Great North American Lakes. 89 



ron, in consequence of the situation of Green Bay, in rela- 

 tion to the former lake. And this appears probable from 

 several circumstances. For in a very short time a considera- 

 ble rise is produced from this cause, even in the smaller 

 lakes. Thus the day that the second expedition under Maj. 

 Long, arrived at the southern extremity of Lake Winnepeck, 

 the water rose in a few hours to the height of nearly three feet 

 in the Bay, on which the fort is situated. — Vol. IL p. 83 — 86. 



It is also stated that since the erection of the pier at Erie, 

 Penn. by which the entrance of the harbour is rendered nar- 

 row and deep, a wind from the opposite shore causes a strong 

 current through this entrance and a proportional rise within 

 the harbour. In the same manner, in consequence of the 

 west and south west vvind, which, agreeably to the journal 

 of Capt. Whiting, prevailed on the 4th of June, the water 

 was driven out of the Bay, and continued low at Fort How- 

 ard until near 7. P. M. By this time, a very considera- 

 ble rise had taken place at the western extremity of Lake 

 Michigan, and the water was of course forced rapidly through 

 the entrance of the Bay, at its north western part, the effect 

 of which would be more sensible at the narrow point, at its 

 head, where the fort is situated. In the same manner a long 

 continued east wind would drive the waters of the Huron 

 through the straits of Michilimackinac, towards the entrance 

 of the Bay, and cause a sensible rise at Fort Howard. 



As the winds are very variable on these lakes both in di- 

 rection and duration, the irregularity of the rise, both as to 

 its height and period, is satisfactorily accounted for ; and 

 hence, on the 5th of June, the rise and fall was frequent, in 

 consequence of the undulations, produced by the wind, on 

 the 4th. 



This, I believe is the manner, in which the supposed tides 

 have generally been accounted for, by those who have often 

 been on these lakes. 



Notes on the tide at the head of Green Bay, made hy Capt. 

 Henry Whiting of the United States Army, in 1819. 



Immediately after our arrival at Fort Howard, the phe- 

 nomenon of a visible tide at that place attracted my atten- 

 tion. It was at once perceivable, that there was a daily 

 change in the level of the river, and f determined to make 

 such observations, as the time and place would admit, in or- 



VoL. XVT.— No. 1. 12 



