42 



ATOMIC WEIGHTS OF SODIUM AND CHLORINE. 



Corrected excess weight Gooch crucible (dried at 150 ) over Grams. 



counterpoise 0.21709 



Corrected excess weight crucible and AgCl (dried at 150 ) 



over counterpoise 13.87382 



Weight of silver chloride in air 1365673 



"Vacuum correction _|_ 0.00100 



Weight of unfused AgCl in vacuum 13-65773 



The mother liquors and wash water were passed through a small 

 filter, which was ignited in a small porcelain crucible. 



Grams. 



Corrected excess porcelain crucible over counterpoise 0.42525 



Corrected excess, plus residue and ash 0.42535 



Residue and ash. 

 Ash 



0.000 10 

 0.0000 1 



Residue, asbestos shreds 0.00009 



Loss of chlorine during ignition (see page 39) +0.00001 



Total residue. 



0.000 10 



A large portion of the silver chloride, 10.50 grams, was fused in a 

 small approximately counterpoised crucible weighing about 8 grams. 



Grams. 



Correoted excess crucible, plus AgCl, over counterpoise* 10.64846 



After fusion, corrected excess over counterpoise 10.64769 



Loss of 10.50 gm. AgCl on fusion 



13.66 



.00077 



Hence loss of total AgCl 



10.50 



X 0.00077=0.00100 



The nephelometer revealed no chloride in the mother liquor and 

 first five washings ; the correction of +0.07 milligram was applied for 

 this solubility even in the presence of the excess of silver nitrate. 



Washings No. 6 and 7, volume 0.220 liter in all, were found 

 to have a trace of chloride, and its amount was estimated by the 

 nephelometer, making comparison with two different standard tubes. 



The factor for converting 1 milliliter of standard solution in a 

 nephelometer tube into silver chloride per liter was 0.047. 



*In this case the counterpoise contained no argentic chloride, but in the 

 most careful experiments the counterpoise contained as much of this salt as the 

 test crucible. 



