554? Intelligence and Miscellaneous Articles. 



does not reduce the chromic acid. Sulphur only is separated, but 

 especially in the first case, the separation requires some hours. If, 

 however, the solutions be heated, then a notable quantity of sul- 

 phuric acid is formed, sulphur being also always separated, but in 

 small quantity. 



A solution of iodate of potash, or of soda even, when cold, is de- 

 composed by sulphuretted hydrogen, and a great quantity of sul- 

 phuric acid is formed. It then becomes of a reddish brown colour, on 

 account of the iodine set free, but the ulterior action of the sulphu- 

 retted hydrogen decolorates it. The deposit of sulphur, which oc- 

 curs in this case, is caused by the conversion of the iodine set free 

 into hydriodic acid. The solution reddens litmus paper sensibly 

 after decomposition, and contains sulphuric and hydriodic, but no 

 iodic acid. After the destruction of the sulphuretted hydrogen by 

 a solution of oxide of copper, nitrate of silver produces in the 

 liquor separated from the sulphuret of copper, a precipitate inso- 

 luble in ammonia. It is well known that a mixture of free iodine 

 and water is converted by sulphuretted hydrogen into hydriodic 

 acid, accompanied with a deposit of sulphur, and without forming 

 any sulphuric acid. If, however, the mixture be heated during the 

 action of the sulphuretted hydrogen, sulphuric acid is formed in 

 small quantity. A solution of bromate of potash acts with sul- 

 phuretted hydrogen like that of iodate of potash. In the cold solu- 

 tion there are produced sulphuric and hydrobi'omic acids and a de- 

 posit of sulphur. 



Chlorate of potash, on the contrary, is not decomposed by sul- 

 phuretted hydrogen, either cold or even at a boiling heat. Neither 

 sulphuric nor hydrochloric acid is formed, and the liquor does not 

 lose its neutrality. If it assume an opalescent appearance, on account 

 of a trace of sulphur which is separated, it is derived merely from 

 the decomposition of some sulphuretted hydrogen by the air of the 

 atmosphere. If the sulphuretted hydrogen contained in the solution 

 be destroyed by oxide of copper, a salt of silver added to the solu- 

 tion after the separation of the sulphuret of copper, produces no 

 precipitate of chloride of silver. The solution of oxichlorate of 

 potash acts exactly the same as that of the chlorate, with sulphuret- 

 ted hydrogen. — Journal de Pharmacie, Aout, 1839. 



WHITENESS OF PRECIPITATED SULPHUR. BY H. ROSE. 



It is a well-known fact, that sulphur, which separates from liquids 

 in a state of minute division, has not the usual yellow colour of sul- 

 phur, but is whitish or grayish. The cause of this difference of co- 

 lour has been long a subject of discussion, and it has been gene- 

 rally concluded that it arises from the different states of division. 

 If milk of sulphur and flowers of sulphur be examined by the micro- 

 scope, the grains of the milk of sulphur are certainly observed to be 

 the smaller of the two ; but this is unquestionably not the only cause 

 of the difference between them. 



In the opinion of M. Rose it has escaped notice, that the peculiar 

 yellow colour of sulphur is wanting only in those cases in which it 



