Page:Philosophical Transactions - Volume 104.djvu/573

Rh 2. I thought it probable from the rapid action of tin on iodine, that tin foil would burn in the vapour of iodine, but on introducing it into the violet coloured gas in a small retort made very hot, though the combination was instantaneous, yet no light was apparent.

I thought it possible that the acid properties of the compound of tin and iodine, which I have described in my last communication to the Society, might depend upon the decomposition of water and upon the formation of hydroionic acid. On this idea I distilled the solution of it in water, hoping if hydroionic acid were formed, that I should obtain some in this process; but the fluid that came over was merely water coloured by a minute quantity of iodine, and the orange coloured substance which remained when dissolved in water, exhibited the same acid properties as before, and combined with ammonia without affording any oxide.

The compound of iodine and iron when dissolved in water exhibited acid properties, but when the solution was distilled it yielded hydroionic acid and deposited oxide of iron, and the entire solution acted on by ammonia, afforded an olive coloured precipitate in great abundance,

1. I heated some iodine in a dry glass globe filled with sulphuretted hydrogene; there was a considerable absorption of gas, no sulphur was deposited, and a reddish brown fluid was formed, which when thrown into water rendered it strongly acid and deposited much sulphur; the water passed through a filter exhibited the properties of hydroionic acid.