134 PROCEEDINGS OF THE AMERICAN ACADEMY 



produced such an accumulation of water. These facts I gathered from 

 Mr. Hulburt, Ashmun, and Peck, old residents of Sault St. Marie. 



" I have witnessed numerous ebbings and flowings of the waters of 

 Lake Superior. 



" In the month of August, 1845, I was coasting in an open boat 

 from Copper Harbour to Eagle River. It was late in the afternoon, 

 and the lake was calm. To the northwest, the clouds indicated that 

 different strata of air were moving in opposite directions. Mirage 

 was beautifully displayed, and I was occupied in tracing out islands, 

 with bold cliffs and spacious harbours, which had no real existence, 

 when suddenly the water about a mile to the northwest was lifted up 

 like a conical hill, to the height of apparently twenty feet, and swept 

 towards the shore, diminishing in size as it advanced. The voyageurs 

 saw it as it came rolling like a great breaker crested with foam, and 

 headed the boat so as to cut the wave. It struck us without doing any 

 injury, and was succeeded by two or three dead swells, when the lake 

 resumed its former tranquillity. The cause which uplifted the water 

 was local, and operated but for a moment. The swell could not, like 

 the lore observed at the mouth of the Amazon, have resulted from 

 opposing currents. 



" While at Rock Harbour, Isle Royal, in the summer of 1847, I 

 witnessed, on one occasion, the alternate rise and fall of the water, 

 recurring at intervals of ten or fifteen minutes, during an entire after- 

 noon. The variation was from twelve to twenty inches. The day was 

 calm and clear, but the barometer was falling. Before the expiration 

 of forty-eight hours, a violent gale set in. 



" On the 23d of July last, I went from Copper Harbour to Eagle 

 River, where I arrived in the evening. The day had been calm, so 

 much so that a sail was useless. In the evening, there sprang up an 

 off-land breeze, as is frequent ; but notwithstanding, I observed a 

 strong current flowing into Eagle River. The next day, a storm came 

 on which continued for several days. 



" I have witnessed the ebb and flow of the water through the narrow 

 inlets and estuaries, particularly at Copper Harbour, when there was 

 not a breath of wind on the lake. Similar phenomena have been 

 noticed on the Swiss Lakes Constance and Geneva, which are there 

 called seiches. 



" I have already given Charlevoix's theory to account for them. 

 Volney supposed that Lake Ontario was the seat of an ancient volcano, 



