128 THE ATOMIC WEIGHTS. 



The chloride of manganese was fused in a current of dry 

 hydrochloric acid, and subsequently precipitated with a 

 solution of silver. From the subjoined weighings I calcu- 

 late the ratio given in the third column between MnCl, and 

 100 parts of AgCl : 



4.20775 grm. MnCl^ = 9.575 grm. AgCl. 43-945 \ gg^^gji^j 

 3.063 " = 6.96912 " 43-950 i 



12.47 grains MnClj = 28.42 grains AgCl. 43-878 — Turner. 



Mean, 43.924, ± .015 



Hence the molecular weight of MnCU is 125.662, ±z .045. 



Many years later Dumas* also made the chloride of man- 

 ganese the starting point of some atomic weight determina- 

 tions. The salt was fused in a current of hj^drochloric acid, 

 and afterwards titrated with a standard solution of silver 

 in the usual way. 100 parts of Ag are equivalent to the 

 quantities of MnCL, given in the third column : 



Mean, 58.321, d= .001 



Hence MnCl. = 125.594, ± .011. This, combined with 

 Berzelius and Turner's figures, gives MnCl, = 125.598, 

 ± .011. And Mn = 54.858, ± .031. 



An entirely different method of investigation was followed 

 by V. Hauer,t who, as in the case of cadmium, ignited the 

 sulphate in a stream of sulphuretted hydrogen, and deter- 

 mined the quantity of sulphide thus formed. I subjoin his 

 weighings, and also the percentage of MnS in MnSOi as 

 calculated from them : 



* Ann. Chem. Pharm., 113, 25. i860. 

 f Journ. fUr Prakt. Chem., 72, 360. 1857. 



