614 
OCEANOGRAPHY: J. F. McCLENDON 
in sea water, i.e., the sum of the base equivalents is greater than the 
sum of acid equivalents. Since calcium is added to or taken from sea 
water in the form of CaCOs, and change in the calcium content causes 
an equivalent change in the excess base or alkahne reserve, as it is 
called by chemists. The alkahne reserve may be titrated while boiling 
the sea water to eliminate CO2. The exact value of the titration de- 
pends on the indicator used and the exact color of the indicator that is 
taken as the end point, hence only those titrations done in the same 
manner can be strictly compared. The titrations, used for the present 
paper were made by adding di-brom-o-cresol-sulphone-phthalein to 100 
cc. of sea water in a flask of resistance glass and titrating with 0.01 N 
HCl, while boiling, until the purple color changed to yellow and did not 
become purple again after boiling for 5 minutes longer. The sides of 
the flask must not be allowed to dry as this would cause HCl to escape 
from the chlorides, due to the action of Magnesium. The results per 
liter were recorded and some titrations were made at 20° and others at 
30°, but the errors due to change in volume of the sea water is within 
the limits of accuracy of the method. If the sea water is diluted with 
rain water, the alkahne reserve will be lowered, but this error may be 
compensated by dividing by the chlorine content (grams chlorine per 
kilogram sea water). In other words: a change in the quotient of the 
alkahne reserve by the chlorine per cent indicates a gain or loss of 
CaCOs. 
ALK.O-INE RE- 
SERVE 
ci 7oo 
■0,000 
Sea water from San Diego, Cal 
0.00235 
18.7 
1.257 
Sea water from Woods Hole, Mass 
0.00240 
17.7 
1.356 
Gulf Stream, off Miami, Fla 
0.00250 
19.9 
1.257 
Gulf Stream, off Tortugas, Fla 
0.00250 
19.9 
1.257 
Average, Tortugas, June and July 
0.00247 
20.0 
1.235 
0.00237 
20.0 
1.185 
The above table indicates that some CaCOs has been removed from 
Tortugas sea water, as compared with other sea water, and to a greater 
extent from Key West sea water. In other words, the precipitation 
observed by Vaughan is not due to a greater amount of calcium in 
Tortugas or Key West sea water but to local conditions which cause the 
precipitate to form. 
According to the law of mass action, in a saturated solution of CaCOs 
in sea water at constant temperature, salinity, etc., 
[Ca'*] X [CO3"] = a constant. 
