ARTESIAN WELLS. 
441 
Artesian Wells. 
The existence of artesian wells depends upon that of sub¬ 
terranean reservoirs and rivers, and the supply yielded by 
borings is regulated by the abundance of such sources. The 
waters of the earth are, in many cases., derived from superficial 
currents which are seen to pour into chasms opened, as it were, 
expressly for their reception; and in others where no apertures 
in the crust of the earth have been detected, their existence is 
proved by the fact that artesian wells sometimes bring up 
from great depths seeds, leaves, and even living fish, which 
must have been carried down through channels large enough 
to admit a considerable stream. But in general, the sheets 
and currents of water reached by deep boring appear to be 
primarily due to infiltration from highlands where the water is 
first collected in superficial or subterranean reservoirs. By 
means of channels conforming to the dip of the strata, these 
reservoirs communicate with the lower basins, and exert upon 
them a fluid pressure sufficient to raise a column to the sur¬ 
face, whenever an orifice is opened.* The water delivered by 
valleys are of so loose and porous texture, that a great quantity of water 
is absorbed in saturating them before a visible current is formed on their 
surface. In a heavy thunder storm, accompanied by a deluging rain, 
which I witnessed at Mount Sinai in the month of May, a large stream of 
water poured, in an almost continuous cascade, down the steep ravine 
north of the convent, by which travellers sometimes descend from the 
plateau between the two peaks, but after reaching the foot of the moun¬ 
tain, it flowed but a few yards before it was swallowed up in the sands. 
* It is conceivable that in large and shallow subterranean basins the 
superincumbent earth may rest upon the water and be partly supported by 
it. In such case the weight of the earth would be an additional, if not the 
sole, cause of the ascent of the water through the tubes of artesian wells. 
The elasticity of gases in the cavities may also aid in forcing up water. 
A French engineer, M. Mullot, invented a simple method of bringing 
to the surface water from any one of several successive accumulations at 
different depths, or of raising it, unmixed, from two or more of them at 
once. It consists in employing concentric tubes, one within the other, 
leaving a space for the rise of water between them, and reaching each to 
the sheet from which it is intended to draw. 
