192 Extracts from Berzelius's Annual Report for 1843. 



method with arsenious acid. One hundred volumes of water dissolved 

 the foUowins; volumes of chlorine o;as.: 



de Chim. I, 299) has proposed a modification of the ordinary method. 

 He employs the bromide or the iodide of potassium in the place of the 

 pulverized glass, and thus obtains a much larger quantity of the hy- 

 dracids, because the salt employed is decomposed by the phosphoric 

 acid which it converts into phosphate of potash. The proportions that 

 react are, 2 ats. of the salt of potash, 5 ats. of the bromine or iodine, 

 1 at. of phosphorus, and 7 ats. water. To obtain the hydrobromic acid, 

 M. Millon employs 15 grammes of the bromide potassium and a little 

 water, to which he adds 25 grammes of bromine, and 2 grammes of 

 phosphorus cut up in small pieces. The hydrobromic acid soon begins 

 to be so rapidly disengaged, that it becomes at times necessary to plunge 

 the vessel in cold water to check the action. When the disengagement 

 of gas becomes slow, it is aided by a little heat. In the preparation of 

 the hydriodic acid, it is necessary to heat from the beginning, and the 

 escape of gas is very uniform. 



Cyanogen. — M. Wohler has shown that when nitrogen gas con- 

 taining moisture is passed over a mixture of potash and charcoal cya- 

 nide of potassium is formed, but if the gas be dry no cyanogen is 

 formed. 



Combinations analogous to Cyanogen formed hy the comiination of 

 Boron and Silicon loith Nitrogen. — M. Balmain (Phil. Mag. XXI, 270) 

 has described some very interesting experiments which seem to prove 

 that boron and silicon form with nitrogen combinations endowed with 

 the halogen properties of cyanogen. When a mixture of 7 parts of 

 anhydrous boracic acid and 20 parts of cyanide of potassium are ex- 

 posed in a well covered crucible to a white heat, there remains after 

 cooling a porous mass. The proportions of this mixture are calculated 

 in such manner as that the carbon of the cyanide of potassium suffices 

 exactly to reduce the boracic acid in being converted into carbonic 

 oxide. The substance as taken from the crucible is white and porous, 



