Nature. Vol. VII, No. 167 January 9, 1873

Nature. Vol. VII, No. 167 January 9, 1873 London: Macmillan Journals, January 9, 1873 https://digital.library.wisc.edu/1711.dl/LBXITYVRTMAPI83 Based on date of publication, this material is presumed to be in the public domain. For information on re-use, see: http://digital.library.wisc.edu/1711.dl/Copyright The libraries provide public access to a wide range of material, including online exhibits, digitized collections, archival finding aids, our catalog, online articles, and a growing range of materials in many media. When possible, we provide rights information in catalog records, finding aids, and other metadata that accompanies collections or items. However, it is always the user's obligation to evaluate copyright and rights issues in light of their own use. 728 State Street | Madison, Wisconsin 53706 | library.wisc.edu Wii. ein es se te NATUR: Fy. (77 me ee ; of water they allow to pass through them. A bed of sind, THURSDAY JANUARY 9, 1873 for example, is pervious, that Is, will let) water sink through it readily, because the little grains of san lie loosely together, touching each other only at some points, ~ | so as to leave empty spaces between. The water readily finds its way among these empty spaces. In fact, the DEEP SPRINGS sand-bed may become a kind of sponge, quite saturated oo, . with the water which has filtered down from the surfacc. A° our contribution to a controversy which has now | A bed of clay, on the other hand, is impervious; it is + been going on for some weeks in the 77s, and | made up of very sinall pzrticles fitting closely to each to which much public attention has been given, we have | other, and therefore offering resistance to the passage of received Prof. Geikic’s permission to print a Lesson | water. Wherever such a bed occurs, it hinders the free from his forthcoming Primer of Physical Geography | P458@s© of the water, which, unable to sink through it . ; > , Oo from above on the way down, or from below on the way dealing with the subject of Deep Springs. up to the surface again, is kept in by the clay, and forced The facts which Prof. Geikic here summarises in so | to find another line of escape. admirable a manner, taken in connection with what has “Sandy or gravelly soils are dry because the rain at already appeared in NATURE as to what one may almost | once sinks through them ; clay soils are wet because they call the cosmical connections of the recent rainfall, and | Tetain the water, and prevent it from freely descending the e actual conditions of the case placed before the | '*° the earth. P “When water from rain or melted snow sinks below readers of the Yves by Mr. Bailey Denton, should, we } the surface into the soil, or into rock, it does not remain think, be enough to convince all that there is a science in | at rest there. If you were to dig a deep hole in the these matters, and that the way in which Nature is in the ; ground you would soon find that the water which lies habit of working should be at least understood, if even in perce the particles would begin to. trickle our of pe 5 . : sides of your excavation, and gather into a pool in the only a feeble way, before a protest be entered against bottom. "TE you baled the water out it would still keep her. ; ; oozing from the sides, and the pool would ere long be Do we wish to continue to avail ourselves of surface | fJJed again. This would show you that the underground springs? If so it must be remembered, first, that these | water will readily flow into any open channel which it can are impossible without the deep springs of which Prof. | reach. a Geikie speaks ; secondly, that it may be roughly hat th normally said, Now the rocks beneath us, besides being uy many replenished once a vear, and that | C28¢5 Porous in their texture, such as san stone, are that they are y rep year, all more or less traversed with cracks—sometimes in some parts of England there has not been rain enough | mere lines, like those of a cracked window-pane, but this year yet to replenish them. In the words of Mr. | sometimes wide and open clefts and tunnels. These Denton :— numerous channels serve as passages for the underground water. Hence, although a rock may be so “During the summer months, from May to October, } hard and close-grained that water does not soak through the rain which falls seldom reaches the depth of a yard. | it at all, yet if that rock is plentifully supplied with these This has been clearly shown by Dickinson’s records. | cracks, it may allow a large quantity of water to pass During that period evaporation, exceeding the rainfall through. Limestone, for example, is a very hard rock, very considerably, draws upon the subterranean supply of | through the grains of which water can make but little water stored in the soil, and in continued drought the | way; yet itis so full of cracks or ‘joints,’ draught as they are is immense. In the winter months, from October | called, and these joints are often so wide, that they give to May, when the rainfall exceeds the evaporation, the | passage to a great deal of water. excess penetrates the earth, and having saturated the “In hilly districts, where the surface of the ground subsoil as it passes through it, the surplus descends to | has not been brought under the plough, you will the springs or subterranean level to replenish the one and | notice that many places are marshy and wet, even raise the other. To produce this super-saturation requires | when the weather has long been dry. time, The soil every- and hence it is that ‘ mid-winter’—7¢. the shortest | where around has perhaps been baked day—is reached quite hard by before the deep springs and deep water- | the sun ; but these places remain still wet in spite of beds are augmented.” the heat. Whence do they get their water? Plainly not ; . .. ., | directly from the air; for in that case the rest of the The present controversy will do lasting good if it ground would also be damp. They get it not from above, induces, and we think it may, accurate observations of | but from below. It is oozing out of the ground : the amount and it of water in the deep springs in different | is this constant outcome of water from areas in different below which keeps years, and at diffcrent times of the | the ground wet and marshy. In other places you will year. Itis morethan possible that the late heavy rainfall : . observe that the water does xe merely of through the . € yj - ‘festa. ground, Dut gives rise to a tte runne of clear water. is even, from the deep spring point of view, a manifes If you follow such a runnel up to its source, you will see tion of a highcr law—or of a miracle as Mr. Babbage would | that it comes gushing out of the ground as a Spring. have called it—that nature may not only replenish our “Springs are the natural outlets for the underground underground cisterns every year, but vary the yearly | water. But you ask why should this water have any supply, over a period of eleven years or sv, oT he eubjoined “po 9. insane Une My repeats h way in . 0. vure ‘iy, Professor Geikic’s presents e way ot “ Lesson ” runs as follows :-— which many rocks lie with “regard to each other, and “In this lesson we are to follow the course of that part | in which you would meet with them if you Were to of the rain which sinks below ground. A little attention | cut a long deep trench or section beneath the surface. to the soils and rocks which form the surface of a} They are arranged, as you see, in flat layers or beds, country is enough to show that they differ greatly from | Let us suppose that a is a flat layer of some imper- each othcr in hardness, and in texture or grain, Some | vious rock, like clay, and & another layer of a porous are quite loosc and porous, others are tough and close- | material, like sand. ‘The rain which falls on the. sur- grained. They consequently differ much in the quantity | face of the ground, and sinks through the upper bed, No. 167—VOL, VI L itt [ Fan. 9, 1873 NATURE 178 Mines, pits, dug to catch this water. cither to | Wells, are actually kind, are usually lower one, and made deep excavations of any will be arrested by the of that | quarries, and kept dry by having it its escape along the surface with it, and need to be gather there, or find have its bottom troubled a hollow or valley should out.” lower bed. If the water flows, | pumpcd . of the line along which . , that, as Science gets more below the level sides of the valley, as is a satisfaction to think will gush out along the of escape may be It as springs the woodcut. The line education, such a question shown atssin infused into our general will not be between two different attention is now directed as in this case, the junction already | the one to which ; for either, of the numerous joints bearings are understood kinds of rock, or some flow- | mooted until its scientific of the be, the water cannot help deep springs is only onc referred to, Whatever it after all the question of in the controversy.

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