230 ANNUAL OF SCIENTIFIC DISCOVERY 



The electro-negative metal has the following properties: it is thrown 

 down, with a brown color, by sulphuretted hydrogen from an acid solution, 

 and the precipitate is soluble with a brown color in ammonia and sulphuret of 

 ammonium. Its solution in nitro-muriatic acid, when slowly evaporated, 

 deposits a solid body of a brownish-yellow color. Before the blowpipe, this 

 gives colorless globules, with salt of phosphorus, and furnishes no metal with 

 soda upon charcoal. 



The properties of the electro-positive metal are as follow: From a solu- 

 tion of iron, mixed with a sufficient quantity of acetate of soda, it is thrown 

 down by a sulphuretted hydrogen, together with iron and a small amount of 

 zinc which is contained in the ore. After the precipitate has been partially 

 dried upon the filter, iron and zinc may be removed by dilute muriatic acid, 

 and afterwards nitric acid. The residue, calcined with access of air, and 

 afterwards fused with carbonate of soda, yields a grayish-yellow substance, 

 which, when calcined in hydrogen gas, furnishes a black powder, which 

 burns in the air to a grayish-yellow body. The black powder obtained by 

 reduction with hydrogen gas, is dissolved with extreme difficulty by nitric 

 acid, but more readly nitro-muriatic acid; in this solution alkalies form a 

 yellowish-brown, flocculent precipitate ferrocyanide of potassium a blue or 

 green one. Before the blowpipe, it gives a colorless globule, Avith salt of 

 phosphorus ; this becomes opalescent in the inner flame, and Avhen a large 

 quantity is present, gray. It is not in the least attracted by the magnet. 



IODINE IN ATMOSPHERIC WATERS. 



M. Marchant, in the Comptes Rendus, Xo. 17, 18-38, publishes the details of 

 a great number of analyses, Avhich seem to proA r e beyond a doubt that 

 iodine and bromine (traces) " are constantly and normally present in atmos- 

 pheric Avaters." 



A NEW METHOD FOR DETECTING THE PRESENCE OF IODINE AND 



BROMINE IN MINERAL WATERS. 



The folloAving paper, by M. M. Henri and Humbert, is copied from the 

 Comptes Rendus : 



The mineral Avater, or the residue from its evaporation, more or less con- 

 centrated, is treated AA'ith an acid solution of nitrate of silver. The pre- 

 cipitate Avhich takes place ought to contain, in the state of silver salts, all 

 the chlorine, bromine, and iodine Avhich was in the Avater. The precipitate 

 is AA-ashed and carefully dried, and in this state it is mixed intimately Avith a 

 small quantity of cyanide of silver, then introduced into a tube, at one of 

 the extremities of which it is fixed betAveen tAA r o small plugs of Avadding or 

 flax. A current of chlorine gas, perfectly dry, is made to pass OA r er the 

 mixture, Avhilst the corresponding part of the tube is gently heated. The 

 iodine, bromine, and cyanogen are displaced, and, combining together, con- 

 dense in the coldest part of the tube in beautiful white and crystalline rings 

 of iodine and bromide of cyanogen. The tube is afterwards closed at both 

 its extremities, and reserved for testing. 



The iodide and bromide of cyanogen possess physical and chemical prop- 

 erties which preA r ent their being confounded Avith other compounds. The 

 iodide sublimes at a temperature of 113, and the bromide at a temperature 

 of 59 Fahrenheit. This difference in their volatility permits of their being 

 mechanically separated; by plunging the tube containing these compounds 



