38 



The Sea-water and its Physical and Chemical Properties 



Table 9. The salts obtained from sea-water 

 (Calculated as 35 g of salts per kg) 



Salt 



weight in g/kg 

 sea-water 



Percentage of 

 total salts 



t Includes all the other salts present in trace amounts. 



inflow of fresh water and precipitation on the surface may have a low saHnity (8- 

 5%o) and at the inner ends mostly only brackish water with 1%^ or even lower. The 

 highest salinities are to be found, on the other hand, in the subtropical adjacent seas 

 with almost no inflow of fresh water, no precipitation and strong evaporation as, for 

 instance, in the Red Sea and in the Persian Gulf which at the inner ends have maximum 

 salinities of almost 40%o. 



While the salinity is always liable to show some variations the proportion of the 

 different ions in sea-water is remarkably constant. This constancy which is of con- 

 siderable oceanographic importance is only further confirmed by all carefully made 

 analyses. Accurate chemical analysis of the samples collected by the "Challenger" 

 Expedition from almost all parts, and depths of the ocean demonstrated this constant 

 proportion between the individual constituents and more recent investigations as 

 shown in Table 10 have led to the same results. 



Table 10. Analysis of the salt content of sea- 

 water (percentages) 

 (DiTTMAR, 1884; Makin 1898; Wheeler, 1910) 



The mean ratio Mg : CI is 0-0682 and for SO4 : CI the ratio is 0-1397. The most 

 recent analyses by Matthews, Thompson, and others, have given a value of 0-6802 

 (with limits of 0-6785 and 0-6814) for the first ratio and 0-1395 (with limits of 0-1387 

 and 0-1403) for the second. Using very accurate analyses calcium and bicarbonate 



