270 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



.5574 grm. In gave .6817 grra. In^Oa. 

 .6661 " .8144 



.5011 " .6126 



Hence, in mean, In = 107.7^6; a result even lower than the values al- 

 ready cited. 



In a later paper by Winkler ' better results were obtained. Two 

 methods were employed. First, metallic indium was placed in a solu- 

 tion of pure, neutral, sodio-auric chloride, and the amount of gold pre- 

 cipitated was weighed. I give the weighings and, in a third column, 

 the amount of indium proportional to 100 parts of gold : 



In. Au. Ratio. 



.4471 grm. .8205 grm. 57.782 



.8445 " 1.4596 " 57.858 



Mean, 57.820 



Hence, if Au = 197.269, In =114.06. 



Winkler also repeated his earlier process, converting indium into 

 oxide by solution in nitric acid and ignition of the residue. An addi- 

 tional experiment, the third as given below, was made after the method 

 of Eeich and Eichter. The third column gives the percentage of In in 

 In.O;, : 



1.124 grm. In gave 1.3616 grm. In^Os. 82.550 per cent. 



1.015 " 1.2291 " 82.581 



.637ff " .7725 " 82.537 



These figures were confirmed by a single experiment of Bunsen's,' 

 published simultaneously with the specific heat determinations which 

 showed that the oxide of indium was lUoOj, and not InO, as had been 

 previously supposed : 



1.0592 grm. In gave 1.2825 grm. In^Os. 82.589 per cent. 



For convenience we may add this figure in with Winkler's series, which 

 gives a mean percentage of In in In^Og of 82.564. Hence In = 113.646. 



Recent investigations have shown that all of the foregoing deter- 

 minations are untrustworthy, and that they give values for the atomic 

 weight of indium which are too low. Thiel ' carefully investigated the 

 properties of indium oxide, and found it to be quite unsuited to atomic 



' Joum. prakt. Chem., 102, 282. 



- Poggend. Annal., 141, 28. 



' Zeitsch. anorg. Chem., 40, 280. 1904. Preliminary in Vol. 39, 119, and Ber., 37, 175. 



