612 Me, (Co (CLAAMIBIEIRILION 
(2) that which constitutes the second equivalent of the bicar- 
bonates—essentially the bicarbonate of lime. The estimate 
does not include the carbon dioxide which is united with the 
basic oxides to form monocarbonates and which may be said to 
be fixed. To put the matter in another form, only that carbon 
dioxide enters into the computation which separates from the 
sea water upon evaporation. 
According to the old method of interpreting analyses the car- 
bonate of lime present in sea water should all be bicarbonate. 
It appears, however, from Dittmar’s investigations that the 
’’ carbon: dioxide in the ocean is only about 
one-half what would be required if all the carbonate of lime 
amount of ‘‘loose 
(interpreted under the old system) were bicarbonate. The 
proportions are about as though the lime existed in the state 
of a sesquicarbonate—a compound of doubtful existence. 
Under modern methods of interpretation this lower proportion 
is theoretically explicable, for each of the basic oxides in the 
sea water enters transiently into combination with each of the 
acids, and a larger proportion of monocarbonates is thus con- 
sistent with solubility, and, in addition, free ions of both oxides 
and acids are concurrently present. Under this system of inter- 
pretation the proportion of carbon dioxide necessary to maintain 
the lime in a state of solution is reduced. In accordance with 
these direct determinations it will be assumed in the discussion 
that the ‘“‘loose”’ equivalent of carbon dioxide is only half the 
amount necessary to render the carbonate of lime a bicarbonate. 
It is by no means certain that under the conditions of an atmos- 
phere rich in carbon dioxide the amount would not reach the 
full second equivalent required by the old chemical philosophy, 
but the more conservative basis serves equally well the purposes 
of this discussion.* 
Data are lacking for more than a very rude approximation 
to the amount of free carbon dioxide held in simple solution in 
the ocean, but such data as are available seem to indicate that it 
t The elaborate investigations of Treadwell and Renter (Zeitsch. Anorg. XVII, 
p- 170) indicate that the lime is essentially bicarbonate so far as it is carbonate at all. 
