The Hydrogen-ion Concentration, etc., of Sea-Water. 



67 



whether HC1 or H 2 S0 4 was added, since HC1 is formed in sea-water 

 from H 2 S0 4 by dissociation of the large excess of chlorides. 



Dittmar found that the average excess base of sea-water was about 

 25. In a sample of Irish Channel water he found the excess base to be 

 23 and total C02 49.7 c.c. per liter. 



Tornoe found that average North Atlantic water contained 49.07 c.c. 

 of CC>2 per liter, and Petterson found that the maximum of all of his 

 samples contained 49.08 c.c. of C02 per liter (the water being drawn 

 from a depth of 55 meters). It may be noticed that Tornoe's average 

 is about the maximum, and probably the great majority of samples 

 were from the depths. 



10' 



IV 



20" 



25 



FIG. 24. Conversion table for finding the electric conductivity in 

 ten-thousandths of a reciprocal ohm from the salinity and 

 temperature. Each curve is for a different salinity. 



The samples collected by the Challenger during its cruise of three 

 and a half years were boiled by Buchanan and the CC>2 boiled off was 

 estimated ; then they were kept several years, during which time they 

 probably absorbed some CC>2 to replace part of that lost; then the 

 total 062 they contained was determined by Dittmar and added to 

 Buchanan's figures. Dole found about 45 c.c. of COz per liter in Tor- 

 tugas sea-water by a titration method. 



Dittmar showed that there is an average of 0.44 per cent more lime 

 in the water near the bottom (due to solution of shells) than at the 

 surface of the sea, which accounts for the increase in excess base with 

 depth. The tables of the Danish Ingolf Expedition show the following 



