Page:Popular Science Monthly Volume 16.djvu/83

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WHY DO SPRINGS AND WELLS OVERFLOW?
73

may be surprised at the knowledge geologists profess to have acquired respecting the internal structure of the earth, he (the Professor) would endeavor to confirm the above theoretical explanation of the origin and supply of springs by appealing to practical proofs in the proceedings of water companies and well-diggers, and in the pounds, shillings, and pence in the ledgers of manufacturers." It certainly must be a matter of "surprise" to most people that, while the rain-water rarely sank deeper than three feet into the soil, it could yet influence the water-supply to be drawn from deep wells in the earth, so much as to draw upon the water-supply of the river Coin, which like that of all rivers is more or less dependent upon surface influences in addition to overflowing springs. Wells to supply London, the Professor thinks, must not be utilized to draw water from a depth of thirty or forty feet because it would cut off the supply due to the rains which do not sink deeper than three feet! It should have been the easiest possible thing to supply London without in any way drawing upon the supply of the river Coin, since the river and the wells draw from different sources. The learned Professor had no idea of the existence of any force in the premises other than hydrostatic pressure, and yet he proceeds in the next paragraph to give important evidence of some other force:

"In Germany, Mr. Buckmann, of Heilbronn, published in 1835 an octavo volume on artesian wells in the valley of the Keeker, from which it appeared that there were manufactures in Wurtemberg near Constadt where the mills were kept in work during the severest cold of winter by means of the warm water from artesian wells which overflowed into the mill-ponds and prevented them from freezing. And at Heilbronn, also, there were persons who saved the expense of fuel by conducting artesian warm water in pipes through their houses and greenhouses. . . . Let those who doubt go to Grenelle and see the majestic column of warm water from the philosophically discovered fountain rising thirty feet above the surface, at the exact temperature foretold by Arago, and learn the correctness and value of practical deductions from geology applied to the useful purposes of life."

From which quotations it appears that the Professor is in a remarkable position. At Wetford these wells could not be utilized because the river-supply of the Coln would be exhausted; but in Germany they were a new and important source of supply to the rivers themselves. Imagine the "majestic column" at Grenelle rising thirty feet high and the overflow in the other cases being due to hydrostatic pressure—i. e., due to the fact that all these immense floods were the result of a flow from some other higher bodies of water. Why did it not occur to Professor Buckland that, however high and abundant the source, such drains must of necessity have sooner or later exhausted the supply, if no equivalent streams were flowing into that also? But suppose this to be so, whence could come the higher head to flow into and supply that in turn? Carry this on until a flow is secured from the high-