i6 
bulletin 82 
§ 27. This fact is not surprising except when we attempt to 
express the amounts removed in figures, for everyone conversant 
with the rocks of the country knows that the predominant minerals 
are felspar, quartz, and mica, of which the quartz is the least easily 
attacked by water. The experiment given shows that it is a fact 
that this is the source of the silica, potash, lime, etc., contained 
in the water. 
■§ 28. The presence of sulfuric acid and chlorin in these 
waters was not easily explainable. In the jura-triassic strata we 
have an abundance of gypsum from which calcic sulphate might be 
derived, and in fact this was the source from which I considered much 
of this salt to have been derived; but this could not possibly be the 
case where the sample was taken before it had come in contact 
with this formation, or could have received water which had done 
so. The analysis of the portion of felspar dissolved by water with 
the aid of carbonic acid shows a surprising amount of each of these 
constituents—sulfuric acid, over nine per cent., and of chlorin more 
than three per cent. The carbon dioxid and even the air drawn 
through the solution was well washed to avoid the introduction of 
extraneous substances. The v/ater used was freshly distilled, leav¬ 
ing no residue upon evaporation, and failing to show a trace of 
chlorin. The felspar had been tested for sulfuric acid, and showed 
a few hundredths of one per cent.; but it was not tested directly for 
chlorin. The quantity found in its aqueous extract, however, 
leaves no doubt of its presence. This mineral, felspar, accordingly 
may furnish the sulfuric acid and chlorin found in our mountain 
waters, as well as the total solids in general. 
§ 29. There is still stronger evidence, if there were need of it, 
and that is the presence of strontia and lithia in the water. In 
Bulletin No. 35, in a note upon the ash of alfalfa, I called attention 
to the fact that strontia was always present, but lithia was not de¬ 
tected in any single instance. Again in Bulletin No. 72 I called 
attention to the fact that lithia was found to be generally present 
in the ground waters which I had examined. I do not think that 
I have tested a single sample of ground water (and I have tested 
many within the past five years), that failed to show the presence 
of lithia. The same may be said of the Poudre water. I have also 
found it present in the waters of the St. Yrain, the Boulder, Clear 
Creek, and in the water of the Running Lode mine taken at a depth 
of 825 feet; also in the waters of the South Platte and the Arkan¬ 
sas. Its presence in the waters of the South Platte is not so signifi¬ 
cant, for there are several springs discharging into this river which 
I know carry some lithia, but the relative volume of these springs 
is small, and I am convinced that the lithia found indicates its 
more general occurrence in the waters of the Platte, and the same 
may be said of those of the Arkansas, for I doubt whether the small 
