THURAS: RECORDING SEA-WATER SALINITY 



683 



for different solutions of the same concentration. Previous tests 

 on the two cells in a bridge circuit also indicate that for small dif- 

 ferences in concentration (salinity of 35 to salinity of 32) there 

 was no appreciable change in resistance with frequency. The 

 sea-water conductivity measurements have therefore been made 

 with the assumption that the resistance change with frequency 

 is the same for 1 /lO N, KCl as it is for sea water. 



Fig. 3. Electrolytic cells. Mounted in the hard rubber cover of the bath. 



The sea water for conductivity measurements was collected 

 by the U. S. S. Androscoggin on April 9, 1918, in Latitude 30°-4'N 

 and Longitude Q7°-10'W. This water had a high salinity and 

 the more dilute samples were prepared from it by adding dis- 

 tilled water. The one sample of a higher salinity was prepared 

 by carefullj^ distilling sea water. The distillate was measured for 

 conductivity and the low conductivity obtained showed that 

 no chemicals in the sea water were given off. 



