FLUCTUATIONS OF LEVEL 



TABLE OF WATER LEVELS 



Reduced to an expression of the depth of water 



Here the high water month, from the meagre obserTations liitherto made, is 

 September; and the low water month is March. The streams are numerous, but 

 short and rapid. Their waters soon reach the Lake in the spring, but to counteract 

 this rapidity the season is late. Snow does not entirely disappear from the swamps 

 and gorges of the mountains before the middle of May. The area draining into 

 this Lake is small compared with its extent. There are but three considerable 

 rivers : the St. Louis, Ontonagon, and Michipicoton, the longest of which does not 

 exceed two hundred miles, yet Captain Bayfield states that more than ten times the 

 quantity is received than is discharged at St. Mary's. On account of the small 

 extent of the basin, the spring floods are insufficient to bring the annual rise to 

 its maximum. It requires the additional rains of the summer and the early fall 

 months to effect this. The observations are not sufficient to determine correctly 

 the amount of either the annual or the secular variations. The greates-t measured 

 difference is two feet six inches, that is, from the high water of September, 1851, 

 to the low water of March, 1854. The greatest difference of months in the year 

 1853, is one foot five inches; in 1854 two feet, and in 1855 two feet one inch. 



All those who journeyed along the shores of this Lake in 1845-6, obsei^ed that 

 the summer months were unusually dry. Fires raged in all parts of the country, 

 not upon the mountains only, but in swamps which had been saturated with water 

 so long that large cedaivtrees had grown up and died of old age. In consequence 

 of this the surface of the Lake declined in those years, and in 1847 still more — 

 according to the general estimate tliree feet. 



The position of Sault St. Mary's I am well aware is not a good one for ascer- 

 taining the actual changes that occur in the open Lake. For this purpose Copper 

 Harbor, Eagle river. Rock Harbor on Isle Royal, or Ontonagon would be much 

 preferable. Places on the broad parts of the water, and not at the heads of bays 

 and inlets, are much the best points to observe the fluctuations of level. They 



