ON IODINE AND BROMINE. 
233 
ART. XXXIX— NOTE UPON THE PREPARATION OF IODINE 
AND BROMINE. By M. Bussy. 
The method of obtaining iodine generally followed, which 
consists in decomposing the mother waters of barilla by 
means of concentrated sulphuric acid, as has been a long time 
known, is liable to give very variable results, in consequence 
of a portion of iodine often passing off by volatilization, either 
in the state of hydriodic acid, or in that of chloride of iodine; 
and in either case there always results a notable loss in the 
quantity of the product. 
To remedy this inconvenience, M. Soubeiran had proposed 
to precipitate the iodine of the mother waters by means of 
sulphate of copper, and afterwards to decompose the iodide of 
copper by peroxide of manganese at an elevated temperature.* 
But this process demands minute attention and many precau- 
tions when it is attempted to obtain the whole of the iodine 
that exist in the mother waters, and we do not believe that it 
has ever been followed in any manufactory. These reasons 
have induced us to make known a mode of proceeding much 
more simple, which has been employed lately by the manu- 
facturers of iodine. It was discovered (if we are correctly 
informed) by M. Barruel, superintendent of the chemical 
works of the faculty of medicine; it consists in precipitating 
the iodine of the mother waters of barilla by means of a 
stream of chlorine. In order to do this, the mother waters are 
evaporated to dryness, to the residue of the evaporation a tenth 
of its weight of peroxide of manganese in powder is added, the 
two are intimately mixed and the combination heated to a 
commencing red heat in an iron boiler, agitating it frequently. 
This calcination has for its object the conversion of the sul- 
phurets, and hyposulphites which are in great abundance in 
* Journal de Pharmacie, t. xiii., p. 427, 
