1831 .] 
or Artesian Fountains, 
11 
/ 
Such is the basis of our theory of the spouting of subterranean waters : it is 
merely the result of what we daily see in the workings of mines. It is the appli- 
cation of the theory of jets <Teau and syphons. It is, in fine, so simple, and so 
natural, that it is hardly possible to offer one more satisfactory. 
The thermal waters which rise to the surface from the interior of primitive 
formations, owe their springing to the disengagement of compressed gases, which 
react upon the surface of these waters in the same manner as vapour acts upon the 
water in the Eolypile. 
The springing of cold mineral gaseous waters may be assimilated to that of the 
compression fountain. 
The circumstances of springs which flow out upon the declivities of hills, nearly 
at a constant height in stratified countries, and particularly in those composed of 
alternate layers of sand and clay, establish and characterize that disposition of 
water which we have said to be in sheets, and whose origin is due either to sub- 
terranean effusions coming from higher countries, or to infiltrations of snow and rain 
water arrested by these claybeds. 
This sheet of water has been likened, by Professor Hachette *, to a layer of ice 
of a similar form to a layer of clay, sand, or chalk. If the water is considered as 
occurring there between two curved surfaces, such as two sections or basins of 
different diameters, whose upper edges are in a plane, or irregularly indented, or 
partly closed, the liquidity of the water is the cause of the pressure which the 
tube of the bored well measures ; but if, in place of a sheet of fluid water, there 
be supposed a layer of ice, the pressure would resist, and would not be indicated 
by the tube, and it would be changed in its power of cohesion. 
Whatever be the manner in which water spreads under ground, in descending 
from higher to lower grounds, whether in sheets or in veins, stripes or torrents, 
when it happens to meet with an issue of any kind in the ground, it insinuates 
itself into it, and rises to a height corresponding to the level of its point of 
departure, or rather to a height which balances the pressure which the water exercises 
against the walls of the canal which contain it 6 . Hence arise the spouting foun- 
tains or natural jets-d' eau, which occur in secondary formations. 
Whence it follows, that, to obtain a spouting fountain, we must, 1st, Try, 
according to the nature of the ground, at a greater or less depth, to reach a flow 
of water coming from higher basins, and passing along, in the bosom of the earth, 
between compact and impermeable rocks ; 2dly, Afford this water, by means of a 
well artificially bored, the possibility of rising to a height proportional to that of 
the level from which it comes ; and, 3dly, Prevent, by tubes inserted into the 
bored well, the spreading of the ascending water in the surrounding sand, or in the 
cracks and fissures of the rocks traversed by the bore. 
From this it will be seen, that spouting springs may be obtained by means of 
boring, in almost every country that presents in its interior subterranean sheets ot 
water, between the alternating and continuous beds of permeable and inpermeable 
deposits, extending to the country or mountains which contain the reservoirs of 
these water-sheets, and whose bases or slopes are covered by these beds. 
But it is essential to repeat here, that we must not expect to find wells of this 
description everywhere, as has been thoughtlessly asserted ; for, on the one hand, 
the nature of the ground sometimes absolutely prevents it, as in granite districts ; 
and, on the other hand, it is possible that a perforation, made even at a very' small 
4 M. Hachette, Considerations sur I'Ecoulement des Liquides. 
* Memoir by M. Barrois, on Bored Wells : Societd des Sciences de Lille , 1825. 
