278 



ON THE HYDROLOGY OF THE BASTN 



in the course of twenty-four hours ; and he instances the fact of its rising and falling 

 fourteen inches every four hours in the Bay of Quinte. Other writers, as well as ob- 

 servers, have altogether denied the latter statement, and have attributed the remarkable 

 fluctuations which occasionally occur on Lake Ontario, and on Lake Huron, to other 

 causes ; and have not hesitated to ascribe them to partial and local changes in atmospheric 

 pressure. 



But it was impossible to dispute the fact of great fluctuations existing over a long 

 period, the range of rise and fall in which has occupied several years to complete. And 

 all this will be apparent by reference to a document which has been compiled by Colonel 

 Whittlesea from undoubted facts, the greater part of them having occurred within the 

 memory of persons still living. 



The fluctuation, as may be supposed, is a matter of extreme importance to the various 

 interests which have sprung up on the borders of the lakes, and the great rivers connect- 

 ing them, but to none more than to the canal interests, as in the case of the Erie Canal, 

 at Black Rock, the supply to which canal is derived through its uppermost reach, direct 

 from Lake Erie, and in which the extreme fluctuations that occurred, as recently as in 

 1853, caused very considerable anxiety to the managers of that canal; and the relief from 

 which was only to be found in the deepening of the whole of the canal for about twenty- 

 two miles, the greater part of it through a limestone cutting. 



As to the causes of this class of fluctuations, a great variety of suggestions have been 

 thrown out, and, as it appears to the writer, some degree of unnecessary difficulty sug- 

 gested, as to the explanation of the causes, which we should probably find little difficulty 

 in explaining, and even of predicting the fluctuations, if suitable arrangements existed for 

 obtaining data by a sufficiently extended series of observations upon the quantity, the 

 rate, and the time of the fall of rain and snow, and of all the other meteorological phe- 

 nomena which affect the conversion of the snow into vapor or water. It would be neces- 

 sary to record the prevalence, direction, and continuance of the winds, which are observed 

 to produce the most extraordinary effect on the surface of these lakes, and to which atten- 

 tion has before been called. And, lastly, should be observed the manner and the form of 

 the taking of the ice at the outlets of these great lakes. 



This latter feature appears to have been almost entirely overlooked in the suggestions 

 which have been made to account for the increase or decrease of level in the lakes. But 

 it will at once be apparent that the existence of a broad belt of ice over the whole surface 

 of a rapid river, running at the rate of from three to four miles an hour, must have a 

 great effect in regulating the discharge of that river, and so far modifying its surface. 

 For instance, as at Fort Gratiot, at the foot of Lake Huron, where the river is about nine 

 hundred feet wide, and usually runs at the rate of about three and a half miles per hour 



