No. 7.] WHITTLESEY— LEVELS OF LAKES. 407 



ON FLUCTUATIONS OF LEVEL IN LAKE ERIE. 



By Col. Charles Whittlesey, Cleveland, Ohio 



In this paper I present very little in reference to fluctuations 

 of the surface of Lake Erie, which I have not published 

 heretofore. My principal object is to place on record a 

 resume of those publications, for future reference. The 

 subject was taken up simultaneously in 1838, by the Geological 

 Survey, Ohio, in charge of Professor W. W. Mather, and of 

 Michigan under Dr. Douglass Houghton. When the Survey of 

 Ohio was disbanded in 1839, 1 continued to make occasional obser- 

 vations, and to collect those made by others, until 1859; when 

 the Lake Surveys of the Government, being then in charge of the 

 late General Meade, adopted a general system of water registers. 

 There have been on each Lake since that time two Meteorolo- 

 gical Stations, where readings are taken each day of the height 

 of the water, and all phenomena connected with its fluctuations. 

 These readings will in due time enable the officers of the Survey 

 to discuss the subject, on the basis of reliable facts ; from which 

 alone philosophical conclusions can be reached. 



But prior to 1859 enough had been determined to show, that 

 there is an annual rise and fall of the waters of the Lakes, ana- 

 logous to the high and low water of large rivers, and due to 



precisely the same cause. 



From the head of Lake Superior to the mouth of the St. 



Lawrence, the channel must be regarded as one great river with 

 expansions, which is raised by the surplus water of the rainy 

 season, and depressed by the dry season. It is simply the balance 

 between rainfall and evaporation over the entire valley of the 

 Lakes ; embracing 300,000 square miles. When these two 

 opposite factors shall be obtained by observation, the stage of 

 water can be predicted with as much certainty as the probabi- 

 lities of the seasons, can be deduced from observations on general 

 meteorology. Both follow a law and are nearly parallel to each 

 other. Both run through cycles of change, returning in periods 

 that are closely similar but which are not regular. 



In regard to what I have designated as the general or secular 

 changes of level, as distinguished from the annual, the former 



