19^0 



Forcers J on Condition of Sea-icater 



371 



The oxygen content was determined by the Winkler method (Birge and 

 Jnday 1911). 



2. Experimental data 



During the progress of the work more than 500 samples were taken. 

 In the tables are given only those determinations which are character- 

 istic and can be subjected to comparison. The pH is used to express 

 tJie hydrogen-ion concentration of the sea-water or the hydroxvl-ion con- 

 centration, if you choose to call it so, instead of the Ch or Coh. The 

 pH is used by most workers on the hydrogen-ion concentration of sea- 

 water (Sorensen and Palitzsch 1910, Palitzsch 1911, McClendon 1916, 

 Henderson and Cohn 1916 and otliers). The error resulting from the 

 correcting of the so-called "salt error" to which Gaarder (1917) has called 

 attention is within that of the method used. The oxygen content is ex- 

 pressed in cc. per liter. Determinations were made only over a very limit- 

 ed area of the Sound and were confined mainly to the vicinitv of the Sta- 

 tion. All determinations on parenthetical dates M'cre made during the 

 summer of 1919 and all the numbers expressing the time of determina- 

 tions made in the forenoon are likewise in parentheses. An asterisk (*) 

 after the date in the tables indicates that it was clear weather when the de- 

 termination was made. The symbol (') indicates cloudy weather and the 

 double symbol (") indicates cloudy weather with rain. The symbol (o) 

 indicates that the tide was going out; (i), tide coming in; (h), high tide; 

 (1), low tide. 



3. HVDROGEN-ION CONCENTRATION AND OXYGEN CONTENT OF 

 SURFACE SEA-WATER 



On July 25 and 29, 1918, determinations were made of the surface 

 waters over a wide area of the Sound. By an examination of table 1 it is 

 seen that the pH varied from 7.77, station V, to 8.17, stations X and P. 



Table 1. The hi/drogen-ion concentration and o.ri/gen content of tlie 

 sea-water at a deptli of 30 centimeters helotc the surface in different 

 regions of the Sound. 



