Litelligence a?id Miscellafieous Articles. 499 



excess may be used which would react upon the iodine precipitated. 

 This excess of chlorine is especially to be apprehended, when it i^ 

 also intended to separate from the same mother-waters the bro- 

 mine which they contain. 



In order to avoid adding excess of chlorine, the liquor which is 

 supposed to be near saturation, may be suffered to settle for a short 

 time, and the current of chlorine being interrupted it is to be di- 

 rected on the surface of the liquid. If it contain any iodide in solu- 

 tion, a pellicle of iodide will be observed to form on the surface ; 

 this effect is not produced when all the iodine is precipitated ; in the 

 latter case the liquor becomes quickly clear and retains only a 

 reddish tint. 



PREPARATION OF BROMINE. BY M. BUSSY. 



The separation of bromine, as usually performed, also involves 

 great difficulties, which may be avoided by the following process. 



This process greatly resembles the preceding one ; it is founded, 

 like it, upon the great affinity of chlorine and the property which it 

 possesses of displacing bromine from its combinations. It also 

 includes the employment of the mother-waters of iodine, which 

 without it are useless. Take the mother- waters of kelp, after having 

 separated the iodine by chlorine as above described. These mother- 

 waters contain a metallic bromide, when care has been taken to 

 avoid the use of more chlorine than sufficient to precipitate all the 

 iodine. Add to 1250 parts of these mother-waters, thirty-two parts 

 of powdered peroxide of manganese, and twenty-four parts of sul- 

 phuric acid of sp. gr. 1'848 : the whole is to be put into a tubu- 

 lated glass retort, to which a tubulated receiver is to be adapted, 

 and to this a tube which is immersed in a test tube. The retort 

 and the receiver, as well as the receiver and the tube, ought to fit 

 sufficiently well without the use of lute or corks, as they would be 

 inevitably destroyed by the action of the chlorine. All being thus 

 arranged, the retort is to be heated, so as to boil the liquid ; the 

 bromine condenses in the receiver in the form of red oily striae, with 

 a small quantity of water ; the operation is to be discontinued when 

 red vapours cease to be produced. On heating the receiver gently, 

 without dismounting the apparatus, the bromine will pass into the 

 test-tube, where it will condense on cooling. 



The mother-waters which have been made use of may be re- 

 jected, on ascertaining by the addition of a fresh quantity of sul- 

 phuric acid and peroxide of manganese that they contain no more 

 bromine. Journal de Pfiarmacief January 1837. 



ON THE RED AND WHITE OXIDE OF PHOSPHORUS. BY 

 M. MULDER. 



Pelouze considers the white crust which covers old sticks of 

 phosphorus as hydrate, and H. Rose regards it as differing from 

 common phosphorus only by its state of aggregation. The red 

 powder which sometimes covers phosphorus may be prepared by 



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