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and the Products of its Transmutation. 135 
1. The abstraction of lime, 
2. The introduction of peroxide of iron, and 
3. The substitution of potash for soda. 
We are ignorant of any other mode in which this trans- 
mutation could be effected than by the agency of the surface 
water, which is continually penetrating through the earth’s 
strata, and which always contains more or less of the sub- 
stances which come into play in this case,—lime, oxide of 
iron, potash, and soda. 
So far as classification is at all applicable to natural’ phe- 
nomena, there appears to be no doubt that the transmutations 
which take place in the above manner in inorganic nature, 
must be separated into such as result from the solvent action 
of water alone, and such as are in a great degree owing to the 
carbonic acid which it holds in solution. The decomposition 
of felspar and other alkaline silicates is an example of the 
former class. The decomposition of calcareous silicates, re- 
quiring the conjoint agency of carbonic acid, is an example 
of the latter class. There is every reason to believe that, 
when water containing carbonic acid, even in so small pro- 
portion as meteoric water, comes into contact with calcareous 
silicates, they are decomposed the more readily the greater 
their percentage of lime. Now, as scapolite contains both 
lime and alkali, it might be inferred that both these decom- 
positions would take place together, but it seems that the 
process is more complicated. 
One of the substances most frequently present in the water 
of springs is protocarbonate of iron. The gas dissolved in 
such water almost always contains nitrogen in larger propor- 
tion than the atmosphere ; oxygen in much smaller propor- 
tion, although, according to the solubility of these gases, a 
contrary relation would obtain. This appears to indicate an 
abstraction of oxygen from the dissolved gas, and a conse- 
_ quent peroxidation.of the iron, which would account for the 
introduction of peroxide of iron into the scapolite. The car- 
bonic acid, liberated at the same time, would attack the lime 
and remove it in the state of bicarbonate. 
The substitution of potash for soda is far more difficult to 
account for. Supposing a mineral, containing silicate of 
