NITROGEN. 61 



But neither of these series can for a moment compare with that of 

 Stas. * He used from 12.5 to 80 grammes of silver in each experiment^ 

 reduced his weighings to a vacuum standard, and adopted a great variety 

 of precautions to insure accuracy. He found for every 100 parts of silver 

 the following quantities of NH 4 C1 : 



V 



49.600 



49.599 



49-597 



49.598 



49-597 



49-593 



49-597 



49-5974 



49.602 



49-597 

 49598 

 49-592 



Mean, 49-5973, .0005 



In this work, as with the similar ratios for potassium and sodium 

 chloride, the solubility of silver chloride was not guarded against so fully 

 as is needful. Accordingly Stas published a new series of determina- 

 tions in 1882,f carefully checked in this particular, with the subjoined 

 values for the ratio : 



49.60001 

 49-59999 

 49-599 

 49.600 



49.597 

 Mean, 49-S99 2 , .00039 



Combining all four series, we have 



Pelouze 49-5365, =b .013 



Marignac 49-5 2 3> -OQ55 



Stas, early series 49'5973, d= .0005 



Stas, later " 49.5992, .00039 



General mean 49-5983, .00031 



In the paper last cited Stas also gives a similar series of determinations 

 for the ratio Ag : NH 4 Br : : 100 : x. The results are as follows, with re- 

 duction to vacuum : 



* Aronstein's translation, pp. 56-58. 

 fMemoires Acad. Roy. de Beige., 43. 1882. 



