1843.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



face. In this hypothesis all the mechanism of ascension derives its impelus 

 from this force of pressure. The origin of the water is a matter of indiffer- 

 ence, it may have come from Langres, from the Vosges, or from the Jura 

 mountains; its complete inertia is the same when it has arrived in the centre 

 of the basin, beneath the abattoirs of Grenelle. The process of filtration, 

 wlrch lias brought it to this place, gives it at least no inclination to ascend ; 

 it has, therefore, waited patiently to be impressed by superior masses, in the 

 same way as the fluid, which is motionless in the body of a pump, waits only 

 the action of the piston to force it upwards. But to produce this discharge, 

 the piston must move— it must, in reality, press upon the water which it 

 brings or sends up — in fact, it must work up and down in the barrel of 

 the pump, filling at each successive point of its motion the whole area of the 

 barrel. If we suppose that the subterranean sheets of water rise only because 

 they are pressed by the solid masses above 'them, we must also suppose that 

 these masses really act, as no ascension can be obtained except on this condi- 

 tion ; that they actually fall, so that, in digging the well of Grenelle, there 

 finding water 1600 feet below the surface and causing it to flow impetu- 

 ously more than 80 feet above the surface, M. Mulot would have expended so 

 much art and courage only to provoke a disastrous crash ill the strata be- 

 neath Paris. Evidently, however, and very happily, we may add, this has 

 not been the result. The laws of gravity are universally the same. Place 

 on the surface of the earth a sheet of water of any extent ; fill, for example, 

 the basin of the Champ de Mars with a body of water which shall remain 

 there ; endeavour then to gain dominion over this sheet, of tranquil water 

 through solid masses of chalk or clay. In order that these masses shall re- 

 main in position superimposed on the stagnant water, they must be fashioned 

 into vaults and arches, and there they will be supported without pressing upon 

 the water of the basin. If, for a single instant, they should rest upon this 

 water, they would inevitably sink and be submerged in it, and the result 

 would be a chaos of debris saturated with water. But in the bosom of the 

 earth no solid masses are found in the shape of vaults, neither are there any 

 sheets of water, either confined or at liberty. It is true there are here and 

 there, in the cavities of rocks, in subterraneous grottos, and at the foot of all 

 great mountains, a few pools of water, or more often there are rivulets fed by 

 the infiltration of rain water, and serving to supply fountains which rise at a 

 short distance, and which generally contribute to the formation of streams 

 and rivers. But nearly all these are found on the surface, none of them can 

 occupy a space of any extent in the lower beds of the earth, because they 

 would soon fill up such spaces, by depositing the sand which they bring with 

 them. Besides, in any case the subterranean waters impelled only by a 

 broken, unequal, irregular movement, would have no disposition like those 

 of a jet d'eau to rise above the inclined bed over which they had flowed. A 

 jet d'eau in exercise is in fact a pendulum, it is free and regular in its move- 

 ments, its mechanism is the same, and the same cause produces it. 



Now if a pendulum, starting from any altitude whatever, should meet in the 

 course of its descent towards the vertical line, any obstacles which retard it, 

 the motion will either stop at this vertical line, or at least the oscillation 

 will be very feeble, since it will correspond to that feeble force of acceleration 

 which the obstacle may not have entirely destroyed. In the same manner, 

 the liquid pendulum, that is, the column of water, throughout its descent to 

 a horizontal situation, rigorously requires, in order to an equal rise in the 

 ascending branch, that all its motion and all its acceleration should be truly 

 effected in a continuous canal, entirely filled by the water itself, by the water 

 alone, and that so perfectly as to be inaccessible even to atmospheric air. 



We shall now describe a simple and conclusive experiment. Upon the 

 bottom of a basin, place an upright tube with an opening entirely through 

 it ; and on some stormy day fix the basin beneath the water pipe of a house. 

 The tube will be found to contain some water at its lower end, but only to the 

 height of that which is also found in the basin around it. Not a single drop 

 Will rise above this level because all the force of its fall is expended on the 

 basin itself. But let us now replace the straight tube by one which is curved 

 upwards from its lower extremity, and we shall find that the force of the fall, 

 being confined to the continued column of water which must entirely fill the 

 tube, will cause the water to rise in the ascending branch to the same height 

 as the top of the descending branch. We have now then constructed a real 

 jet d'eau, because we have made use of the only apparatus which can pro- 

 duce one. 



83 



It lsqnite certain that the crust of this earih no where contains an appa- 

 ratus of this kind ; the flowing of an Artesian well cannot therefore be assi- 

 milated to a jet d'eau. Some other explanation then must be sought, and 

 in order to be satisfactory, it must be one which answers all the conditions of 

 the phenomena. 



The explanation we are about to give is necessarily of this kind, since it is 

 derived from an universal principle of nature. 



Chapter 1.1. 

 The true explanation. 



The globe which we inhabit is manifestly a focus of action and heat, 

 which has its greatest energy at the centre of the mass, and which, from 

 this central point, works incessantly to carry matter from the interior to 

 every point of the surface, and which, in this constant effort, meets with a 

 gradually increasing resistance from the successive strata composing the 

 crust of the earth. 



This exterior resistance constrains the central fire to divide and attenuate 

 the matter of the interior, and to sift it, as it were, in minute particles through 

 the pores of the general envelope. 



From this internal elaboration, and this subtile oozing out, arises the con- 

 tinual emission of interior caloric, an emission which necessarily takes place 

 in a radiating form ; that is to say, each jet or steam of caloric escapes and 

 flies off in a direction perpendicular to the surface. Here then is the first ana- 

 logy with the vertical stream of water which issues from an Artesian well. Bat h 

 pore in the terrestial covering is an Artesian well of caloric : and so again 

 is each pore in the surface of every star in heaven an Artesian well of light. 

 These Artesian pores in the crust of the earth being infinitely numerous, it 

 is through these that the central fire impels, in a state of the most minute 

 subdivision, a great part of its interior contents. 



This way of escape, however, is not every where sufficient ; the central 

 action does not appear to succeed in attenuating every substance to such a 

 degree as to effect its expulsion through such exquisitely minute apertures. 

 At many places under the terrestial covering, opposing masses are crowded 

 together, some in a state of gas, others in a vapoury state, others again in a 

 liquid form, and others possessing the consistency of soli Is, but at the same 

 time broken and confusedly mixed together ; and all these substances, 

 whether gases, vapours, liquids or solids, are agitated by a movement whose 

 impetuosity equals its disorder. 



The time is now come when the exterior resistance is suddenly con- 

 quered ; the crust cracks — ^volcano is open, and its centre shoots forth im- 

 mense jets, at first of gas and vapour, then of liquid water, then of burning 

 lava. It is a frightful pit, suddenly thrown out by the irritation of the cen- 

 tral fire. 



We know that the volcanoes of Iceland frequently vomit forth torrents of 

 gas, vapour, and liquid water, which cannot have come from the sea. as its 

 composition is different from that of sea water. 



Let us imagine, for a moment, what would happen if at the instant when 

 a volcano was about to burst forth, its crater could be contracted into a 

 straight tube like that of Grenelle! What a magnificent Artesian well 

 would then be displayed ! What force and height would there be in the jet 

 sent forth ! 



But let us not forget that every volcano is a kind of relief and vent for 

 the interior tumult of the earth. It resembles the pimples and boils on the 

 skins of men and animals. In the normal or regular state, the volcano is 

 silent, and so in a state of health is our skin smooth and sound. 



Thus, at the present time, when no terrestrial volcano is in a state of for- 

 midable eruption, the globe, like a sound and healthy man, quietly and uni- 

 formly transpires through every microscopic or ening in its surface, the super- 

 abundance of its interior productions ; and under their general covering 

 these productions are chemically elaborated, so that each may occupy its 

 proper region. The water in a state of vapour, which is directly formed ID 

 the bowels of the earth, even finds a passage through strata of the denser 

 character. If near the surface it meets with argillaceous masses, it requires 

 an increase of effort to traverse them. Below these the vapour thickens, 

 condenses, and takes at length the liquid form ; and then, far from being op- 



