Box 16, Folder 7: Great Lakes, 1867

1 1867 [April ?]

On the supposed

^Subterranean sources of the Waters of the By I. A. Lapham L L. D. of Milwaukee Wis. Great Lakes ^ - Many crude notions exist among ignorant and partially informed persons in regard to the nature and extent of underground streams of water; some supposing the Earth to be full of them; large rivers thus flowing into lakes beneath the surface, or rising in the bottom of the sea. That there are under= =ground streams no one can deny; it is quite true that the upper crust of the Earth is almost every where permeated with water; yet streams of any considerable magnitude "falling away, into the great fissures + chasms," or flowing beneath the surface, ^are of very rare occurence. The water Encountered by the deepeest mines can be managed by a few pumps; and if collected from all the mines in the world, and if we add the water of all the Artesian wells, their united volume would not make a very large river. Some time ago a writer in one of the Chicago newspapers endeavoured to show that Lake Michigan was thus supplied, from subterranean

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Sources, and makes use of arguments and deductions based upon erroneous information to sustain the theory. While this publication was confined to the newspapers, it was scarcely worth while to attempt to correct these Errors and explore the fallicies, but since the article has been reproduced in a very respectable Journal of Science, it is due to the cause of truth, and seems a duty of the Chicago Academy of Sciences, to attempt such correction and Exposition.

Lake Superior is said to have a mean depth of one thousand feet. It so happens that Capt. Bayfield of the British Navy, has made careful soundings of that lake at numerous places, and I copy from his map, a few of the deepest, with their position, as follows:

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Lat. 47 37'N. Long 88 25'W Depth 792 feet

47 58 89 27 678

48 13 89 3 620

47 10 89 55 600

47 31 89 56 600

47 56 87 47 600

48 8 87 43 600

47 7 86 52 600

48 33 87 46 500

47 54 86 39 500

47 15 86 9 486

48 17 88 41 468

47 6 85 40 460

48 35 86 50 400

It will be seen that the greatest depth found was only 792 feet, and hence the mean depth cannot be more than one fourth or one third of the depth stated. The ^mean depth of Lake Michigan is given as nine hundred feet. Whenever soundings shall be made on this lake it is quite probable that its profundity will be equally reduced.

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The assertion is made, of course without proof, that there is not water enough discharged into the Great Lakes to make up for atmospheric absorption and evaporation, while the probabilities are quite the reverse. To sustain this assertion it is said that the Entire state of Wisconsin, even from the borders of Lake Superior, is drained by rivers which flow into, and are tributaries of the Mississippi; while the truth is that only three = fifths of that great state is so drained, the waters of the other two = fifths, including many entire counties, being discharged into the Lakes. In another place, however, after stating that Lake Michigan receives its sole apparent supply from a few streams in the state of Michigan, the Milwaukee river is mentioned as a small stream from Wisconsin! The Fox river of Green Bay, with its abundant flow of water, its manufactories, its steam boat navigation, with a length of 225 miles, and draining an area of 6,700 Square miles is thus, with numerous other streams, ^overlooked.

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It is also asserted, again without the least evidence, that the straits of Mackinaw carry off a large quantity of water from Lake Michigan, which furnishes its due proportion of the great current passing over the Falls of Niagara. Whether the quantity of Water passing out of Lake Michigan during the prevalence of westerly winds, exceeds or falls short of that flowing into it when the winds are from the Eastward, has not yet been ascertained.

The writer is peculiarly unfortunate in selecting the position (Lat. 44 Long. 109) of the great "water producing region of the west;" for the "production" in that region, according to the best rain=charts, is only about one=third or one=half as great as in the vicinity of the Lakes. Large rivers may have their sources in regions not excessively water producing;Minnesota is the mother of the Mississippi, but her climate is dry. There is no evidence of underground rivers flowing from the region of the Rocky Mountains, under several