THALLIUM. 119 



a mean of 204; extreme difference 1.2. An experiment on 

 the precipitation of the sulphate with harium nitrate gave 

 204.3. [The atom'ic weights used were probably those ac- 

 cepted by Dumas.] The salts were purified by recrystalli- 

 zation. [Annal. de Chim.. et de Phi/s., (3,) 67, 1863, 411.) 



W. Crookes : 202.96 (O = 16). 



These determinations were made from the sulphate, which 

 was prepared with great care. By decomposing the sulphate 

 with potassic iodide and weighing the thallic iodide formed, 

 the atomic weight was found at 202.73; by precipitation 

 with barium nitrate, 203.55 ; with chlorhydric acid and 

 alcohol, thallic chloride being weighed, 201.85 ; from the 

 amount of sulphate produced from a known weight of metal, 

 203.1 ; by precipitation with platinum chloride, 203.56. The 

 values taken for CI, I, etc., are not given ; [they were prob- 

 ably those accepted by Dumas.] [Erdmaiw's Journ. filr 

 Prak. Chem., 92, 1864, 277 ; Chem. News.) 



H. Werther : 204 (0 = 16). 



In five experiments Werther decomposed thallic iodide 

 with potassic hydrate and zinc, both perfectly pure, and 

 precipitated the iodine with silver. The mean result of 

 these experiments was Tl = 204.4 ; extreme difterence 1.7. 

 [The value assumed for I is not stated. One experiment, 

 which gave exactly 204, according to Werther, recalculated 

 for Ag = 107.93 ; I = 126.85 gives Tl = 203.63.] Three 

 experiments were made by decomposing the iodide with 

 aramoniacal solution of argentic nitrate and weighing the 

 argentic iodide formed. These determinations gave Tl = 

 203.47; extreme difference 0.3. The preparation of the 

 iodide is not given. [Erdmann's Journ. filr Prak. Chem., 92^ 

 1864, 136.) 



M. Hebberling : 203.94 (O = 16). 



Hebberling made three experiments on the sulphate by 

 precipitation with barium chloride, which gave in mean Tl 

 = 204.13; extreme difference 0.2. ITe also made two ex- 

 periments on the chloride by precipitation with argentic 

 nitrate. These gave 203.8 and 203.5. The atomic weights 

 assumed are not stated. [If Ag = 107.93 ; CI = 35.457 ; 

 the first analysis of the chloride gives Tl = 203.44. The 

 data for the second analysis are misprinted. If a probable 

 correction of a single figure is made, the data give Tl = 



