Cannon Ball placed in the Pipe of an Artesian Well is violently ejected by the ascending stream.

In some places application has been made to economical purposes, of the higher temperature of the water rising from great depths. In Wurtemberg Von Bruckmann has applied the warm water of Artesian wells to heat a paper manufactory at Heilbronn, and to prevent the freezing of common water around his mill wheels. The same practice is also adopted in Alsace, and at Canstadt near Stutgardt. It has even been

D', E', through the clay beds A, B, C, D, E, the water from these beds would rise within a pipe ascending from the perforation, to the levels A", B", C", D", E".

These theoretical Results can never occur to the extent here represented, in consequence of the intersections of the strata by valleys of Denudation, the irregular interposition of Faults, and the varying conditions of the matter composing Dykes.

If a valley were excavated in the stratum M below A", the water of this stratum would overflow into the bottom of this valley, and would never rise on the side of the fault so high as the level H.

Wherever the contact of the Dyke H, L, with the strata M, N, O, P, Q, R, that are intersected by it, is imperfect, an issue is formed, through which the water from these inclined strata will be discharged at the surface by a natural Artesian well; hence a series of Artesian springs will mark the line of contact of the Dyke with the fractured edges of the strata from which the water rises, and the level of the water within these strata will be always approximating to that of the springs at H; but as the permeability of Dykes varies in different parts of their course, their effect in sustaining water within the strata adjacent to them, must be irregular, and the water line within these strata will vary according to circumstances, between the highest possible levels, A, B, C, D, E, and the lowest possible level H.

proposed to apply the heat of ascending springs to the warming of green houses. Artesian wells have long been used in Italy, in the duchy of Modena; they have also been successfully applied in Holland, China,* and N. America. By means of similar wells, it is probable that water may be raised to the surface of many parts of the sandy deserts of Africa and Asia, and it has been in contemplation to construct a series of

* An economical and easy method of sinking Artesian Wells and boring for coal, &c, has recently been practised near Saarbrück, by M. Sellow. Instead of the tardy and costly process of boring with a number of Iron Rods screwed to each other, one heavy Bar of cast Iron about six feet long and four inches in diameter, armed at its lower end with a cutting Chisel, and surrounded by a hollow chamber, to receive through valves, and bring up the detritus of the perforated stratum, is suspended from the end of a strong rope, which passes over a wheel or pulley fixed above the spot in which the hole is made. As this rope is raised up and down over the wheel, its tortion gives to the Bar of Iron a circular motion, sufficient to vary the place of the cutting Chisel at each descent.

When the chamber is full, the whole apparatus is raised quickly to the surface to be unloaded, and is again let down by the action of the same wheel. This process has been long practised in China, from whence the report of its use has been brought to Europe. The Chinese are said to have bored in this manner to the depth of 1000 feet. M. Sellow has with this instrument lately made perforations 18 inches in diameter, and several hundred feet deep, for the purpose of ventilating coal mines at Saarbrück. The general substitution of this method for the costly process of boring with rods of iron, may be of much public importance, especially where water can only be obtained from great depths.

these wells along the main road which crosses the Isthmus of Suez.

I have felt it important thus to enter into the theory of Artesian Wells, because their more frequent adoption will add to the facilities of supplying fresh Water in many regions of the Earth, particularly in low and level districts, where this prime necessary of Life is inaccessible by any other means; and because the theory of their mode of operation explains one of the most important and most common contrivances in the subterraneous economy of the Globe, for the production of natural springs.

By these compound results of the original disposition of the strata and their subsequent disturbances, the entire Crust of the Earth has become one grand and connected Apparatus of Hydraulic Machinery, cooperating incessantly with the Sea and with the Atmosphere, to dispense unfailing supplies of fresh Water over the habitable surface of the Land.*

Among the incidental advantages arising to Man from the introduction of Faults and Dislocations of the strata, into the system of curious arrangements that pervade the subterranean eco

* The causes of intermitting Springs, and ebbing and flowing wells, and many minor irregularities in the Hydraulic Action of natural vents of water, depend on local Accidents, such as the interposition of Syphons, Cavities, &c., which are scarcely of sufficient importance to be noticed, in the general view we are here taking of the Causes of the Origin of Springs.

nomy of the Globe, we may further include the circumstance, that these fractures are the most frequent channels of issue to mineral and thermal waters, whose medicinal virtues alleviate many of the diseases of the Human Frame.*

"Thus in the whole machinery of Springs and Rivers, and the apparatus that is kept in action for their duration, through the instrumentality of a system of curiously constructed hills and valleys, receiving their supply occasionally from the rains of heaven, and treasuring it up in their everlasting storehouses to be dispensed perpetually by thousands of never-failing fountains, we see a provision not less striking, than it is important. So also in the adjustment of the relative quantities of Sea and Land, in such due proportions as to supply the earth by constant evaporation, without diminishing the waters of the ocean; and in the appointment of the Atmosphere to be the vehicle of this wonderful and unceasing circulation; in thus separating these waters from their native salt, (which though of the highest utility to preserve the purity of the

Dr. Daubeny has shewn that a large proportion of the thermal springs with which we are acquainted, arise through fractures situated on the great lines of dislocation of the strata. See Daubeny on Thermal Springs, Edin. Phil. Jour. April, 1832, p. 49.

Professor Hoffmann has given examples of these fractures in the axis of valleys of elevation, through which chalybeate waters rise at Pyrmont, and in other valleys of Westphalia. See Pl. 67, fig. 2.

sea, renders them unfit for the support of terreof trial animals or vegetables), and transmitting them in genial showers to scatter fertility over the earth, and maintain the never-failing reservoirs of those springs and rivers by which they are again returned to mix with their parent ocean; in all these circumstances we find such evidence of nicely balanced adaptation of means to ends, of wise foresight, and benevolent intention, and infinite power, that he must be blind indeed, who refuses to recognize in them proofs of the most exalted attributes of the Creator."

CHAPTER XXIII.

Proofs of Design in the Structure and Composition of unorganized Mineral Bodies.

MUCH of the physical history of the compound forms of unorganized mineral bodies, has been anticipated in the considerations given in our early chapters to the unstratified and crystalline rocks. It remains only to say a few words respecting the simple minerals that form the ingredients of these rocks, and the elementary bodies of which they are composed.†

* Buckland, Inaug. Lecture, p. 13.

The term simple mineral is applied not only to uncombined mineral substances, which are rare in Nature, such as pure native