1876.] Specific Volumes of Liquids. 305 



iodine monochloride to ethene, matters being so arranged that a large 

 excess of the hydrocarbon was present during the reaction. The result 

 was altogether different from what I anticipated. When the two substances 

 are brought together, nearly the whole of the iodine is set free, and 

 Dutch liquid is formed, only a very small quantity of the chloriodide 

 being produced : I varied the conditions of the experiment in several 

 ways, but with invariably the same result. I have since found that 

 Greuther has made the same observation*. It is remarkable that the 

 presence of water should so completely modify the reaction. It must be 

 remembered, however, that in an aqueous solution of iodine chloride 

 there is always more or less free hydrochloric acid and iodic acid, a por- 

 tion of the iodine chloride being decomposed in accordance with the 

 equation 



51 CI + 3H 2 = 5HC1 + HI0 3 + 2I a , 



the extent of the decomposition being probably dependent on the ratio 

 of the products of decomposition to the compound still undecomposed. 

 This supposition is rendered probable by the observations of Hannay, 

 that, on filtering the solution from the iodine, a further precipitation 

 gradually occurs; and that on mixing an aqueous solution of iodine 

 chloride with carbon bisulphide, which dissolves the iodine as it separates 

 out, the whole of the compound is gradually decomposed, nothing but 

 iodic and hydrochloric acids being left in the water. 



Dr. Maxwell Simpson kindly sent me a sample of ethene chloriodide 

 prepared by the process above described, with the direction that in order 

 to render it quite pure it was merely necessary to wash it with dilute 

 potash and dry it. After being dried over phosphorus pentoxide it 

 boiled almost completely between 139°*1 and 140°*1. Barometer 759*3 

 millims.; n=50°, 2' = 110°; corrected and reduced boiling-point 140 o, l. 



Two observations of specific gravity gave, (1) 2*13363 at 15°*28 and 

 (2) 2*13329 at 15°*43, compared with water at 4°. Eeduced to 0°, the 

 specific gravity becomes (1) 2*16440 and (2) 2*16437. Mean 2*16439, 

 compared with water at 4°. 



Ethene chloriodide solidifies to a white crystalline mass in a mixture 

 of snow and hydrochloric acid. 



Other observers have found : — 



Boiling-point. Barometer. Specific 



millims. gravity. 



Simpson 140-143 .. 2*151 at 



Maumene 146 753 2*39 „ 20 



Observations with the dilatometer have led to the formula 



Y = 1 + 0*000 936 917 Qt + 0*000 000 415 129 * 2 



+ 0*000 000 004 501 4 1 3 , 



which represents with sufficient accuracy the expansion of ethene chlor- 

 * Jahresbericht &c. vol. xv. p. 491. 



