14 FLUCTUATIONS OF LEVEL 



Lakes, gives to thv public a ])art of his registers taken at the dock at Fort Niagara. 

 The fluctuations of the Niagara river are not exactly coincident with those in the 

 general surface of either the Lake above or the one below; but those reported by 

 Mr. Giddings vary so little that I have reduced them to the same standard as the 

 others and placed them in my abstract. 



From the yearly average 1846 was the lowest, but differed only one-tenth of an 

 inch from 1851. That portion of 1846 which appears in the Oswego tables shows 

 the lowest stage observed there. Like Lake Erie, the spring rise is reached in 

 the months of June and July ; but there is more irregularity in the low water 

 months. 



According to Mr. Spencer's observations, high water occurred in the months of 

 June and July, seven years in eight; the minimum of the year in the months of 

 November and December, four times; January and February, three; and INIarch, 

 once. The records of nineteen years at Oswego show that the month of July, 

 1888, was higher than any month since, which corresponds in time with the noted 

 flood on Lake Erie. From the high level of that year, the decline of Lake Ontario 

 was not as rapid as Lake Erie. The lowest state since 1838 on the last named 

 Lake is that of 1842, but on Lake Ontario that of 1848. 



The question of the existence of a daily or lunar tide in this and other Lakes, 

 corresponding to that of the ocean, has been, like the idea of a seven year's rise and 

 a seven year's fall, so often brought forward that it deserves notice. In AVeld's 

 Travels in Canada, 1790-5, it is stated that "it is believed by many that the waters 

 of Lake Ontario are influenced by a tide that ebbs and flows frequently in the 

 course of twenty-four hours, as in the Bay of Quinte, where it has been observed 

 to rise fourteen inches every four hours." 



The same idea had its origin on Lake INIichigan, at the head of Green Bay, 

 which, like that of Quinte, is a narrow inlet extending far inland. 



Colonel Henry Whiting, of the army, observed the fluctuations at Green Bay, in 

 1828, during the months of July and August, and states that in no case did they 

 correspond to the passage of the moon over the meridian, and that there are no 

 lunar tides. Mr. George C. Davies, who assisted Mr. Walworth in keeping a 

 daily water table at Cleveland, in 1838, says, "I can say, without fear of contradic- 

 tion, that there is no lunar tide on Lake Erie." 



Captain Jonathan Carver, who passed through the Upper Lakes, in 1766-9, 

 states that "observations made by the French at the Straits of Mackinaw show 

 that there is no diurnal flood and ebb there." 



The difficulty of reducing observations made at one port to those made at another, 

 even on the same Lake, is owing to a want of correspondence in the rise and fall 

 of water in the same months at different places. It is also impossible to free the 

 readings from erratic "local oscillations," some of which are due to visible causes, 

 such as winds and the shape of the coast, and others to causes not visible, and not 

 yet well understood. This difficulty is apparent on comparing the means of the 

 same months at different places on Lake Erie, as shown in the table of levels. 

 We have for the years 1838, 1839, 1840, and 1841, pretty fair annual averages at 



