MAGAZINE OF SCIENCE AND ART. 
249 
All Artesian wells are on one principle, as far 
as their construction is concerned, but the flow 
of waters is caused by two kinds of pressure : 
pressure produced by the geological structure of 
the locality, and pressure by self-action as a body 
of liquid, consequently some wells are not at all 
depending on geological pressure, but entirely on 
the altitude of the course of supply. 
The most remarkable Artesian well is that at 
Grenelle, near Paris, its depth is 1806 feet, it was 
completed in JS41, and has since continued to 
yield at the rate of 600,000 gallons per hour. The 
opportunity of ascertaining the temperature of the 
earth was not neglected, thermometers indicated 
74° F., at a depth of 442 yards, and at 550 yards it 
stood at 79° ; at the depth finally arrived at, of 
1806 feet, the temperature of the water, which rose 
to the surface, was 81°, corroborating previous 
calculations on the subject. And now that the 
skilful labours of so many years is completed the 
Parisians regret that the submarine sheet of water 
had not lain 1000 yards beneath the surface, that 
they might have an overflowing stream of water at 
104°, to furnish a cheap supply to their numerous 
hot bath establishments, when the water was 
attained in this well the boring rod descended seve- 
yards, proving the existence of a most extensive 
bed of waters, and I quote this instance to hear me 
out in some assertion which I will make hereafter. 
(See Dr. Ure on Artesian wells.) 
In boring for Artesian wells it is not uncom¬ 
mon, in penetrating through the great or primary 
rock, to tap a spring whose source of supply is at 
a higher altitude, or above the level of the surface 
of the locality, and consequently the water ascends 
to that altitude where resistance overcomes pres¬ 
sure or the level is attained. From this it will be 
seen that in the absence of a test with the boring 
rod geological opinion is not to be relied upon, 
for a surface composed of any description of rock 
is equally as favourable an indication for the 
construction of Artesian wells as any other kind of 
geological strata, and one bore at a considerable- 
depth ough. to be sufficient in each district to test 
the capabilities, and prove beyond doubt its geo¬ 
logical structure. 
From the unevenness of the earth's surface, 
principally caused by the flowing of waters and 
continued drainage, many may be of opinion that 
there is no regularity in its construction ; but in 
this they are quite mistaken, for as the progeny of 
all things, in some one way, resembles the parent, 
so does the tree in its construction resemble the 
earth. If we examine a tree we find it composed of 
rings or layers of wood, each ring indicating a 
period of time, increasing the size, and of course 
increasing the pressure, and in many are to be 
found miniature Artesian wells in the shape of holes 
and incisions to draw off the sap, to serve some use¬ 
ful purpose for mankind . So it is with its parent 
the earth, which is regularly composed of layers of 
clays and rocks, each indicating a period of time ; 
the deeper we penetrate the more compressed the 
substance, and to this pressure may be attributed 
a process of formation which is continually going 
on, that is, the sand and other minerals that now 
float loosely on the surface may, in the course of 
ages, through this process, become solid rock. 
In the many shafts which I have assisted in sink¬ 
ing, or superintended the einking of, after leaving 
the surface I never after met with alluvium or allu¬ 
vial soil. As each strata indicates a period of time, 
and each in quality differing from the other, it is 
from present appearance reasonable to conclude 
that each strata yielded its own peculiar herbage, 
but the absence of alluvium leaves no indication 
of vegetation, and if it were not for other and 
satisfactory proofs we would be apt to conclude 
that in those periods no vegetable substance did 
exist j but, as I have stated, we have other and satis¬ 
factory proofs in the shape of charcoal and petri¬ 
fied wood, and the absence of alluvium is easily 
accounted for when we consider that it is decom¬ 
posed vegetable and other matter, and being per¬ 
fectly soluble it is in course of time carried oft' by 
evaporation, and, therefore, in those strata nothing, 
is left but the original composition— pure mother- 
earth, and , consequently, not even a shadow is 
afforded on which to found an opinion as to the pro¬ 
ducts of each geological strata. 
However, for our present purpose it is sufficient 
to know that there is regularity in its construc¬ 
tion, and that each layer is saturated more or 
less with moisture, the deeper we penetrate the 
greater the pressure, and as pressure and moisture 
engenders heat, this pressure satisfactorily accounts 
for the temperature of the earth and. of course, all 
hot springs not influenced by volcanoes. 
Gravel and sand saturated with water, and rest¬ 
ing on a harder bottom, is a most favourable strata 
for Artesian wells, while a strata of rook at a simi¬ 
lar distance is most unfavourable, for, though it 
may he only a few yards in thicknesss through, its 
area or extent may be many miles, thereby form¬ 
ing a dome or roof, and sustaining in itself a groat 
amount of pressure, which otherwise wou'd affect 
the strata beneath and force the water through the 
conducting pipe. 
The well at Grenelle proves beyond a doubt the 
existence of most extensive beds of submarine 
waters in the bowels of the earth, and to account 
for such with any degree of satisfaction the most 
reasonable conclusion is that they were once exten¬ 
sive volcanoes, now extinct craters filled with 
water by infiltration and hermetically scaled by 
the hand of time, and as we know from the flow of 
waters subject to considerable pressure. The extent 
of such reservoirs can never be satisfactorily 
defined, they, in all piobability, are very extensive 
lakes, or, for what we are likely to know may come 
nearer in magnitude to seas; and it is not at all 
improbable, when we consider the great weight and 
pressure of the ocean, that the process of filtration 
in many cases is the soutce of supply, consequently 
it is very necessary to inquire into the probable 
properties of action which are likely to govern 
such submarine waters, for it does not follow that 
they are subject to similar atmospheric action 
which surface water is governed by. In fact, 
they must be free from those surface laws which 
constitute up and down, for this tendency in sub¬ 
marine waters is entirely governed by pressure, 
and as this pressure must be equal on all sides, no 
matter where the tube is introduced, as it is by 
this law the flow of waters is entirely govern'd, and ' 
the only resistance the weight of atmosphere in the 
tube. Thus, a bladder of water subject to pressure 
is a miniature illustration of a submarine lake. Itj 
then, we can conceive an extensive submarine lake 
we must also admit of the vast body of air which is 
there confine!, and, of course, subject to most 
powerful pressure, and as pressure aud moisture 
engenders heat, and heat expands air, I can easily 
imagine that where such submarine lakes are 
within the influence of the deep set roots of burn- 
