MAGNESIUM. 77 



to 18.3455 barium sulphate. Calculating from the anhy- 

 drous salt Gay-Lussac found from these experiments re- 

 spectively Mg =147.23 and Mg = 148.09 for Ba = 856.8 ; 

 S = 200. The salt was found to contain 51.43 water. 

 [Calculated from the anhydrous salt these data give Mg 

 = 23.55 and 23.68. Calculated from the hydrous salt (7 

 molecules water) the numbers give 24.14 and 24.41, if S = 

 32 ; Ba = 137.08.] Gay-Lussac remarks that the sulphate 

 is partially decomposed at a red heat. (Annal. de Ghim. et 

 de Phys., 13, 1820, 308.) 



T. ScHEERER : U'lQ (O = 16) ; 150.97 (0 = 100). 

 Mean of six experiments on the precipitation of the sul- 

 phate with barium chloride. Extreme difference, 0.79. S 

 = 200.75; Ba=: 855.29. After weighing, the barium sul- 

 phate was treated with dilute HCl and the chloride thus 

 extracted allowed for. {Poggend. Ann., 69, 1846, 535.) 



T. ScHEERER : Si£l (0 = 16) ; 151.33 (0 = 100). 

 Barium sulphate formed as in the last determination was 

 fused with soda, the barium carbonate dissolved in HCl, and 

 reprecipitated as sulphate. In the filtrate additional mag- 

 nesia was found. If the error in the former determination 

 was the same, its corrected value would be as above. 

 {Poggend. Ann., 70, 1847, 407.) 



SVANBERG and NORDENFELDT : 2Jli,.72 (0 = 16) ; 



154.504 (0 = 100). 



Four experiments were made on the calcination of the 

 oxalate, and three on the conversion of the magnesia so 

 obtained into sulphate. The oxalate was dried at from 

 100° to 105° and heated to redness until the weight was 

 constant. The oxide was dissolved in sulphuric acid, evapo- 

 rated and the excess driven off by heat. The oxalate was 

 prepared from the sulphate by precipitation with sodium 

 carbonate and digestion with oxalic acid. The number is 

 the mean of all experiments; extreme difference, 0.514. 

 S = 200.75; C == 75.12; H = 12.48. [Urdmann's Journ. 

 fur Prak. Ghent., 45, 1848, 473.) 



According to Marchand and Scheerer, the data give Mg 

 = 154.27 for S = 200 ; H = 12.5 ; C = 75. 



Marchand and Scheerer: 24..03 (0 = 16); 150.19 

 (0 = 100). 

 Eleven experiments were made in calcining massive mag- 

 nesium carbonate from Frankenstein, and weighing the 



