66 Papers from the Department of Marine Biology. 



increases so rapidly. Rise in temperature decreases the viscosity of 

 water and in this way increases the conductivity. It is probable that 

 ionization is increased slowly by dilution and also by rise in temperature 

 of sea-water. 



THE EXCESS BASE AND THE C0 2 CONTENT OF SEA-WATER. 



Tornoe observed that sea-water is alkaline to litmus or rosolic acid. 

 He added a known excess of normal H^SCX to a liter of sea-water, 

 boiled off the COz and caught it in a known solution of Ba(OH)2 for 

 determining the total C0 2 and titrated the sea-water back with CO-r 



Conductivity=10 s (A) 

 1234567 



40 



FIG. 23. Conversion table for finding the electric conduc- 

 tivity of sea-water in hundredths of reciprocal ohms 

 from the salinity and temperature, based on deter- 

 minations by Ruppin. Each curve is for a different 

 temperature. 



free alkali, using phenolphthalein as indicator. He found the excess 

 base to be 24 (in our terminology) as a mean value for the parts 

 investigated of the North Atlantic. In titrating with phenolphthalein, 

 the silicates and part of the borates are decomposed (i. e., not re-formed 

 when titrating back), but part of the borates and phosphates act as 

 neutral salts, and we found that the result is about 5 per cent lower 

 than with our method, in which boric and a small amount of phosphoric 

 acid do not affect the result. On the other hand, the results may be too 

 high if too great excess of acid is added or if it is boiled too long, since 

 HC1 gas is liable to pass out with the steam. It makes little difference 



