THALLIUM. 93 



Johnson and Allen 117.499, ifc .025 Cs = 132.706 



Bunsen 117.467, dr .013 " = 132.661 



Godeffroy 1 17. 164, i .023 " =132.227 



General mean 1 17.413, ±z .010 



Hence Cs = 132.583, ± .024 ; or, if = 16, Cs = 132.918. 



THALLIUM. 



The atomic weight of tliis interesting metal has been 

 fixed by the researches of Lamy, Werther, Hebberling, and 

 Crookes. Lam}^ and Hebberling investigated the chloride 

 and sulphate ; Werther studied the iodide ; Crooke's experi- 

 ments involved the synthesis of the nitrate. The last men- 

 tioned work was so thorough and admirable that the other 

 researches are included here only for the sake of historical 

 completeness. 



Lamy* gives the results of one analysis of thallium 

 sulphate and three of thallium chloride. 3.423 grammes 

 TKSO4 gave 1.578 grm. BaS04 ; whence 100 parts of the 

 latter are equivalent to 216.920 of the former. In the thal- 

 lium chloride the chlorine was estimated as silver chloride. 

 The following results were obtained. In the third column I 

 give the amount of TlCl proportional to 100 parts of AgCl: 



3.912 grm. TlCl gave 2.346 grm. AgCl. 166.752 



3.000 " I. 8015 " 166. 52S 



3.912 " 2.336 " 167.466 



Mean, 166.915, =b .1905 



Hebberling'st work resembles that of Lamy. Reducing 

 his weighings to the standards adopted above, we have from 

 his sulphate series, as equivalent to 100 parts of BaS04, the 

 amounts of TI2SO4 given in the third column: 



* Zeit. Anal. Chem., 2, 211. 1863. 

 I Ann. Chem. Pharm., 134, 11. 1865. 



