TRANSACTIONS 
OF 
Pie CANADIAN: TNS TIPU EE, 
THE BEUCTUATIONS OF LAKE ONTARIO: 
(SEMI-CENTENARY.) 
BY Kivas, TULLY; C.ES 1.5.0: 
(Read oth January, 1904.) 
THE semi-centenary of the Canadian Institute was celebrated on 
December oth, 1899, His Excellency Lord Minto, Governor-General of 
the Dominion of Canada, and other notabilities being present, the re- 
cords of which were published in the semi-centennial volume of the 
Institute. It is my purpose now to lay before the Institute the parti- 
culars connected with the fluctuation of the waters of Lake Ontario, for 
a period of fifty years. On March 22nd, 1879, I read a paper on this 
subject before the Institute. The fluctuations were from 1854 to 1878 
inclusive, a period of twenty-five years. On February 1oth, 1894, the 
observations were continued to the end of 1893, an additional period of 
fifteen years, making a total of forty years, also read before the Institute. 
In continuing the subject to the end of 1903, for the additional ten 
years, a condensed recapitulation is advisable. The great lakes of North 
America are the reservoirs of the water sheds which lie between 76° and 
92° west longitude, and 42° and 50° north latitude, running in a diagonal 
or north-westerly direction. Since 1878 the survey of the great lakes 
