Intelligence and Miscellarieous Articles, 157 



requisite excess of oxygenated water is certain to be employed when 

 hyposulphites, sulphates, or sulphurets are present ; besides, the 

 hydrochloric acid employed in the preparation of the oxygenated 

 water, acts an important part, for it serves to set hydriodic acid free, 



Ba0«+(C1H)« + IH, KO + HO=BaO, CIH + KO, C1H+2(H0) + I. 



Although it is unquestionable that the hydrochloric acid, by react- 

 ing on the binoxide of barium, in the presence of water, produces 

 oxygenated water, the author was desirous of satisfying himself that 

 it was in fact HO^ which actually produced the result obtained ; for 

 this purpose he substituted tartaric for hydrochloric acid, and ob- 

 tained the same result. M. Thenard had also described the decom- 

 position of hydriodic acid by pure oxygenated water. 



When the iodides are mixed with chlorides, sulphurets, sulphites or 

 hyposulphites, the process is equally correct ; only, as by the action 

 of hydrochloric acid on the sulphuret sulphuretted hydrogen is pro- 

 duced, which is decomposed by oxygenated water, and the hypo- 

 sulphites and sulphites are converted into sulphate by absorbing 

 oxygen, a larger quantity of oxygenated water is required than if 

 the iodide was pure. 



The hyposulphites and sulphites, on becoming sulphates, produce 

 a precipitate of sulphate of barytes in the liquor ; this might delay 

 the action, if agitation were not employed to detach the sulphate of 

 barytes from the surface of the binoxide of barium : it is also a pre- 

 caution which ought always to be adopted to increase the production 

 of oxygenated water. By this process the presence of iodine is 

 readily detected in the urine of a patient taking 0*10 centigr. of 

 iodide of mercury morning and evening. In the same urine no 

 iodine could be detected by means of chlorine ; this is therefore a 

 case in which, notwithstanding every precaution, the iodine passed 

 undetected by chlorine. 



This process detects the presence of iodine in the ash of sponge. 

 A drop of a solution of 0010 grm. of iodide of potassium dissolved in 

 a litre of water, produced, each time that it fell into the tube, a ma- 

 nifest blue colour at the surface. By agitation the blue colour dis- 

 appeared, and the liquor assumed a rose tint ; on adding another 

 drop, a fresh blue colour is obtained at the surface. This process, 

 therefore, very easily indicates less than -^^^ of iodide of potassium. 

 The process is the same for bromine, excepting that instead of starch 

 aether is employed; agitation is used, the bromine dissolves in the 

 aether, and it becomes of a more or less deep yellow colour accord- 

 ing to the quantity. 



When, however, iodides and bromides occur mixed, they are de- 

 tected by adding an excess of starch and of aether. The iodine com- 

 bines with the starch, and the bromine, dissolving in the aether, rises 

 to the surface ; so that the blue colour is obtained below, and the 

 yellow tint high up. — Comptes Rendus, Avril 30, 1849. 



