1876.] Specific Volumes of Liquids. 307 



be confirmed by Billet's observations of the specific gravities of liquid 

 iodine at various temperatures. His results are* : — 



Temperature . . 107°*0 lll°-7 124°-3 133°-5 151°-0 170°-0 

 Specific gravity 4-004 3-988 3-944 3-918 3-866 3-796 



If these numbers be plotted down and the curve prolonged to the 

 boiling-point of iodine, we find that the specific gravity of iodine at this 

 temperature is 3*780 • hence the specific volume of iodine (I) 



126-85 _ „„, 

 = 3-W- 335 - 



If now this value be added to that of chlorine, as given by Kopp, we 

 get a result identical with the observed volume of iodine monochloride — 



33-5 + 22-8 = 56-3. 



If we subtract the specific volumes of C 2 H 4 , as calculated by the aid 

 of Kopp's values (C=ll, 11=5*5, C 2 H 4 =44), from the specific volumes 

 of ethene bromide and ethene chloriodide, we obtain numbers which are 

 nearly equal to the specific volumes of bromine and iodine chloride re- 

 spectively : — 



97-30 _ 44 = 53-30. 

 101*27 - 44 = 57*27. 



This correspondence between the two sets of values seems to warrant the 

 conclusion that bromine and iodine chloride possess the same volume in 

 a compound which they have when in the free state. 



In order to ascertain how far this conclusion is general, I purpose to 

 determine the specific volumes of such of the C. H 10 hydrocarbons as I 

 can obtain in quantity and of sufficient purity, and also of the specific 

 volumes of their combinations with bromine. Buff has already made 

 observations upon amylene ; but a recently published investigation by 

 Elavitzky has rendered it probable that the preparation employed by Buff 

 was a mixture of isopropylethene and trimethylethene t. 



According to Flavitzky the olefine boiling at 35° is trimethylethene, 



CIA 



CH 3 / C = CH - CH = 



and not isopropylethene, 



OH\ 



CH 



>CH-CH=CE 



which boils at 25° : both hydrocarbons are derivable from fermentation 

 amyl-alcohol. 



* Jahresbericht &c. vol. viii. p. 46. 



t Ann, der Chem, u, Pharm, yol, clxxix. p. 340. 



