615 

 XXXIII. 



§ 3. If we now review the results here obtained, it will appear 

 ill lirst instance that such position-isomeric substances at the same 

 temperatures do not possess the same surface-energy in general, as 

 was formerly occasionall}' supposed. One cannot deny that the fi-^curves, 

 and especially those of the aromatic hydrocarbons, if siibstilnted by 

 halogen-atoms or nitro-groups, often closely approach each other: 

 so e.g. with 0- and m-Dinitrohenzene, wilh o-, m- and p-Chhronitro- 

 benzene; with o- and m-Bromonltrohenzene; with o- and p-Fluoro- 

 nitwbemeiii' \ and with J -2-4-, l'4:-2-,a.nA l-^-^-Dichloronitrohenzencs. 

 In tiie case of the nitrated phenols these curves deviate much more ; 

 but we must conclude this to be caused by differences of the 

 internal structure of the mentioned compounds, which are undoubtedly 

 connected with the presence of the //-atom in the OH-gvoup. F'or 

 while the mutual dilferences are rather great in the case of the 

 substituted phenols themselves, these differences will be strongly 

 (liiuinished, if e. g. in the deri\;\(ives of |)olyvaieii( phenols ani' of 



40 

 Proceciiings Royal Acitl. Amstcnlani. Vol. XVIU. 



