365 Ftirtlier Experimenis and Olservattons on Iodine. 



deposited much sulphur ; the water passed through a filter ex- 

 hibited the properties of hvdroionic acid. ' 



It is evident from this e:\pefimcnt, that sulphur, iodine^ and 

 hydrogen, are capable of forming a triple coin])ound. 



2. 1 sublimed some iodine in dry defiant gas ; a little of a 

 reddi?h-brown fluid was formed, but the greatest part of the 

 iodine crystallized on the sides of the vessel in whicli tlie ex- 

 periment was made. By repeating the process several times, 

 more of the fluid was formed. It was volatile at a moderate 

 heat, and gave a yellow tint to water, but did not render it acid, 

 there vv-as a very slight absorption of the gas. 



3. Iodine subhmed in nitrous gas effected no change in it. 



4. When iodine was exposed to carbonic oxide it underwetit 

 no change, it was repeatedly, sublimed in it in common day-light 

 without u'.idergoing the sliglitest alteration. 



When the violet gas was formed by heating iodine in carbonic 

 oxide, and the vessel exposed for some time to the direct solar 

 rays, a small quantity of a limpid fluid which had an acrid taste 

 foraged in the vessel. An accident prevented me from ascer- 

 taining if any gas had been absorbed, but it seems probable from 

 this result that, like chlorine, iodine may be combined with car- 

 bonic oxide by the agency of light. 



5. On the Mode rf detecting Iodine in Comlinalions, and on 

 certain Properties of its Compound ivitli Sodium. 



1. I have examined many of the marine productions of the 

 Mediterranean, with th^e view of determining whether they con- 

 tained iodine. Ti»e ashes of ihe fuci and ulvie of this sea aiford 

 it in much ^smaller quantities than the sel de varec, and in a 

 very' few cases only have I been able to obtain evidences of its 

 existence in them. 



2. M. Berard \vas so good as to order a considerable quan- 

 tity of the species of ulva, which abounds on the coast of Lan- 

 giiedoc, to be burnt for me at his laboratory at Montpellier, 

 The ashes consisted for the most part of common salt, but a 

 small quantity of alkaline lixivium which was obtained from 

 them, afforded a red fluid when acted ui)on by sul})huric acid, 

 and a similar colour I found was produced, when a solution of 

 subcarbonate of soda an<l couuuon salt, containing a minute 

 quantity of llie compound of sodium aud iodine, was treated in 

 the same monner by the acid. 



3. One of the best tests of the presence of a very minute 

 quantity of iocUne in compounds, is their action upon silver. 

 Water when it contains less tlian t uVir P'^^^ ^f J^s weight of the 

 double or triple alkaline compounds of iodine tHrni-ihes polished 

 iilver. The 



