MANGANESE. 79 



solution evaporated nearly to dryness, and the oxalate 

 thoroughly washed. Bahr says that the presence of alkalis 

 could not be suspected, S =: 200. {Erdmanri's Journ. filr 

 Prak. Chem., 66, 1852, 310 ; (Efversigt af Akad. Fcerh., 1851, 

 303.) 



Scheerer says that oxide so prepared retains carbonic 

 acid, that sulphate is carried ofl" in heating the sulphate to 

 redness, and that the presence of alkalis is to be suspected. 

 {Erdmann's Journ. filr Prak. Chem., 66, 1852, 489.) 



J. Dumas : 24.6 (O =16). 



Dumas made eleven experiments on the titration of mag- 

 nesium chloride with argentic nitrate. He found great 

 ditficulty in preparing pure chloride, and does not feel con- 

 fident of his results. The number is the mean ; extreme 

 difference, 0.28. Ag = 108 ; CI = 35.5. The chloride 

 was prepared from various salts, but was in all cases finally 

 heated in an atmosphere of HCl. Dumas points out, 

 however, that this process does not remove oxide if present. 

 {AnnaL de Chim. et de Phys., (3,) 66, 1859, 129.) 



MANGANESE. 



Regnault has determined the specific heat of manganese. 

 It corresponds to an atomic weight of about 55. [Gmelin- 

 kraut, I. c.) 



J. J. Berzelius : 66.93 (O = 16) ; 355.787 (O = 

 100). 



By dissolving manganese in nitric acid, evaporating and 

 heating to a low red, Berzelius found 100 Mn = 142.16 

 oxide. It was not known at the time that the oxide might 

 be partially reduced by this process. {Poggend. Ann., 8, 

 1826, 185 ; and Jahresbericht, 9, 136.) 



J. A. Arfvedson : 66.25 (O = 16) ; 351.56 (0 = 

 100). 



From 1.508 chloride Arfvedson obtained 3.408 argentic 

 chloride. If Ag = 1351.607 ; CI = 221.325 ; the number 

 follows. {Berzelius' Jahresbericht, 9, 1829, 136 ; Afhandl. i. 

 Fysik., 6, 236.) 



