RICHARDS AND ROGERS. — ATOMIC WEIGHT OF ZINC. 179 



In no one of the other determinations were both silver and argentic 

 bromide determined, hence the others were simpler in execution, 

 although essentially the same in principle. The end point in analy- 

 sis 17 was probably not determined more nearly than two tenths 

 of a milligram, while that in analysis 19 was determined by the 

 nephelometer * much more accurately even than in the detailed deter- 

 mination. Indeed this value was so accurate that the hundredths of a 

 milligram may have some significance, although the weights taken 

 were so large. The data of all these final determinations are given 

 below. 



FINAL DETERMINATIONS. 



The Ratio of Zincic Bromide to Silver. 



The Ratio of Zincic Bromide to Argentic Bromide. 



From the first ratio, if 0= 16 

 From the second ratio, if = 16 

 Average, if = 1 6 



If = 15.96 

 If 0=15.88 



Zn = 65 402 

 Zn = 65.406 

 Zn = 65.404 



Zn = 65.240 

 Zn = 64.912 



* These Proceedings, XXX. 385. 



