154 A. L. Day and R. B. Sosman — 



The portion insoluble in KHS0 4 was freed from silica 

 (which came from the dish) by HC1 + HF, ignited, and weighed. 

 Ir + [Ru] = 1-9 mg. = 0-008 per cent. When fused with 

 K a C0 3 4- I£N"O a , some blue insoluble Ir0 3 was formed, but the 

 fusion showed no yellow color, and in view of the minute quan- 

 tity of material, it was not thought worth while to search more 

 carefully for ruthenium. 



The final precipitate of palladium acetylide was changed to 

 chloride, diluted, and saturated with S0 2 for gold, but none 

 appeared. 



Nothing else was found in the metal except a trace of cop- 

 per. The iron found earlier had to be reprecipitated several 

 times from chloride solution by ammonia to get rid of palla- 

 dium. The precipitate was finally transformed into sulphate 

 and determined ■ volumetrically. — Fe = 2'6 mg.='010 per cent. 



Analysis of Palladium. 



Au._ _ none 



Ru none 



Rh._ .„ none 



Pt '00l</o 



Ir -008^ 



Cu trace 



Zn doubtful trace 



Fe -.. -010$ 



•025$ 

 Kahlhaurris Electrolytic Nickel. 



Two 50 gram portions were dissolved separately in measured 

 quantities of nitric acid and then carried to white fumes with 

 excess of sulphuric acid. Both portions were then dissolved 

 in water and filtered. There was a small dark residue which 

 was washed thoroughly and extracted with aqua regia, leaving 

 a little silica from the dish. The yellow chloride obtained 

 was freed from nitric acid, saturated with S0 2 and left to stand. 

 No gold. Changed to chloride again and tested with caustic 

 soda and H 2 2 . Still no gold. Acidified and reprecipitated 

 with NH 4 C1, a characteristic yellow precipitate was obtained. 

 Confirmed by dissolving the chlor-platinate in hot water and 

 precipitating by hydrogen. Pt = 2'3 mg. = 0*0023 per cent. 

 The main solution was then precipitated by H 2 S (v — 2 1.). 

 The small black precipitate obtained was worked over for gold 

 and platinum with the above. 



Other heavy metals were tested for in the ordinary way. 

 0-2 mg. PbS0 4 = about 0-1 mg. Pb. Cu=52'3 mg. = 0-0523 

 per cent. 



Ammonium Sidphide Group. — The voluminous solution 

 was now freed from hydrogen sulphide by evaporation, some 



