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 ina 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. II. p. 85—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 wind, 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 
e 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 by 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 I determined to make 
such observations, as the time and place would admit, in or- 
Vor. XVI.—No. 1. 12 
