422 E. J. ALLEN. 



reducing NagO to 100, the following figures, which give the relative 

 number of molecules or atoms : — 



NagO 100 



K2O 2130 



MgO 23104 



CaO 4499 



CO2 0-519 



503 12048 



CI 234-54 



which gives the following molecular proportions for the bases and radicals 

 separately : — 



Na 100-0 



K 213 



Mg 11-55 



Ca 2-25 



CO3 0-259 



504 6-024 



CI 117-27 



If we use solutions of salts containing a gram molecular weight per 

 Utre, since 1 c.c. of each solution contains the same number of molecules, 

 the relative number of c.cs., keeping the proportional amounts of the 

 bases, the CO 3 and the SO 4 as above, and making the remainder chlorine, 

 will be : — 



NaCl 99-58 



KCl 213 



CaClg 2-25 



MgClo 0-53 



MgS04 602 



NaaCOg 0-26 



Since these figures give the number of molecules of Na somewhat too 

 high, it was thought better to use 0"26 c.c. 01 sodium bicarbonate 

 (NaHCOs) instead of the normal carbonate, and this has been done 

 throughout. 



In making up artificial sea-waters it has been found most convenient 

 to prepare first of all gram molecular solutions of each of the above salts 

 and then to mix these in the proportions indicated. These molecular 

 solutions are easily prepared and the strengths of the chlorides compared 

 and corrected by titrating them with silver nitrate. 



