lake Michigan 



Lake Huron and Georgian Bay 



St. Clair River < 



Lake St. Clair 



Detroit River 



Lake Erie 



Niagara River 



Lake Ontario 



Area of 

 Water Surface. 

 Square Miles. 



31,200 



150 



22,450 



23,800 



25 

 410 



25 

 9,960 



15 



7,240 



95i275 



Area of 

 Water Shed. 

 Square Miles. 



51,600 

 800 



37,700 



3r,7oo 

 3,800 

 3,400 

 1,200 



22,700 

 300 



21,600 



174,800 



Aggregate Area 



of Basin. 



Square Miles. 



82,800 

 950 



6c, 1 50 



55,500 

 3>B25 

 3,810 

 1,225 



32,660 



315 

 28,840 



270,075 



The levels of the mean surfaces of the lakes above the mean sea level 

 at Governor's Island, New York, are as follows : — Lake Ontario 246y%- 

 feet, Lake Erie 572^^ feet, lakes Huron and Michigan 58 ly'^ feet. Lake 



