24 



Papers from the Department of Marine Biology. 



will be explained later. It is more convenient to abbreviate the names 

 of positive and negative ions thus : H* = hydrogen ion, Cl' = chlorine ion. 

 Since concentrations per liter and per kilogram may be readily 

 converted one into the other if the density of the solution is known, 

 charts for computing the density of sea-water are given in figures 1 



30 



Salinity 

 35 



10' 



17 



18 19 20 21 



Grams Cl per kilogram sea-water 



22 



FIG. 1. Conversion table for finding the density of sea-water (at any tem- 

 perature), referred to distilled water at 4 from the salinity or the Cl in 

 grains per kilogram. Each diagonal is for indicated temperature only. 



and 2. This gives the actual density in question, as it is obviously 

 insufficient merely to know the specific gravity at some standard 

 temperature. The direct determination of the specific gravity by 

 means of a floating hydrometer is often vitiated by large experimental 

 errors, and many of these instruments are made for a standard temper- 



