OF ARTS AND SCIENCES. 319 



II. 0.4604 grra. of the air-dried salt lost, at 100°, 0.0307 grm. II2O, 

 and gave 0.2780 grm. K^SO,. 

 III. 0.5428 grm. of the air-dried salt gave 0.3281 grm. K^SO^. 



Argentic Mucoxybr ornate^ Ag2C^HBrO^. — Argentic nitrate added to 

 a sohition of the free acid, or one of its salts, throws down a crys- 

 talline precipitate of the silver salt. When this is warmed with water, 

 argentic bromide is at first formed, then reduction takes place. When 

 heated in a slightly ammoniacal solution, it is immediately blackened. 

 It dissolves readily in dilute nitric acid, but the solution soon grows 

 turbid with the separation of argentic bromide. The dry salt explodes 

 on heating, or on moistening with concentrated nitric acid. For analy- 

 sis, the salt was made by precipitating an excess of argentic nitrate 

 with a dilute solution of the barium salt. 



I. 0.3974 grm. of the salt dried in vacuo over H^SO^ gave, on pre- 

 cipitation with HBr, 0.3634 grm. AgBr. 

 II. 0.5478 grm. of the salt dried in vacuo over H^SO^ gave, on pre- 

 cipitation with HBr, 0.5034 grm. AgBr. 



III. 0.5455 grm. of the salt dried in vacuo over HgSO^ gave, on pre- 



cipitation with HBr, 0.4999 grm. AgBr. 



IV. 0.5866 grm. of the salt dried m vacuo over H.,SO^ gave, on heat- 

 ing in sealed tube with diluted nitric acid, 0.2672 grm. AgBr. 



IV. 



19.38 



A solution of the barium salt yielded, with plumbic nitrate, a heavy 

 yellow, semi-crystalline precipitate, which, when dried over sulphuric 

 acid, gave on analysis percentages of lead and bromine which only 

 approximated those required by the formula PbC^HBrO^. 



Dimethyl 3Iucoxyhr ornate, C^HBrO^(CFL)2. — The dimethyl ether 

 of mucoxybromic acid can readily be formed by the action of methyl 

 iodide upon the dry silver salt. If the methyl iodide is slowly added 

 to the silver salt, so much heat is evolved that a violent and even dan- 

 gerous explosion ensues. The silver salt must therefore be added in 

 small portions to an excess of methyl iodide, or must be suspended in 

 dry ether before adding the methyl iodide. The product of the re- 



