262 REPORT— 1892. 



II. Molecular Volume of Iodine in Sohition. 



It is well known that the coloar of solutions of iodine varies with the 

 nature of the solvent from dark brown in the case of aqueous solution of 

 potassium iodide, through red in benzol to violet in the case of carbon 

 disulphide. 



From the colour of the last-named solution it has generally been 

 assumed that in it the iodine molecule is diatomic, as in the state of gas. 

 Within the last few years several attempts have been made to ascertain 

 what is the composition of the iodine molecule in various solvents, the 

 method employed being that of Raoult, depending on the effect of the 

 dissolved iodine on the vapour pressure of the solvent. 



The Committee have commenced the examination of this subject from 

 the standpoint of the apparent molecular volume of iodine in various 

 solvents, and considerable progress has been made with the work. 

 Aqueous potassium iodide, alcohol, ether, chloroform, benzol, xylol, and 

 carbon disulphide having been examined, it is intended to considerably 

 extend this list of solvents, and the Committee hope that they will be in 

 a position to report fally on this subject to the next meeting of the 

 Association, as they intend also to fully examine the point by the method 

 of vapour pressures. 



The Committee desire reappointment without grant. 



Report (provisional) of a Committee, consisting 0/ Professor H. E. 

 Armstroxg, Professor W. R. Dunstan, Mr. C. H. Bothamlev, 

 and Mr. W. A. Shenstone {Secretary), appointed to investigate 

 the formation of Haloids from pure Tuaterials. {Drawn up hy 

 Mr. W. A. Shenstone.) 



DuiUNG the past year two papers have been read before the Chemical 

 Society on subjects connected with the work undertaken by the Com- 

 mittee.' 



The results of further experiments with mercury and chlorine tend to 

 confirm the opinion expressed in a previous report that the interaction 

 of these two elements is greatly influenced by the presence of one or 

 more other substances, and they show that water is almost certainly one 

 of these active substances. 



Up to the present _2J?()-e chlorine has not been obtained. But W. A. 

 Shenstone and C. R. Beck have recently found that by igniting platinic 

 chloride in excess of hydrochloric acid platinous chloride may be obtained 

 in such a condition that the chlorine liberated from it by ignition in 

 vacuo is considerably more free from impurities than the prodnct of 

 igniting platinous chloride prepared in the ordinary way, and they think 

 it possible that by this method pure chlorine may perhaps ultimately be 

 obtained. 



They have also found that liquefied chlorine, which usually contains a 



' ■Platinons Chloride as a Sourne of Chlorine, Jonrn. Cliem. Soc, 1892, p. 445. 

 The Adhesion of Mercury to Glass in the Presence of Halogens, Jovr7i. Chcm. Soc, 1892, 

 p, 462. 



