220 Reports and Proceedings : 
derived from the deoxidation of atmospheric air carried down by 
rain-water, we may imagine the supply of this water to be furnished 
by some mountainous region, perhaps a distant one, and that it 
descends through rents or porous rocks till it encounters some mass 
of heated matter by which it is converted into steam, and then driven 
upwards through a fissure. In its downward passage the water may 
derive its sulphate of lime, chloride of calcium, and other substances 
from the decomposition of the gypseous, saline, calcareous, and other 
constituents of the rocks which it permeates. The greater part of 
the ingredients are common to sea-water, and might suggest the 
theory of a marine origin; but the analysis of the Bath springs by 
Merck and Galloway shows that the relative proportion of the solid 
matter is far from agreeing with that of the sea, the chloride of mag- 
nesium being absolutely in excess, that is, 14 grains of it per gallon 
for 12 of common salt; whereas in sea-water there are 27 grains of 
salt, or chloride of sodium, to 4 of the chloride of magnesium. That 
some mineral springs, however, may derive an inexhaustible supply, 
through rents and porous rocks, from the leaky bed of the ocean, is 
by no means an unreasonable theory, especially if we believe that the 
contiguity of nearly all the active volcanos to the sea is connected 
with the access of salt water to the subterranean foci of volcanic 
heat.’ 
With respect to the presence of carbonic-acid at great depths, Sir 
Charles referred to Bischoff’s belief that its action on the deep-seated 
silicates, giving rise to carbonates, must tend to an increase of bulk 
in the altered rocks, causing local expansion and compression, with 
alteration and displacement of the neighbouring strata; but, accepting 
this agency as probable, he still looks on alternate heating and cool- 
ing of the rock-masses as the chief cause of oscillations and other 
movements in the earth’s crust. 
‘The temperature of the Bath Waters varies in the different 
springs from 117° to 120° F. This, as before stated, is exceptionally 
high, when we duly allow for the great distance of Bath from the 
nearest region of active or recently extinct voleanos and of violent 
earthquakes. The hot springs of Aix-la-Chapelle have a much 
higher temperature, viz. 135° F., but they are situated within forty 
miles of those cones and lava-streams of the Eifel which, though they 
may have spent their force ages before the earliest records of history, 
belong, nevertheless, to the most modern geological period. Bath is 
about 400 miles distant from the same part of Germany, and 440 
from Auvergne-- another volcanic region, the latest eruptions of 
which were geologically coéval with those of the Eifel. When these 
two regions in France and Germany were the theatres of frequent 
convulsions, we may well suppose that England was often more 
rudely shaken than now; and such shocks as that of October last, 
the sound and rocking motion of which caused so great a sensation 
as it traversed the southern part of the island, and seems to have 
been particularly violent in Herefordshire, may be only a languid 
reminder to us of a force of which the energy has been gradually 
dying out.’ 
