2 FLUCTUATIONS OF LEVEL 



region can be made out, I have no doubt that tliere will be found a direct corre- 

 spondence between the secular fluctuations of the level of the Lakes and the 

 meteorology of the surrounding country. 



When a wet, cold, and cloudy year is succeeded by another of the same character, 

 the reservoirs, into which so many rivers, creeks, and streamlets discharge their 

 waters, gradually fill up. A contrary combination, viz: a series of dry, warm, and 

 clear seasons, by diminishing the supply and increasing evaporation, will produce a 

 visible depression of the surface of the Lakes. To discuss thoroughly the pheno- 

 mena of fluctuation we need daily registers, kept at difl"erent and distant places on 

 each I^ake, for a period of at least twenty-five years. It is probable that within 

 that length of time the seasons complete a cycle, and return to pass again through 

 a similar course of changes. To establish and continue such registers Avould, how- 

 ever, require the assistance of the government. Tlic Topographical Bureau has 

 required its agents at the Lake harbors, in some cases, to keep water tables; and 

 these form the most minute and reliable information we possess. This corps, how- 

 ever, is engaged in harbor constructions only at irregular intervals, and consequently 

 leave in their records many blank spaces. Government has, however, through its 

 light-house keepers, the means of procuring perfect registers of water levels on all 

 the Lakes, with the least possible expense; and there would be little difficulty in 

 pointing out numerous practical results that would justify such a system of obser- 

 vations, without regarding the unseen benefits that always follow the acquisition 

 of scientific knowledge. In this case there are important benefits accruing to 

 commerce, not requiring demonstration. The soundings, made in the prosecution 

 of the hydrographical survey of the Lakes, to be reliable marks for knowing the 

 depth, should be referred to a well determined stage of water. Docks, Avarehouses, 

 and harbor channels derive their value from being at all times accessible to vessels. 

 The tables now presented show extreme changes of level of seven feet ; and from the 

 average of entire months, in difierent years, a difference of five feet three inches. 



There are some vessels on the Lakes that draw more than nine feet, and, there- 

 fore, a dock constructed at the time of high water, into which a vessel of this 

 draught could enter, would require between five and six feet of dredging, in order 

 to be used during low water. 



As a question of science and of utility, the whole subject has engaged the atten- 

 tion of prominent men. De Witt Clinton and General Cass, among others, have 

 bestowed upon it the most careful study. General Henry Whiting, of the army, 

 while residing at Detroit, at and subsequent to the war of 1812, kept the first 

 registers to which we can refer. Dr. Douglass Houghton, the lamented geologist 

 of Michigan, made it one of the objects of his examination during his short but 

 active life. 



I have condensed, from all sources within my reach, information respecting the 

 state of the waters since the settlement of the Lake country. This is put into a 

 tabular form ; but is in many cases based upon general report, upon tradition, and 

 the memory of living Avitnesses, but latterly upon measurements. The authorities 

 are given on the same sheet, so that the value of what it contains may be properly 

 estimated. 



