484 



light, forming a white fusible substance soluble in water, and acrid 

 to the taste, from which iode is again separated by sulphuric acid. 



lode was found to combine with chlorine into a yellow volatile 

 solid, from which iode was again separated by solution of potash, not 

 in excess. 



When iode is heated with oxygen gas, or with oxymuriate of pot- 

 ash, it undergoes no change. When heated in the presence of iron, 

 zinc, tin, lead, or mercury, out of the contact of air, it forms com- 

 pounds that are fusible and volatile, and have a yellow, orange, or red 

 colour, excepting the compound formed with zinc, which is white. 



The compound of iode and iron, when exposed to an alkaline so- 

 lution, yields oxide of iron, but it combines with dry ammoniacal gas 

 without decomposition ; whence the author infers that the formation 

 of oxide depends on the presence of water. 



When iode is heated in hydrogen, the gas expands considerably, 

 and the compound is found to be highly acid, rapidly absorbed by 

 water, forming a liquid acid without colour, but becoming tawny by 

 dissolving an excess of iode. 



lode combines with phosphorus, producing heat without light ; a 

 solid compound is formed that is fusible and volatile ; and a strongly 

 acid gas is extricated, that is readily absorbed by water. When po- 

 tassium or mercury are heated in this gas, they extricate hydrogen 

 equal to half the volume of the gas, and are found combined with 

 iode ; so that this gas appears to arise from the presence of hydrogen 

 probably contained in the phosphorus. 



When the fusible compound with phosphorus is acted upon by 

 water and heated, much gas arises that is acid and spontaneously in- 

 flammable, and the remaining liquid is found to contain hydrophos- 

 phorous acid. 



When iode is thrown into a moderately strong solution of potash, 

 two compounds are formed, as in the formation of oxymuriate of 

 potash. The first appears in crystals, which form immediately, and 

 fall to the bottom of the solution, and are analogous to hyperoxymu- 

 riate of potash, and very similar to it in properties. But the solution 

 contains a different salt, without excess of oxygen, being simple iodate 

 of potash. The crystals are sparingly soluble in water, deflagrate 

 when mixed with charcoal, and yield abundance of oxygen when 

 heated. 



By passing the purple vapour over red-hot potash, oxygen is also 

 expelled ; and it appears that oxygen quits the triple compound at a 

 red heat. 



The affinities of this body for potassium and the metals are inferior 

 to those of chlorine for the same bodies ; and accordingly it is ex- 

 tricated from them when the compounds are exposed to oxymuriatic 

 gas. 



When the compound of iode with potassium is acted upon by sul- 

 phuric acid, a different class of phenomena appear in consequence of 

 the decomposition of the acid, and of the water present. Sulphureous 

 acid is disengaged, mixed with the acid gas formed by the union of 



