296 On Iodine. [April, 



Having in my present communication rescued another discovery 

 from Mr. Hume's extensive grasp, and restored it to the rightful 

 owner, I expect from him a repetition of the invectives of which 

 he has been so liberal, with such scanty additions as even his well- 

 stored vocabulary can now afford ; but having, as I conceive, an- 

 swered Mr. Hume's arguments, I shall hold myself excused from 

 entering upon a mode of discussion, in which success is inseparable 

 from disgrace. 



I remain yours, very respectfully, 



29, PouUry, Feb. 22, 1815. Rl CHARD PhiLLIPS. 



Article IX. 

 A Memoir oji Iodine. By M. Gay-Lussac. 



{Continued from p. 214.) 



Comlinatio7i of Iodine tvitli Chloi-ine. 



Dry iodine rapidly absorbs chlorine, producing a heat which rises 

 to 212°. The compound has in some parts a fine orange-yellow 

 colour; in others, an orange-red. The yellow parts contain more 

 chlorine than the red; they are likewise more volatile. Though I 

 passed a great deal of chlorine over the iodine, yet the greatest 

 part was not saturated. We shall see immediately by what cha- 

 racters this point can be determined. To the red compound of 

 iodine and chlorine I give the name of stihchloruret of iodine, 

 though it does not appear to me to liave fixed proportions. To the 

 yellow compound I give the name of chloruret. 



Both of these compounds speedily deliquesce in the air. The 

 solution of the subchloruret is a deeper orange-yellow the more 

 iodine it contains. The solution of the chloruret is colourless when 

 tlie excess of chlorine is driven off, and then the mutual saturation 

 of the two constituents seems to be complete. Both solutions are 

 very acid, and destroy the colour of the solution of indigo in sul- 

 phuric acid. When the solution of the cliloruret is saturated with 

 an alkali, it is changed completely into iodate and hydro-ciilorate. 

 When too long exposed to the light, it becomes coloured. It 

 dissolves a great quantity of iodine, and then assumes the characters 

 of subchloruret. Heat disengages chlorine from it, and the iodine 

 being then in excess, the liquid assumes the characters of subchlo- 

 ruret. The solution of the subchloruret is volatilized without 

 decomposition. Light does not produce any further alteralion upon 

 it. When saturated witii an alkali, it gives iodate and hydro chlo- 

 rate ; but if the alkali be cautiously added, we obtain a precipitate 

 of iodine, which disappears on the addition of more alkali, and 

 then hyd;iodatc and iodate are formed. 'J'hus the subdiloruret is 



