472 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



The ammonium salt. IrCla.SNH^Cl, gave the subjoined data : 



Mean, 42.003, ± .0094 



Hence Ir= 193.078. 



To sum up, the ratios available for iridium arc these: 



(1). Per cent. Ir in AmJrCl„, 43.732. -t .0035 



(2). Per cent. Ir in KJrCln, 39.880, ± .0015 



(3). Per cent. KCl in KJrCle. 30.820, ± .0037 



(4). Per cent. 4C1 in K,IrCl„, 29.291, ± .0024 



(5). Per cent. Ir in AnialrClo, 42.003, ± .0094 



(G). Ir :3KCI:: 100: 115.848, ± .0583 



To reduce tliese ratios we have — 



Hence, 



From ratio 3 Ir = 192.881, ± .0189 



" 2 192.999, ± .0084 



" 6 193.078, ± .0971 



" 4 193.274. ± .0416 



" 5 193.277, ± .0534 



" 1 193.395, ± .0196 



General mean, Ir = 193.047. ± .0070 



In a pve]iminar\r note Archibald' states that from analyses of the 

 salt K.,TrClf. he has obtained the value Ir = 192.90. His investigation 

 is still in progress, and no detail'^ have yet been published. 



' Chetn. News, 100, 150. 1909. Paper read before the British .Association for the .Vdvancfment 

 of Science. 



