WHY DO SPEIXGS AND WELLS OVERFLOW? jj 



a well-demonstrated fact that the volume of water escaping from the 

 lakes through the mighty St. Lawrence is far greater than the amount 

 discharged from the upper lakes into Ontario by the proper channels — 

 the St. Clair and Niagara ; and it is also well settled that the supply 

 of Lake Erie from St. Clair is about equaled by its discharge through 

 the Niagara ; showing that it receives from no subterranean source 

 any perceptible surplus of water. And this is generally attributed to 

 its comparative shallowness as compared to the greater depth of Su- 

 perior, Huron, and Ontario " — from Avhich it follows that the immense 

 difference between the outflow and the inflow of Ontario is due to its 

 greater depth, thus making it a possible deep spring ; and that this 

 applies also to the other deep lakes ; and that Superior, Huron, and On- 

 tario, and possibly Michigan, are overflowing springs of subterranean 

 water. The conclusion is therefore inevitable that this great overflow 

 must be accounted for upon some other hypothesis than that of hy- 

 draulic pressure, since there is no higher land which could furnish an 

 adequate supply. Indeed, if we suppose all the land on the continent 

 which is higher than Lake Superior to be but shells tilled with water, 

 the difference between the outflow and inflow of Ontario would ex- 

 haust the supply in a short time. But the subterranean supply is 

 known to be constant, and has always been so. But Mr. Howell sup- 

 poses this vast surplus in Ontario to come through a subterranean 

 channel, connecting it with Superior. And here, again, we must thank 

 Mr. Howell for his facts. The surface of Superior is, he says, 600 

 feet above the sea, and Ontario but 235 above. Therefore, the differ- 

 ence of level between the two is 365 feet. If this channel exists as 

 supposed, the surfaces of these lakes would find a common level, in- 

 stead of a difference of 365 feet ! 



Mr. Howell, in presenting the proof that there is a great under- 

 flow from Superior southward under the valley of the Illinois River, 

 says : " And here on this bank of the old Illinois, oi:)posite the junc- 

 tion of the Fox River, are the celebrated Mineral Springs. . . . These 

 waters are somewhat similar to the waters of Saratoga County, New 

 York," which certainly proves that they do not come from Superior, 

 the waters of which are not of this class. The editor of " Scribner's 

 Monthly " naively adds this note : " Whether the Great Lakes are the 

 true reservoirs from which our Northern wells, springs, and subterra- 

 nean streams receive their constant supply of water, is a question of 

 suflicient interest and significance to merit a thoughtful consideration. 

 The data upon which the advocates of this theory found their conclu- 

 sions are manifold and forcible, and, though there may be breaks in 

 the line of evidence, the facts as now established would seem to favor 

 the views which the author of this paper now proposes to define and 

 defend." While Mr. Howell jiresents strong evidence of a possible 

 underflow from Superior southward, he has hardly claimed that the gen- 

 eral supply of the " Northern wells, springs, and subterranean streams," 



