RISE OF WATER BY HYDROSTATIC PRESSURE. 561 
the water is conducted to this depth either by 
percolation through pores and crevices, or by 
small subterraneous channels in these strata, from 
niore elevated distant regions, M'hence it descends, 
until its progress is arrested by the Fault. (See 
Pi. 67. Fig. 2, d, and PI. 6P. Fig. 2, H. L.) 
Besides the advantages that arise to the whole 
of the Animal Creation, from these dispositions 
in the structure of the Earth, whereby natural 
supplies of water are multiplied almost to infinity 
over its surface, a further result, of vast and pe- 
culiar importance to Man, consists in the facili- 
ties which are afforded him of procuring artificial 
wells, throughout those parts of the M'orld which 
are best adapted for human habitation. 
The Causes of the rise of water in ordinary 
artificial wells, are the same that regulate its 
discharge from the natural apertures which give 
origin to springs ; and as both these effects will 
be most intelligibly exemplified, by a considera- 
tion of the causes of the remarkable ascent of 
water to the surface, and often above the surface, 
in those peculiar perforations which are called 
Artesian Wells, our attention may here be pro- 
fitably directed to their history. 
Artesian Wells. 
The name of Artesian Wells is applied to per- 
petually flowing artificial fountains, obtained by 
boring a small hole, through strata that are des- 
G. 
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