Further "Experiments and Observations on Iodine. 355 



•f wood, another of metal^ and a third of glass. These Mere 

 stuck through the snow in the garden into the ground, at pro- 

 per distances from each other. Two days afterwards, I ex- 

 amined these rods, and found holes in the snow round the two 

 first similar to those mentioned above ; hut there was not the 

 least alteration in the snow round the glass rod, glass being a 

 nonconductor of those elements." 



But if this experiment be not sufficient to solve the above 

 query, there are other well known phcenomena, from which the 

 same conclusion may be drawn. 



Lynn, Nov. 9, IGM. Ez. WaLKEIK. 



[To be continr.fd.] 



LVII. Further Experiments and Observations on Iodine, By 

 Sir H. Davy, LL.D. F.R.S. KP.ti.L^' 



1. On the triple Compounds containing Iodine and Oxygen. 



1. Itv this communication I shall have the honour of presenting 

 to the Royal Societv a continuation of the inquiries I have made 

 respecting the chemical agencies of iodine, and the properties of 

 certain of its compounds. 



2. I described \\\ mv last paper the action of iodine on fixed 

 alkaline lixivia, and the deflagrating salts it forms. In the first 

 experiment whicli I made on these compounds, I employed the 

 first crystals which fall down from moderately strong solutions 

 of potassa and soda saturated with iodine, which had been puri- 

 fied by being repeatedly acted upon by distilled water :" I now 

 find that this process is not sufficient to free the triple compound 

 from tlie double compound ; and that to obtain them in a state 

 of absolute purity, it is necessary to boil them repeatedly in small 

 quantities of alcohol of specific gravity of from 8'6 to 9*2, which 

 dissolves the double compound, but has little power of action on 

 the triple compound. 



The triple compounds, when purified, present some curious 

 chemical phaenomena, which a minute quantity of the double 

 compound adhering to the crystals that I operated upon, pre- 

 vented me from observing in the experiments I have already 

 communicated to the Society. I shall describe these phoeno- 

 mena as they are produced by the triple compound of potassium, 

 as this substance is most easilv procured in considerable quan- 

 tities, but as far as I have been al)le to observe, the phfenomena 

 presented by the compound of sodiiun are precisely analogous. 



* From die Philosophical IVaiisactioDii fur liil-1, part ii. 



Z 2 Thf 



^ 



