the Great Lakes of America. 295 



feet above the present level of the lake; and he says that 

 every spring you may pass up the Chicago River and carry 

 in the shoalest place five feet water into the Illinois, and from 

 thence into the Mississippi.*" 



Mackenzie, in his account of his Voyages through the Con- 

 tinent to the Frozen and Pacific Oceans, in 1789 and 1793, 

 says, that " along the surrounding branches of Lake Superior ' 

 there are evident marks of the decrease of its waters by the lines 

 observable along them. The space, however, between the 

 highest and the lowest is not so great as in the smaller lakes, 

 as it does not amount to more than six feet ; the former, or 

 highest lines, are very faint."" 



4. The lakes are subject to extraordinary swells and risings. 

 On the 18th of October 1 764, Colonel Bradstreet, who had been 

 on an expedition against the Western Indians, broke up liis 

 camp at Sandusky to proceed on his return to Albany by Lake 

 Erie. In the evening, as he was going to land the troops, a 

 sudden swell of the lake, without any visible cause, destroyed 

 several of his boats, but no lives were lost. This extraordinary 

 event was, however, looked upon as the precursor of a storm, 

 and accordingly one soon occurred, which lasted several days. 

 Mackenzie, before quoted, states that a very curious phenome- 

 non was observed some years ago at the Grand Portage in Lake 

 Superior, for which no obvious cause could be assigned. " The 

 water withdrew with great precipitation, leaving the ground dry 

 that had never before been visible ; the fall being equal to four 

 perpendicular feet, and rushing back with great velocity above 

 the common mark. It continued thus falling and rising for 

 several hours, gradually decreasing until it stopped at his usual 

 height." 



The following occurrence, equally extraordinary, took place 

 on the British side of Lake Erie on or about the 30th May 

 1823, which is thus described. " A little after sunset Lake 

 Erie was observed to take a sudden and extraordinary rise, the 

 weather being fine and clear, and the lake calm and smooth. It 

 was principally noticed at the mouths of Otter and Kettle 

 Creeks, which are twenty miles apart. At Otter Creek it came 

 in, without the least previous intimation, in a swell of nine 

 feet perpendkidar height^ as was afterwards ascertained, rush- 



