406 



this communication the results of the measurements are recorded, 

 made with a series of homologous hydrocarbons and some of their 

 halogen-derivatives. With respect to the methods of purification, the 

 determination of the specific gravities, and the significance of the 

 diagrams, we can refer to the pre\'ious communications. 

 This series includes the following terms : 



Benzene; Toluene; para- Xylene ; Mesityhne; Pseudocumene ; Tri- 

 plLenyhnethane ; Cklorohenzene ; Bromohenzene ; meta-Dichlorobenzene ; 

 imra-Fluorobromobenzene; meta- Fluor otoluene; and para-Chlorotoluene. 



For the purpose of comparison wdth benzene, also Cyclohe.vane 

 Avas taken into account here ; the data relating to benzene w^ere 

 already published in a former paper '), but are repeated here once 

 more for comparison with the other hydrocarbons. The obtained 

 results are put together in tables, in the ordinary way. 



§ 2. Aromatic Hydrocarbons and some Halogenderivatives. 



1) F. M. Jaeger and M. J. Smit; F. M. Jaeger and J. Kahn ; F. M. Jaeger, 

 these Pioc, Gomm. I, II, I^^ (I'Jli,. 



