60 ATOMIC WEIGHT DETERMINATIONS. 



of iron and indium were precipitated with ammonia, the 

 precipitate dissolved in acetic acid and impure indium sul- 

 phide reprecipitated. This operation was repeated, and the 

 last traces of iron were removed by partial precipitation 

 with ammonia. {Erdmaim's Journ. fur Prak. Cheyji., 92, 

 1864, 484.) 



C. Winkler : 107.754, (O = 16). 



Determined by decomposing the nitrate by heat, and 

 weighing the resulting oxide. The mean result of three 

 experiments was In = 35.918 for = 8, and assuming 

 the univalence of the metal. Extreme difference, 0.079. 

 Metallic indium was prepared by solution of the impure 

 sulphide in chlorhydric acid, precipitation of indium by 

 barium carbonate, solution in sulphuric acid, and precipita- 

 tion by ammonia of the oxide which was reduced by 

 hydrogen. [This indium seems to have contained iron. J 

 {Erdmami's Journ. far Prak. Chejii., 94-, 1865, 1.) 



C. Winkler : 113.439 (0 = 16). 



In two experiments the double chloride of gold and so- 

 dium was decomposed by pure indium, giving 37.73 and 

 37.80 for = 8, and assuming univalence for the metal. 

 In two experiments the nitrate was decomposed by heat, 

 giving In =: 37.845 and 37.879. In one experiment the 

 oxide was precipitated from nitric acid solution by ammonia. 

 This experiment gave In =: 37.811. The number taken is 

 the mean. The impure indium sulphide was puriiied as in 

 Winkler's former determination with barium carbonate, but 

 this process requires to be repeated several times. The re- 

 duction of the oxide was performed witli sodium, the excess 

 of which was removed from the regulus by cupellation in 

 soda. {Erdmann's Journ. far Prak. ^Chem., 102, 1867, 282.) 



E. Bunsen: 113.76 (0 = 16). 



Determined by converting metallic indium into oxide by 

 means of nitric acid and heat. He seems to regard the ex- 

 periment only as confirmatory of Winkler's. The metal 

 was the same which served for the determination of the 

 specific heat, and was carefully tested for all impurities. 

 {Poggend. Amial, I4I, 1870, 28.) 



