Sementini on Oxide of Iodine* 77 



II. IODINE AND OXYGKN. I presume that you are acquainted 

 with my experiments on the combinations of iodine constituting 

 the oxide of iodine and the iodous acid*. This second sub- 

 stance was obtained by triturating the chlorate of potassa with 

 iodine, and heating the mixture in a distillatory apparatus. 

 ButWoehler having objected that this substance was a chloride 

 of iodine, and not a distinct acid, I was obliged to vary the 

 experiments, the results of which I am anxious to communi- 

 cate to the members of the Royal Institution without delay. 



In replying to Woehler, I undertake to prove that, on all 

 occasions when iodine is brought in contact with pure oxygen 

 gas, or even with common atmospheric air, at a high tempera* 

 ture, combination takes place, forming first oxide of iodine, 

 and afterwards iodous acid, without the intervention of any 

 other substance. I request your attention to the circumstance 

 of an elevated temperature, because, in the French translation 

 of Berzelius's ' Chemistry,' published at Paris, a low tempera- 

 ture is mentioned, which would prevent the success of the 

 experiment to which I have the honour to refer you below. 



The tube A B of cast brass should be of the diameter of a 

 barometer tube, and ought to terminate at the end B in a capil- 

 lary aperture. It should be fixed to the supports E C, D F. 

 At the extremity A, a bladder G with a stop-cock should be 

 fixed on, which is to be filled with oxygen gas, or even with 

 mere air. The oblong spirit-lamp H H is to be so placed that 

 the flame of its burners may act upon the whole length of the 

 brass tube A B. The extremity B of the tube is to enter the 

 tubular opening of the empty retort K, into which it is to be 

 fixed by luting. Under the bulb of the retort is to be placed 

 the large spirit-lamp L. 



* Quarterly Journal of Science, vol. xvii, 381, and vol. xxiii, 477. 



