988 Mr. Gervaise Le Bas on the 



The following compound is also interesting in this con- 

 nexion: — 



Acetylene Dibromide C 2 H 2 Br 2 . 



M.Y 91-3 XM.V a 93-0 if Br = 28-0 



A... -1-7 



C 2 H 4 Br 2 givesA-3-l. 



We must thus suppose that the formula is 



CH— Bi- 

 ll 



ii ' 

 CH— Br 



but that the olefin linking diminishes the value of A. 



The Effect of Chlorinating Benzene. 



One aspect of the work in this section is the successive 

 chlorination of the Paraffins. 



Take for instance ethane C 2 H 6 . By successive chlori- 

 nation we obtain the compounds 



CH 3 . CH 2 C1, CH 3 . CHC1 2 , CH 3 . CC1 3 

 CH 2 C1.CC1 3 , CHCI0.CCI3, CC1 3 .CC1 3 



The result is to show that only the a compounds are 

 normal ; the /5 compounds are marked by a contraction in 

 volume which is the result, it is contended, of the formation 

 of Partial Rings — or, perhaps, from another point of view 

 Temporary Rings. 



The question now is, what may be the effect of succes- 

 sively chlorinating benzene C 6 H 6 ? We are able to answer 

 this question, to some extent at any rate, owing to the work 

 of Jungfleisch (Jahresberichte, xx. p. 36, xxi. p. 352). 



Monochlorbenzene. C 6 H 5 C1. 



(Unsymmetrical or Odd). M.Y. 114'6. 



B.P. 132°-0. 



Cl=C 6 H 5 Cl-G 6 H 5 =114-6-92-8=21-8. 



1 : 4 Dichlorhenzene. C 6 H 4 C1 2 . 



CI 



(Symmetrical or Even). M.Y. 130*9. 



B.P. 172°-0. 



Cl 2 =O s H 4 Cl 2 -C 6 H 4 =130-9-89-6=41-3. 



