the water-shed called the Summit, which separates the waters which flow into the St. Lawrence from those which flow into the Gulf of Mexico, and from the southern slope of this Summit, flowing southward, is the Aux Plaines river, a tributary of the Illinois. So that Lake Michigan gets no water from Illinois, but a trifle from Wisconsin, and very little from Michigan. And yet the straits of Mackinaw carry off a large quantity of water from this lake, and Lake Michigan furnishes its due proportion of the great current which passes over the Falls of Niagara. Now the question arises, whence comes this great volume and mass of running water?

Geologists are tolerably familiar with the subject of underground streams and water courses. They know that the crust of the earth is full of these streams, and although from the fact that they are generally concealed from sight, there must be considerable speculation concerning them, yet there are cases, such as in the Mammoth Cave, Kentucky, the Adelsberg mountains in Switzerland, and numerous artesian wells scattered all over the world, the lost rivers on our western prairies, &c., from which a positive knowledge may be derived concerning the nature and history of these rock-bound rivers.

The artesian wells in London furnish now about 12,000,000 of gallons of water daily. This is the seepage of the valley in which the great city is located. The water from the whole country surrounding finds its way along the tilts and inclinations of the broken strata, below the chalk beds, in among the sands and gravel, whence it is taken by boring into the ground to the depth of about 600 feet. It does not appear probable that there are any considerable streams in this vicinity, for the entire of the underlying gravel beds seem, as it were, saturated with water, which is reached at any point of perforation.

These remarks apply to the wells of Grenelle and of Passy, in the basin of Paris, with the exception in the case of the latter that they struck an amazing stream of water eighteen hundred feet below the surface which discharges nearly six millions of gallons per day, rushing to the surface with great power and velocity. This is strong evidence, certainly, of a great underground stream at this point. The great wells of Kissingen in Bavaria, at Munden in Hanover, at Louisville in Kentucky, Charleston, S. C., and hundreds of others, many of which are two thousand feet deep, discharging great volumes of water-all tend to demonstrate the fact that the crust of the earth is penetrated in all directions and at all depths with these streams and water courses.

Adopting this as a conceded fact, let us once more turn to the map of North America and note particularly the point where the thirty-second degree of west longitude crosses the forty-fourth parallel of north latitude. Within a radius of five hundred

miles, of which this is the center, will be found the great water producing region of the West. In this elevated and compara tively uneven surface of the country, nearly all of the great rivers of the West have their sources and fountain-heads. First the Missouri, with its innumerable branches and tributaries, among which are the Yellowstone and the North Fork of the Platte, the Arkansas, the Red River, the Rio Grande, all flowing from the eastern and southern slopes of the Rocky Mountains and finding their way through thousands of miles of country to the Gulf of Mexico. On the western slope is the Rio Colorado, which empties into the Gulf of California, and which is formed by the union of the Grand and Green rivers, the sources of which are also within the territory above mentioned. The same statement is true of the Columbia river flowing through the State of Oregon into the Pacific, and of the other great streams and rivers which flow northward and westward into the Pacific and the Northern oceans. Thus the knowledge we already possess of the surface streams of this great extent of territory all tends to demonstrate the truth of the theory in relation to the water producing region, its location, extent and capacity, and also that on the surface there is but comparatively a small amount of this water which finds its way into our Great Lakes.

It is a well-known fact to travellers on our western plains, that large streams, often rivers in size, suddenly disappear, falling away into great fissures and chasms, sometimes reappearing, but more frequently lost forever; where and in what manner does this water find an outlet? What becomes of the mass of water which falls upon the earth and is absorbed by the soil and the rocks below the beds of rivers and streams? The crust of the earth abounds in water to unknown depths, and from the nature of the element, it must create for itself ways and courses of travel, as plainly beneath as upon the surface. And now, if the Great Lakes are not supplied by means which are upon the the surface and apparent to the eye, it follows as a natural consequence that their sources of supply must be underneath the ground. The outlet of these lakes discharges an enormous quantity of water, the visible inlets are mere trifles in comparisonand thus there seems to be no other conclusion on the subject but that the water supply comes from below the surface of the ground. This water probably finds inlets at different points on the bottoms of the lakes, and maintains the supply with as much certainty and regularity as if the streams were running on the surface of the ground. This theory is further, and I think more particularly demonstrated by the great mass and volume of water which is now being discharged by the Chicago artesian wells. These are over seven hundred feet deep-nearly penetrating the earth to a line parallel with the bottom of Lake Michigan-are located in

no great valley or depression, such as the basins of Paris or London. The water has a head of nearly one hundred and twenty-five feet above the level of the lake; is much colder than the mean temperature of the location of the wells, being now 57 degrees Fahrenheit; these facts tending to show that it must come from a more elevated region of country, and also from a higher latitude. There are two other facts corroborative of this point. When the water was first struck the temperature was 59 degrees Fahrenheit; it has fallen now two degrees, or to 57. Then, the first analysis of the water exhibited 72 grains to the wine gallon of mineral matter held in solution; the second analysis, made only one year afterwards, showed only 56 grains of the same matter. These facts, taken in connection with the great head of the water, seem to establish exclusively that it comes from some remote region of the north or northwest.

It is also probable that the great under ground stream, penetrated by these wells, once discharged its waters into the bottom of Lake Michigan; but this outlet was closed by the upheaval of the earth's crust, which is visible at the point of the location of these wells, and at the present time there is no outlet except the artificial one made by the drill. This supposition is proved by the head and the great force and power of the water, for if it had a lower outlet, anything like the size of the stream, it would not show a head much, if any, above the surface of the ground, and it is also sustained by the facts mentioned abovethe decrease of the temperature of the water from fifty-nine degrees to fifty-seven degrees, and the diminution in quantity of mineral matter held in solution-the latter fact seeming clearly to prove that prior to the time when the drills penetrated the stream, the water had dissolved and absorbed a large quantity of the soluble matter of the rocks with which it came in contact in its state of rest. As soon as an opening or outlet was made, and a quantity of water was discharged, this mineral matter decreased in proportion, and the probability now is that the water will become softer and purer as the amount discharged becomes greater, and that eventually, and probably at no distant day, the water will come from its fountain-head, simply filtered and purified by its passage through the sandstone and gravel

beds.

That the outlet of this stream into Lake Michigan was closed by the upheaval of the earth's crust, is a probable conclusion, which can be verified by an inspection of the grounds on which these wells are located. The surface here is only some seven or eight feet above the level of the surrounding prairie; but geologically or stratigraphically, it is nearly one hundred and fifty feet above the common level of Chicago, that is, at about one mile distant eastward and into the city. We bore

M. C. Lea on Influence of Organic and Inorganic Bodies, etc. 197

into the soil nearly one hundred and fifty feet before reaching the same rock, which is here exposed upon the surface, and at the well bored at the Chicago Distillery Company's premises on the North Branch, they penetrated the Joliet marble at a depth, I believe, of one hundred and eighty-six feet, which, at the other point is only twenty-nine feet from the surface; this and various other facts show the nature and extent of this convulsion, and that it was no difficult feat of nature to dam up this comparatively trifling underground stream, and leave its waters pent up in the rocks and caverns for the future use and benefit of man.

I do not know that these speculations will be of sufficient interest to be made public, but they may have the effect of directing some abler pen to the solution of the problem as to the sources whence the Great Lakes derive their supply of water. Chicago, November, 1866.

ART. XXI.-Experiments on the Influence of various Organic and Inorganic Bodies upon Germination and Vegetation; by M. CAREY LEA, Philadelphia.

THE following experiments were made to determine how far the germination of seeds, and subsequent vegetation of the plants, would be controlled or influenced by the action of acid, alkaline and neutral bodies in solution in the water with which the seeds were moistened. It will be seen that the action of the strongest of our acids is insufficient to prevent germination when sufficiently dilute. And that the same may be said with respect to some of our most powerful oxydizing and reducing agents.

The experiments were made by tying pieces of very thin muslin over glass vessels filled so full that the muslin dipped into the liquid. Grains of wheat were placed on this muslin, an equal number (20 perfect grains) on each. The capacity of the glasses was in every case 12 ounces, and the water was replaced as fast as it evaporated. There was added respectively to each as follows:

5 grs. bromid of ammonium.

8. A pair of zinc and copper plates connected above the surface

by a wire, and plunged in plain water.

AM. JOUR. SCI.-SECOND SERIES, VOL. XLIII, No. 128.—MARCH, 1867.

No. 9. Same, acidulated 3 drops hydrochloric acid.

10. Plain water for comparison.

11.

5 grains sulphite of soda.

chlorate of potassa.

The results were as follows. At the end of

48 hours-Germination evident in all. Most advanced, 4, 10, 11; medium, 2; least, 1, 3, 5, 6, 7, 8, 9, 12.

3 days-Most advanced, 4, 10, 11; medium, 5, 7, 8, 9, 12; least, 1, 2,

3, 6.

4 days-Most advanced, 4, 10, 11; medium, 5, 7, 12; less, 2, 6, 8, 9;

least, 1, 3.

5 days-Most advanced, 4, 10, 11; medium, 5, 6, 7, 8, 12; less, 1, 9; least, 2, 3.

6 days-Most advanced, 4, 10, 11; a little less, 5, 6, 7, 8; much behind, 1, 2, 3, 9.

Some curious deductions are to be drawn from these results. Nitric acid did not at first very strongly affect the growth, less than seven other substances, then eventually its influence became much more felt.

Bicarbonate of potash was the least injurious of all the substances tried, next came sulphite of soda, and next carbonate of soda.

No saline or other substance included acted in any way as a stimulant, the product of the plain water as an average was fully up to any of the rest, though as will hereafter be seen, the largest plant was formed in another vessel.

In the observations just made I have endeavored to show the daily course of action; in the following table I have summed up the total effects at the end of seven days, when experiment was discontinued.

Total results at the end of seven days.