444 Dr. Inglis's Extracts from his Prize Essay on Iodine, 



Mr. Kane of Dublin has described a third, which has not yet 

 been got in an isolated state : and I think a fourth may fairly 

 be added, for in all cases when I brought chlorine in a per- 

 fectly dry state into contact with iodine, also freed from mois- 

 ture, I found that constantly the first step in the process was 

 the liquefaction of the iodine. Now what is this but a change 

 in form of both the elements? Their characters are changed, 

 they have now assumed a new state of existence, and what 

 more, then, is necessary to constitute a chemical compound ? 

 This being the lowest state of chloridation, the dark liquid 

 compound formed may be called a subchloride of iodine. As 

 the action proceeds, more chlorine is absorbed, and the dark 

 reddish brown compound of Gay-Lussac is formed, which 

 may be called the sesquichloride ; and lastly, the perchloride, 

 or the chloriodic acid of Sir H. Davy, of an orange yellow co- 

 lour, results. * * * * 



When iodine is added to the chloride of sulphur a com- 

 pound is formed having many properties in common with 

 bromine. This artificial bromine is decomposed by galvanism, 

 whilst the true element is not. We are certain that there 

 have been abounding in the waters of the ocean from time 

 immemorial these three principles, — chlorine, sulphur, and 

 iodine ; may not, then, the slow and long-continued action of 

 these on each other in their purely nascent state, account for 

 the undecomposable nature of the natural bromine ? * ■* * 



Mr. Kemp discovered a very beautiful process for the li- 

 quefaction of sulphuretted hydrogen : he found that if dry per- 

 sulphuretted hydrogen be introduced into a liquefying-tube, 

 it slowly resolves itself into liquid protosulphuretted hydro- 

 gen, whilst sulphur in crystals is deposited. If previously 

 there has been introduced into the end of the tube iodine in 

 a dry state, then the protosulphuretted hydrogen, when it 

 comes over upon it, dissolves it rapidly, and a dark yellowish 

 brown coloured liquid results. If now to this there be added 

 the least possible proportion of water (which is accomplished 

 by a peculiar bend in the tube), instant reaction takes place, 

 sulphur is deposited, and hydriodic acid in a most condensed 

 and liquid state results. It is only necessary that a trace of 

 water be present to commence the decomposition of the former 

 brown compound, which I suppose to be the hydrosulphuret 

 of iodine ; for when this once commences, it goes on to any 

 extent, and the liquid hydriodic acid formed may be called 

 almost anhydrous. It boils by the heat of the hand like other 

 condensed gases ; it is of a yellowish colour, and resembles 

 somewhat liquefied chlorine. * * * 

 [To be continued.] 



