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bearing on great geological problems that it seems indeed not superfluous 
to ascertain that quantity. At the same time apparently some infor- 
mation about the quantity of chlorine in river water is necessary, 
for in the sea sodium appears exclusively in chloride of sodium. 
When comparing the numerous analyses of river water now known, 
we observe that one fact is most salient. Of all the salts in solution, 
the carbonate of lime only, which is by far in the greatest quantity, 
is found in a somewhat constant proportion to the dissolving water. 
This salt, especially in the form of bicarbonate, the solubility of 
which is determined by the pressure of the carbonic acid of the 
atmosphere, is dissolved in it in about the same proportion as in 
pure water, which has been a long time in contact with a surplus 
of solid carbonate of lime and carbonic acid of the tension which 
it possesses in the atmosphere; evidently because river water has nearly 
always had plenty of opportunity to come in contact with limestone. 
Where in river water a surplus of carbonic acid is developed 
from the pollution with organic matter (as mostly is the case) the 
quantity of carbonate of lime increases somewhat. It remains on the 
contrary under the normal quantity in those cases, rare with large 
rivers, where the contact of the water with limestone was greatly 
limited or entirely wanting. It therefore may be accepted, that the 
water discharged by the rivers in the ocean may under the given 
atmospheric pressure of carbonic acid be considered as on an average 
saturated or a little more than saturated with carbonate of lime. 
Knowing the total annual discharge of water by the rivers, the 
annual supply of that salt to the ocean can be estimated. As for 
the other salts the case is quite different. Their solution remains far 
under the saturation point and they are found in greatly varying 
and often in very small quantities in the river water. As long as 
the quantity of them is only known from a limited number of 
rivers it is impossible to make anything approaching an accurate 
estimate of the amount which the ocean receives annually. This is 
especially the case with the sodium salts. Sodium belongs moreover 
to matters which it is difficult to determinate correctly in quantitive 
analysis, so that a number of analyses, especially such of former 
time, are not entirely to be relied upon. 
Repeated attempts of calculations like those of Jony had already 
been made from the quantity of chloride of sodium in the river water 
and the ocean water. According to MURRAY’s estimate the river water 
would contain per liter on an average 4.06 mgrm of it. MerLLARD 
READE had estimated the average quantity from the analyses of upland 
waters in England and Wales to be 16.6. QuENsTEDT and Dittmar had 
