further Experiments and Ohsexvations on Iodine. S$5 



TOTlst contain five proportions of chlorine to one of iodine, to 

 produce a triple compound without the precipitation of iodine, 

 it is however most probable that some double compound of 

 iodine is always formed, as a solution must be extremely diluted 

 indeed to contain five proportions of chlorine to one of iodine. 



When the solution of chlorionic acid is poured into solution 

 of muriate of barNta, v/ater must be decomposed to ftu-ni&h hy- 

 drogen to the muriatic acid, and oxygen to the triple compound, 

 and in this case some double compound of iodine and barium 

 must be formed and remain dissolved in the solution. 



From the action of chlorionic acid on metallic solutions, I am 

 inclined to believe that triple compounds of the common metals, 

 oxygen and iodine m.av be formed by means of it. It occasions 

 a copious precipitate v.ithout effervescence in the solution of 

 sulphate of iron, and in the solution of nitro-muriate of lead, 

 and tin, and of nitrate of copper, and from analogy it is pro- 

 bable that tliese precipitates consist of ti-ie metal, oxygen, and 

 iodine. 



2. I thought it proba!)le fi:om the rapid action of tin on iodine, 

 that tin-foil would l)ur!i in the vapour of iodine, but on intro- 

 ducing it into the violet-coloured gas in a small retort made very 

 hot, though the combination was instantaneous, yet no light was 

 ap])arent. 



I tb.ought it possible that the acid properties of the com- 

 pound of tin and iodine, which I hare described in my last com- 

 munication to the Society, might depend upon the decomposi- 

 tion of water and upon the formation of hydroionic acid. On 

 this idea I distilled the solution of it in water, hoping if hydro- 

 ionic acid were formed, that I should obtain some in this pro- 

 cess ; but the fluid that came over was merely water coloured 

 by a minute quantity of iodine, and the oranga-coloured sub- 

 stance which remained when dissolved in water, exhibited tlie 

 same acid properties as before, and combined with ammonia 

 without affording any oxide. 



The compound of iodine and iron when dissolved in water 

 exhibited acid properties, but when the solution was distilled it 

 yielded hydroionic acid and deposited oxide of iron, and the en- 

 tire solution acted on by ammonia, affordc<l an olive-coloured; 

 precipitate in great abundance. 



4. Oil the Action of some compound Gases on Iodine. 

 1. I heated some iodine in a dry glass globe filled with sul- 

 phuretted hydrogen ; there \\\i a considerable absorption of gas, 

 no sulphur was deposited, and a rcddish-broun fluid was formed, 

 which -when thrown into water rendered it st; ongly aoid and 



deposited 



