Furtlier Experiments and Olservatlons on Iodine. 561 



Acrid bitter substance, very similar in its taste to harytnne^ 

 (fused muriate of baryta,) not decompo'iable when heated to 

 whiteness unless oxygen is present, but when it is heated in con- 

 tact with oxygen, oxygen is absorbed, and a part of its iodine 

 expelled. 



IVIagnesia dissolved in hvdroionic acid without effervescence, 

 and the solution evaporated gave a solid substance, having a 

 taste very similar to muriate of magnesia. Like that salt, it 

 partly lost its acid by a red heat; but a portion remained not. 

 decomposable out of the contact of air, but which instantly af- 

 forded iodine v/hen heated in contact v/ith oxygen. 



I dissolved glucina, ittria, and zircona in the hydroionic acid ; 

 they formed neutral saline couipounds. The compound of hy- 

 droionic acid and glucina was less soluble and m.ore astringent 

 in taste than the muriate of glucina, and v;as entirely decom- 

 posed when heated in the open air, affording hydroionic acid 

 and iodine. 



The compound formed from ittria was more soluble, and 

 highly astringent ; that formed from zircona astringent, v/ith 

 more of bitterness. Both these salts were decomposed when 

 heated in the atmospliere, at a low red heat ; a smell of hydro- 

 ionic gas was perceived, iodine was produced, and the earth* 

 remained. 



3. I mentioned, in a note datcrl Montpcllier, .Ian. 10, (con- 

 taining a correction for my last comnmnication to the Society,) 

 that the alkaline property which I at first supposed to belong to 

 the compounds of potassium and sodium with iodine, depended 

 upon some undecom))osed sui)carbonate of potassa mixed with 

 the hydrate of potassa I employed, as the subcarbonate of po- 

 tassa is decomposed by iodine and carbonic acid set free, I had 

 not thought it probable that the subcarbonate of potassa could- 

 interfere with this result. But I find that if the subcarbonate 

 exist at all in the lixivium, a portion of it always remains unde- 

 composed. I find likewise, tliat when a solution of iodine in 

 lixivium of potassa is rendered perfectly neutral, or even slightly 

 acid by hydroionic acid, a strong red heat renders the solid sub- 

 stance obtained siightlv alkaline, provided it be in contact Avith 

 air. Whether the separation of iodine by oxygen, in this in- 

 istance, depends upon some effect of the moisture contained in 

 the atmosphere, or upon the continued action of fresh portions 

 of oxygen on the same surface of the compound, it is not easy 

 to say ; but a similar effect I fiiid is produced upon potassile, 

 (fluate of potassa;) this substance gains the power of reddening 

 paper tinged with turmeric, by being strongly heated in contact 

 With flic air. 



The power of neutralizing acids does not belong to the true 



compound 



