THE 
mewRNAL OF GEOLOGY 
FEBROARY-MARCH, 10913 
fae RELATIVE SOLUBILITIES OF: THE CHEMICAL 
i CONSTITUENTS OF ROCKS 
C) Ho SMYTH: Jr: 
Princeton University 
Several years ago, while making an estimate of the rate of 
chemical denudation, which, from skepticism in regard to the 
trustworthiness of the available data, was never offered for publi- 
cation, the writer was impressed with the desirability of deter- 
mining, so far as might be possible, the average relative rates at 
which the predominant chemical constituents of rocks were taken 
into solution in drainage waters. So far as could be learned at 
the time, the problem had never been definitely formulated on a 
quantitative basis, nor its solution in numerical terms attempted. 
The writer’s aim was to obtain definite numbers which should 
express the relative rates at which the common oxides are dis- 
solved by natural waters, using the oxides in the ordinary con- 
ventional sense in which they are considered as rock components. 
To be more explicit, the actual minerals, of which rocks are made 
up, were not considered at all but merely the ultimate chemical 
composition of rocks, expressed in terms of oxides. While the 
method pursued gave results suggesting interesting possibilities, 
it was felt that, as in the case of the problem of chemical denudation, 
the data available were not sufficiently trustworthy to warrant 
publication. At present, however, more reliable data are at hand 
Vol. XXI, No. 2 105 
