taken to avoid light exposure. The amount of excess AgXOs adhering 

 to the precipitate of Ag(l was found neghgible except in early trials 

 when a large excess was present. The overall precision for the 

 replicate analyses shown in table 1 is less than ±0.002°/oo in chlorinity 

 and the accuracy is safely estimated the same magnitude as will be 

 seen by exammation of the pure silver analyses. 



The ratios giving the relative strength of all solutions were deter- 

 mined by multiple analyses with good precision: 



1. Strength of the weak titration li([uids in relation to one another: 



ml.ofXH,SCN ^,,o„3 (^0,00,) 



ml. of AgX03(weak) 



(mean of 5 determinations) 



2. .Strength of weak titration litjuids by comparison to AgXOa 

 strong: 



AgXO3(strong) ^0.09G7 gm in air/miUiliter 

 ml. XH4SCX (±0.0001) 



(mean of 8 determinations) 



o. Strength of AgX'O.s strong by comparison with P-2S X'ormal 

 Water: 



P— 28 



-T-^.^=0.94347(± 0.00008) 

 AgA W3 



(mean of (i determiiuitions) 



Absolute "Atomic iveight silrer" technique: 



Based on the new definition of chlorinity: 



"The number giving the chloi-inity in grams per kilogram of a sea- 

 water sample is identical with the numljer giving the mass in grams 

 of "atomic weight silver" just necessary to precipitate the halogens 

 in 0.o28o2;^3 kilogram of the sea-water sample." 



Cl°/oo = 0.3285233 gm silver necessary 



The values for P-28 X'ormal Water and International Ice Patrol 

 sample Xo. 1 waters were determined using pure U.S. Mint Silver. 

 The last such analysis of X'ormal water was made in 1938 by O. 

 Honigschmid * reported for Urnormal 1937. 



About 75 gms. of sample were weighed in a 125 nd. Erlenmeyer. 

 Foi- each known mass of sample a very slight (ca. 10 mg.) excess of 

 ])urc silver was weighed. The silver was in the form of small pellets. 

 The pellets (ca. l-)! mm. in diameter) were cleaned with acetone, 

 l)oile(l and soaked in Id l)aielies of conductivitv water, examined 



77 



