Iudons Acid — Ledererite. 393 



cipitation of iodine, though the yellow colour totally disappeared im- 

 mediately on the union of the' acid with the alkali. This solution, 

 when evaporated, formed a salt, differing from the iodate of ammonia 

 by the following properties. 



The iodite of ammonia is less efflorescent than the iodate j its taste 

 is less decidedly salt; it detonates, if heated in an open vessel, but 

 with a longer escape of vapours of iodine ; its colour is a light green- 

 ish tint. The solubility of the two salts is very different, the iodite 

 being soluble in little more than half the quantity of water required to 

 dissolve the iodate. 



Although I have not yet effected an exact analysis and comparison 

 of the two salts, yet, when I caused equal quantities of them to de- 

 tonate with a proper apparatus, and particularly in small long-necked 

 retorts, I observed the following effects, which appeared to me of 

 some weight : these are, the production of aqueous vapours much 

 more considerable in the detonation of the iodite, and the greater 

 quantity of iodine obtained from its detonation. This is easily recog- 

 nised by observing, before and after the detonation, the weight of the 

 retorts which are used. 



I am now employed in combining this acid with other bases, and in 

 repeating with still greater accuracy the above experiments ; but I 

 think I may fairly consider as an acid in ous the combination of the 

 iodic acid with the oxide of iodine, if, without being decomposed or 

 altered, it forms with the bases particular compounds, just as we call 

 nitrous acid the union of the nitric acid with the oxide of nitrogen, 

 which does not form similar compounds, but, at the moment of com- 

 bining with the bases, the oxide gas of nitrogen separates from it, and 

 forms, as I have said, nitrates. 



I have discovered in zinc a new and important quality, which I am 

 surprised has not been before known. If, when the zinc is fused to a 

 red heat, the vessel is removed from the fire, its combustion will con- 

 tinue as long as the least particle of metal remains, provided it be kept 

 continually agitated, and the oxide which is formed be gradually re- 

 moved. When a large quantity of the metal is employed, it will be 

 curious to see a combustion continue for a very long time, without the 

 addition of any other heat than that which is developed by the metal 

 itself. 



A grey oxide is thus formed, with qualities very different from the 

 common oxide : its specific gravity is much greater, and it absorbs no 

 carbonic acid from the atmosphere. 



I am much occupied at present with this phenomenon, which is re- 

 markably beautiful in itself, and which may, in time, lead to the dis- 

 covery of other important facts. 



Linoi Semkntini. 



E. Daniell, Esq., Secretary of the 

 Royal Institution, London. 



LEDERERITE NOT A NEW MINERAL. 

 A Correspondent has sent us a small specimen of the supposed new 

 mineral Ledererite, imperfectly described in our last Number, p.317 ; 

 Third Series. Vol. 4. No. 23. May 1834. 3 E 



