ee 
Mr Fox on Springs of Water. 69 
conceives it, however, to be highly probable that the greater part of 
the compressed water under the bed of the sea, may find different 
vents through it, and that there may be salt water jets at the 
bottom of the less deep portions of the sea, as well as jets of fresh 
water which have been discovered in some parts of it. 
The water has been found fresh, or only slightly saline, in parts 
of many mines worked far under the sea; and, on the other hand, 
Mr Fox has detected common salt in the water of some of our 
deeper mines situated many miles from the sea; in some water 
taken from the bottom of Poldice copper mine, he found 24 grains 
of salt in a pint ; also a considerable proportion in water from the 
United Mines, and some of the water in both these mines is at 98° 
and 100°, a temperature probably not equalled in any other mine 
in Cornwall; both circumstances seem to indicate that it ascended 
from a considerable depth. Many mineral springs also contain 
much common salt. 
Thus it appears that if fresh water in some places penetrates 
under the bed of the sea, salt water finds its way in others under 
the land; so that there is every reason to believe that they meet 
at different depths in the earth, acting and reacting on each other 
with more or less effect, according to circumstances. And if 
the obstructions be in some places so great as to limit the percolation 
even to drops, still there must be a constant tendency to balance the 
pressures; and the water will escape, if it should find vents in the 
bed of the ocean, where there is a diminished pressure,—it may be 
of miles, or only a few fathoms of salt-water. However small the 
depth of the latter, it will produce a reaction on the water in the 
earth, which may extend to springs ashore, and raise such of them 
more or less above the level of the sea as do not find an easier outlet. 
Thus sea-water, of between 6 and 7 fathoms deep, might raise fresh- 
water 1 foot above its surface, and so in proportion as the depth is 
greater; and it may be more than this, if the temperature of the 
fresh water should much exceed that of the salt. 
But the facilities which the bed of the sea, and very low lands 
may, in some parts, afford for the escape of the compressed water, 
seem, in Mr Fox’s opinion, to be arguments which are more or less 
unfavourable to the adoption of either the sea-water or vapour hy- 
pothesis, to explain the cause of springs on high ground. Nor can 
such springs as have nearly the same temperature as the climate, be 
supposed to depend on any deeply-seated force for the supply of an 
essential proportion of the water that flows from them, because they 
would then have some of the earth’s heat imparted to them ; al- 
though it is not improbable, that such a force may help to sustain 
some of them at certain levels. 
However this may be, Mr Fox considers that the endosmose pro- 
cess which accompanies voltaic action, has its influence on the height 
and purity of springs, since it readily causes water to pass through 
