1876.] Specific Volumes of Liquids. 301 



sulphurous acid solution, precipitating the hydrochloric and hydriodic acids 

 by silver nitrate, and digesting the mixed salts with strong nitric acid. 



I. Amount of 1 CI taken 1-2482 gram. 



II. „ „ „ .... 0-5668 „ 



I. Silver salts obtained 2-9095 grams. 



II. „ „ „ 1-3223 gram. 



From these data, using Stas's numbers for the atomic weights of chlorine, 

 iodine, and silver (01=35-46,1=126-85, Ag = 107*93), we get, by means 

 of the equation 



W^-^ + Cl + Ag, 



(in which W = the weight of mixed silver salts, and x and y respectively 

 the amount of iodine and chlorine contained therein), the following results 

 expressed in percentages : — 



I. II. Calculated. 



Chlorine 21-86 21-98 21-85 



Iodine 78-14 78-02 78-15 



100-00 100-00 100-00 



Iodine monochloride, as a liquid, bears a marked resemblance to bro- 

 mine. Although when solidified it melts at a temperature as high as 

 24°-2 (according to my observations), it not unfrequently remains liquid 

 for many weeks after distillation, and may be cooled to below 0° without 

 congealing. In a freezing-mixture of ice and salt it readily solidifies to 

 a dark reddish-brown crystalline mass. Long-continued shaking at 

 ordinary temperatures occasionally brings about its solidification. A 

 quantity of iodine monochloride which had been liquid for months 

 crystallized in long prisms when subjected to the vibration of a railway- 

 carriage. Mr. J. B. Hannay has already published a number of curious 

 observations on the solidification of this compound *. 



The specific gravity of iodine monochloride at 17°'95 is 3-12988, com- 

 pared with water at 4° • at 0° its specific gravity is 3*18223, compared 

 with water at 4°. 



Other observers have found for the melting- and boiling-points of 

 this compound : — 



Boiling-point. Melting-point. 



Schutzenberger 100°-102° 30° 



Trapp .... 25° 



Hannay 100°-102° 24°-7 



Observations with the dilatometer have led me to the following formula 

 * Journ. Chem. Soc. 1873, p. 815. 



