394 Intelligence and Miscellaneous Articles, 



days in a corked phial at a temperature of from— 3° to— 4°, yielded 

 1*477 of sulphate of barytes. 



One hundred parts of these crystals were then formed of — 



I. II. III. 



Sulphurous Acid 76-02 79-16 76-82 



Water 23-98 20-84 23'18 



taking as the basis of the calculation the quantity of anhydrous sul- 

 phurous acid, corresponding to the sulphate of barytes. 



For one equivalent of anhydrous sulphurous acid (H=l) 32-15, 

 we have — 



I. II. III. 



Water 10-14 8-46 9*73 



These numbers correspond to 1 equivalent of water = 9-01, so nearly, 

 that no doubt can be entertained of the compound in question being 

 formed of equal equivalents of sulphurous acid and water. 



It appears also that there exists another compound of sulphurous 

 acid and water. If the liquor which separates from the hydrate in 

 question, be exposed to a temperature — 6° to — 7° C, it becomes a 

 crystalline mass which appears to have a lamellar structure. When 

 the temperature approaches 0°, these crystals re-dissolve, and at 

 — 2° C. the whole becomes liquid, a phsenomenon which is not ex- 

 hibited by the preceding compound. The author has not yet ascer- 

 tained the composition of the last described crystals. — L'Institut, 

 Octobre 10, 1849. 



ON THE METHODS OF ASCERTAINING THE QUANTITY OF 

 BROMINE IN SOLUTION IN MOTHER-WATERS. BY M. FEHLING. 



Three methods are adopted for determining the quantity of bromine 

 contained in mother-waters or mineral waters. 



1st. The first consists in precipitating by nitrate of silver the 

 chlorine and bromine contained in these liquids, and in treating the 

 mixture of chloride and bromide of silver by chlorine gas, which 

 displaces the bromine. 



As the atomic weight of bromine is higher than that of chlorine, 

 the quantity of bromine is readily calculated by multiplying the dif- 

 ference of weight obtained by the coefficient 1-7947, which is merely 

 the equivalent of bromine divided by the difference of the equivalents 

 of bromine and chlorine. This method is not precise except when 

 the liquids contain a notable quantity of bromine. 



2nd. The second process proposed by M. Heine, consists in dis- 

 placing the bromine by sether, and appreciating the quantity accord- 

 ing to the intensity of the tint of the ethereal solution. 



In operating in this manner on 60 grammes of liquid containing 

 from 0-002 to 0-020 of bromine, and avoiding the influence of the 

 sun's rays, the quantity of bromine set free by the chlorine may be 

 estimated to within about one or two tbousaiadtbs. 



