118 CH SMY RECS 
pared with the composition of the granite, and this is accentuated 
by the figures for relative solubilities (XXI and XXIJ). 
Even the groups have been changed, and magnesia has gone 
far ahead, not only of soda, but also of lime, becoming conspicu- 
ously the most soluble constituent. The remaining four con- 
stituents have relative solubilities not widely different from the 
normal, and if multiplied by five give soda 82, potash to, silica 5, 
and sesquioxides 0.5. Such divergences from the average results 
are only what is to be expected, indicating, as they do, how local 
conditions control the action of drainage waters. 
Headden has laid stress upon the high silica content of this 
water, in which respect it is remarkable, and not only is the content 
of silica high, but the relative solubility is also high, as compared 
with soda, potash and the sesquioxides. But, from the present 
point of view, the striking feature is not the silica content but 
the relatively great lime and magnesia content, implying high 
relative solubilities. 
As in the case of soda in the sediments, but to a much more 
pronounced degree, low content of lime and magnesia is accompa- 
nied by high relative solubility, and it seems probable that this 
relation is a general one. 
This relation is particularly suggestive in connection with the 
problem of ore deposits, where it is always so difficult to account 
for the concentration, into workable bodies, of minute quantities of 
disseminated metals. If the 0.74 per cent of lime and 0.07 per 
cent of magnesia can, by the differential solvent power of drainage 
waters, be concentrated to 31.12 per cent and 7.22 per cent, respec- 
tively, of the abundant oxides in the water, it is safe to assume 
that the much less abundant metals of rocks may undergo an 
analogous and, perhaps, even greater, concentration, by under- 
ground waters, either meteoric or magmatic. Perhaps this relation 
becomes more apparent if the relative solubilities of lime and mag- 
nesia are multiplied by five, as the others were to bring them up to 
the normal numbers. In this case the solubility of lime is 500 and 
that of magnesia is 1,222. 
Of course, in the ore deposit problem, it is of vital importance 
to know what compounds of the metals are involved, but, in spite 
