232 GOLD. 



All = 197. GOLD. 



Potassium Bromo-Aurate, Ka Br4 Au = 556. 



The compound was reduced, and the gold filtered off and 

 weighed; this is objectionable. 



The corresponding atomic ratio is 



Au : Ka Br-Aurate== 197 : 556 = 0.35 432. Change n high. 

 Kriiss, 1886, made nine determinations, the best extant for 

 gold. 



Reduction was effected by SO2 in Nos. i, 2, 5, 6, 7; by 

 H (dry way) in 3, 4, 8, 9. The mean of the first is 30 high, 

 of the latter, 28 high; hence, no great difference. 



The mean of all nine determinations is 29 high, corres- 

 ponding to 0.26 on the atomic weight. 



But we obtain quite valuable indications by collecting 



the results according to the amount of substance used, which 



substance being dried over phosphoric oxide without heat, 



was the most unobjectionable of all employed up to date. 



Aurate, ab't 10.5 gr. 3 Det.,o.35 474 42 high. 



7.3 3 Det., 457 25 high. 



5-4 " 3 D et., 453 21 high. 



Extremes: 7.0 gr. Min. ratio, 440 8 high. 



10.6 " Max. ratio, 476 44 high. 



Total range : 36. 



Here we notice a gradual approach to the atomic ratio as 

 the amount of substance diminishes; the lowest individual 

 result is obtained with a medium amount of substance, while 

 the highest was obtained by the second largest amount used. 



It is this very marked effect of the amount, causing a 

 gradual approach to the atomic ratio as the amount of sub- 

 stance is reduced, which gives this work of Kriiss its value. 

 It plainly points the way, how to proceed in a really serious 

 redetermination. It is, de facto, in accord with my limit 

 method. 



Since o.i gives the ratio n high, we have for 

 substance, 10.5 7.3 5.4 grammes. 



Au = 197.38 197.23 197.19 



The two extreme ratios give : 



Max. 197.40. Min. 197.07. 



