1915] Michael, ct al.: Hijdrographic Records of Scripps Iiistiiulioti 4-1 



4. RELIABILITY OF THE ASSUMPTION OF CONSTANT PROPORTION 

 OF THE SALTS IN SEA-WATER 



Reference has been fre(|uently made, in the preceding pages, to 

 Knudsen's .tables by means of which direct measurements of the 

 chlorine (halogen) content, specific gravity, or salinity of samples of 

 sea-water may be expressed in terms of each of the others. Except 

 as regards the relation between specific gravity and salinity, each of 

 which is a definite function of the other, the use of these tables de- 

 pends upon the reliability of the assumption that the halogen salts 

 bear a definite relation to the total salts dissolved in sea-water, as 

 illustrated by the formula: 



;S »/„„= 1.8050 CI "/„„+0.030 



Concerning this reliability Helland-Hansen (1911-12. p. 31) says: 

 "Although different analysers have found slightly different values for 

 the relative percentage of the salts in sea-water, it is nevertheless 

 proved that there is a constant proportion between the amount of 

 chlorine and the salinity or specific gravity, so that tables of the re- 

 spective values can be made out." Again (p. 32) he says: "The 

 specific gravity of the sea-water wholly depends upon the quantity 

 of dissolved salts. Now, as the .salinity has everywhere a uniform 

 composition, it is clear that the relations between the specific gravity 

 and the salinity or the amount of chlorine may be expressed in a gen- 

 eral formula with fixed constants." In spite of these positive state- 

 ments, however, he (p. 31) says: "In the waters of the Red Sea. for 

 instance, the relative amount of chlorine is a little below the normal; 

 further, there is generally a slight increase of the relative amount of 

 carbonates with increasing depth ; also, the formation of ice involves a 

 retention of proportionally more sulphates than chlorides in the ice. 

 so that the secreted brine contains a small excess of chlorides, and the 

 water around melting ice a corresponding excess of sulphates." 



"While Helland-Hansen (1911-12, p. 32) reaches the conclusion that 

 "these anomalies are insignificant . . . [and] . . . can only be detected 

 by extremely delicate analyses, and may be overlooked in practical 

 work," this is scarcely in harmony with the conclusion reached by 

 Nansen (1906). He made an extensive series of analyses of water 

 from the North Atlantic Ocean and the Barents Sea. having each 

 w-ater sample independently tested by two observers, one of whom 



