The Buffer Capacity of Sea Water

The titration of sea water in order to measure its excess of base, or what may be called its buffer capacity for acids, is not only of in terest from the standpoint of oceanography but also of practical value in the detection of acid wastes present in small quantities (Thompson and Bonnar, 1931). Several methods have been employed. Watten berg (1930) has described a method in which an excess of acid is added to the sea water, C02-free air is drawn through the boiling mixture un til all CO2 is removed, and then the water is back-titrated with stand ard barium hydroxide solution, using a mixture of brom cresol green and methyl red as indicator. Greenberg, Moberg, and Allen (1932) use a method of direct titration with standard acid, using methyl orange as indicator. Both of these methods, and others of which they are typical, require the use of rather elaborate precautions and of more or less cumbersome apparatus. Of recent methods, that of Thompson and Bonnar (1931) possesse