394 J. A. PHILLIPS ON MINERAL VEINS. 
In order to ascertain, approximately, to what extent the production 
of the large amount of heat absorbed by the water may be ascribed 
to oxidation of sulphur and iron, the Professor first calculates the 
quantity which would be developed by the oxidation of pyrites 
equivalent to the calcic sulphate in solution. But haying found 
that this amounts to only ;1, part of that required, he subsequently 
seeks another solution for the difficulty, and, without bringing for- 
ward any calculations in support of the hypothesis, attributes this 
enormous development of heat to the kaolinization of felspar con- 
tained in the adjacent rocks. 
If, however, we apply to the kaolinization of felspar for the heat- 
ing of water alone a somewhat similar line of reasoning to that 
adopted by Prof. Church regarding the oxidation of pyrites, we shall 
find that this source of heat is also utterly inadequate to produce the 
effects observed. 
The average proportion of alkalies contained in the rocks of the 
district is 6-40 per cent., while the mean of the published analyses 
gives 11:30 grains of alkalies in 58,373 grains (U.S. gallon) of 
mine-water. It consequently follows that the 4,200,000 tons of 
water annually pumped out of the workings must contain 813 tons 
of alkalies, and that, as these are present in the rocks in the pro- 
portion of 6:40 per cent., the felspar in 12,703 tons of rock must 
be annually kaolinized and the whole of the alkalies removed in 
solution. 
The amount of rock in which the felspar has been kaolinized 
being 12,703 tons, and the number of tons of water pumped out of 
: : 4,200,000 
the mines 4,200,000, it follows that 12,703 
of tons of water heated by each ton of altered rock. 
In order, therefore, that one ton of rock should be enabled to heat 
330 tons of water only 1° Fahr., and if the specific heat of these rocks 
be taken at -1477, which is that of blast-furnace slags, it would re- 
quire to be heated by the kaolinization of its felspar to a temperature 
above that of molten gold. Consequently to raise the water 85°, 
or to a temperature of 135°, at which it issues, the kaolinization 
of the felspar in each ton of rock would require to elevate it to 
an extent we are unable to estimate, since there are no means of 
ascertaining the specific heat of bodies at such enormously high 
temperatures. 
It is therefore evident that the kaolinization of felspar is no 
more than the oxidation of pyrites an adequate cause to account 
for the heat of the Comstock lode; and in the present state of our 
knowledge we cannot regard this phenomenon otherwise than as 
being a last trace of volcanic activity. Prof. Church adduces the 
high temperature of the waters of Steamboat Springs as a proof that 
the rocks of this region are capable of producing sufficient heat to 
raise large quantities of water to the boiling-point; but these springs 
give rise to an evolution of sulphuretted hydrogen and to a depo- 
sition of sulphur, which cannot be results of the decomposition of 
=330 is the number 
