128 ATOMIC WEIGHT DETERMINATIONS. 



tic tungstate was decomposed with nitric acid and titrated 

 with sodium chloride or decomposed with hot sodium 

 chloride solution, the argentic chloride being weighed. 

 Five experiments gave a mean of 91.915 for W ; extreme 

 difierence, 0.13. The argentic tungstate was prepared by 

 the precipitation of sodium tungstate with argentic nitrate, 

 thorough washing and drying in yellow light. The per- 

 manganate solution was prepared according to Mohr and 

 tested with ammonio-ferrous sulphate. Fe = 28, Ag := 

 108. {Poggend. Ami., 130, 1867, 30.) 



H. E. KoscoE : 184.04 (0 = 16). 



Determined by reducing tungstic acid in a current of 

 hydrogen, by reoxidizing the metal, and by reducing the 

 chloride in a current of hydrogen, the chlorhydric acid 

 being condensed and estimated as argentic chloride. In 

 the experiments on the acid, that compound was reduced, 

 and reoxidized three times with almost identical results. 

 The mean of the second and third reductions of the same 

 sample gave W = 183.84. In the experiments on the 

 chloride, the chlorine and the tungsten were each deter- 

 mined, and gave a mean of 184.25 for CI = 35.5. The 

 tungstic acid was prepared by the decomposition of the 

 chloride, washing and heating to redness in a platinum 

 vessel. It was canary yellow. The chloride was prepared 

 from pure tungsten. [Liebig's Ann., 163, 1872, 366.) 



URANIUM. 



No certainty exists as to the relation between the equiva- 

 lent and the atomic weight of uranium. The latter is com- 

 monly accepted as about 120. Mendelejeft" gives grounds 

 for supposing it to be 240, {Liebig's Ann., S. 8, 1871, 178,) 

 and L. Meyer regards it as probably 180, a value which 

 accords well with the specific heat of the black oxide as 

 observed by Regnault. [Gmelin- Kraut, I. c.) For the pur- 

 poses of this paper it seems best to retain the customary 

 value. 



J. A. Arfvedson : 128.6 (O = 16). 

 Determined by experiments on the reduction of uranoso- 



