1920 



Powers; on Condition of Sea-zvater 



377 



Table 5. The hydrogen-ion concentration and the oxygen content 

 of the surface sea-7cater at station A. 



Date 



— 77T3^ 



7/16" 



7/16" 



7/31* 



7/31* 



(6/30*) 



(7/1*) 



(7/7*) 



(7/10*) 



(7/11*) 



(7/12*) 



(7/12*) 



(7/12*) 



(7/14*) 



(7/17*) 



(7/21*) 



(7/21*) 



(7/22*) 



(7/23') 



(7/23') 



(7/23') 



(7/23') 



(7/23') 



Time 



4:15 



3:55 



4:20 



4:45 



5:00 



3:00 



ni:45) 



8:07 



3:15 



7 :25 



(9:35) 



7:20 



9:00 



2:00 



3:20 



.9:10) 



:!:20 



3:10 



r5:50) 



(6:15) 



(7:00) 



(10:10) 



2:50 



Tide 



Depth 



in 



em. 



Temperature 

 Centigrade 



10 

 10 



500 

 10 



500 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 



11.9° 



10° 



9.9° 

 10.4° 

 12.2° 



11.6° 



12.7° 



11.9° 



12.4° 



1S.5° 



13.3° 



13° 



13.5° 



12.8° 



12.8° 



12.8° 



of the surface water at station A was determined at intervals from 5 :50 

 A. M. until 2:50 P. M. The pH rose continuously thruout the day 

 regardless of the stage of the tide. This was doubtless due to the effect 

 of light upon the vegetation. At station D, on June 26. 1919, at 4:25 P. M., 

 when the tide was coming in the pH was 7.77 and at 7:45 P. M. when 

 the tide was going out the pH was 7.82i with two tenths of a degree lower 

 temperature. On July 12, 1919, station A, all determinations were made 

 when the tide was going out. The lowest tide, 9:35 A. M., showed the 

 highest pH, 7.90; the next lowest tide, 9:00 P. M., gave the next highest 

 pH, 7.87. Station D, July 9, 1919, showed no difference between low 

 and high tide. These are isolated cases and too much confidence cannot 

 be placed in them as sometimes samples taken only a few feet apart on 

 the surface of the water showed a difference in the pH with practically 

 the same temperature. (See determinations made at station Q. July 9, 

 1919, table 3.) On June 25, 1919, four samples were taken between 

 station D and Brown] Island (station B) within a radius of 50 meters and 

 with only fifty minutes elapsing between the taking of the first and last 

 sample. The following are tlie determinations with the appended notes: 

 2:30 P. M,, cloud}^ and drizzling rain, just southwest of lirown Island, 

 pH 7.52, 9.7° C; 2:50 P. M., just south of last point, no oil on surface, 

 but few drifting Ulva. i)H 7.67, 9.6° C. ; 3:05 P. M.. just south of second 

 in drift of algae and oil, pH 7.55, 9.6° C; 3:20 P. M., just south of 

 third in clear water, pH 7.55, 9.5° C. 



