1 74 Miscellaneous Intelligence. 



creased, and a beautiful violet colour was developed, in conse- 

 quence of which the vessel was removed from the fire. There re- 

 mained at the bottom of the acid a yellow substance, containing" 

 grey particles, which were dissolved by the hot water used for 

 washing. This water had acquired a brown colour, and the 

 power of colouring solution of starch of a fine blue. After many 

 washings with water, alcohol was used, which in its turn became 

 deeply coloured, and rendered a solution of starch of blue colour. 



In consequence of these appearances the muriatic solution was 

 diluted and distilled, when violet vapour arose, and crystals of 

 iodine condensed in the vessel. Though the yellow matter had 

 boiled some moments with the muriatic acid, it still contained 

 iodine, for 2.38 parts fused with two parts of potash, the residue 

 dissolved in water, saturated with sulphuric acid, and mixed with 

 starch, gave, with a few drops of chlorine, a fine blue colour ; 

 1.63 grains of metallic silver were left. 



Five parts of the mineral were then mixed with two parts of 

 caustic potash, and heated to redness for some time, after which 

 treated with water 4.4,6 parts were left ; these acted upon by 

 nitric acid dissolved without effervescence, leaving a yellow sub- 

 stance resembling chloride of silver ; when dried it weighed 0.8, 

 and was ascertained to be iodide of silver ; it gave 0.415 of 

 silver to nitric acid. 



Hence it appears that as the potash had taken 0.5 parts from 

 the five originally used, which were iodine, and that 0.8 of iodide 

 of silver were formed, which would contain 0.425 iodine, the 

 whole quantity of iodine was 0.925, which divided by 5=0.185, 

 or 18.5 per cent, in the mineral. 



The alkaline solution before mentioned, saturated by nitric 

 acid, became yellow ; and added to solution of starch, with a 

 little chlorine rendered it blue. Nitrate of mercury precipitated 

 it red. A portion of it neutralized by sulphuric acid evaporated 

 to dryness, digested in alcohol, and the alcoholic solution eva- 

 porated, gave quadrangular crystals of hydriodate of potash. 



Besides iodine and silver, the mineral contained sulphur, lead, 

 and carbonate of lime. M. Vauquelin considers it as probable, 

 that the sulphur is combined with the lead and silver, and the 

 iodine with a part of the silver. In confirmation of this it is 

 said, that when boiled with ammonia for some time, iodide of 

 silver is separated from it. This, however, is against the generally- 

 received opinion, that the iodide of silver is insoluble in ammo- 

 nia.-— Ann. de Chim. xxxix. 99. 



5. Selenium in the Sulphur of the Lipari Islands. — Amongst the 

 volcanic productions of the Lipari Islands is a sal-ammoniac, 

 with sulphur in alternate white and brownish orange layers. The 

 colour of the latter has generally been attributed to iron* but the 



