iigures found for density and refVaetion. These are for the naplilene : 

 ^/^^^^ = 0.7488 and ?ii>'-^-^ =r 1.4096 '), hence, mnch smaller than 

 that of cycio-hexene. 



Now, the densities found by ns are certainly somewhat below the 

 calculated ones, bur on the other hand the indices of refraction are 

 somewhat higher. Moreover, the product freed from benzene by 

 nitration had almost the true solidifying point of cyclo-hexane whereas 

 this suffers a very strong depression by the presence of admixtures'''). 

 Hence, after the nitration, these cannot have been present in quantities 

 exceeding 1 "/o- 



SUMMARY. 



1. Cyclo-hexene at 180° and ordinary pressure is metastable in 

 regard to the cori-esponding mixture of benzene and cyclo-hexane." 



2. Cyclo-hexane at 300° and ordinary pressui-e is metastable in 

 regard to the corresponding mixture of benzene and hydrogen 

 (Zbuinsky). Six cyclo-combined carbon atoms are then trivalent in 

 regard to the hydrogen. 



3. Cyclo-hexene at 180° and ordijiary pressure is metastable in 

 regard to rhe corresponding mixture of benzene and hydrogen. 



4. Cyclo-hexene is more strongly .wp^rsaturated with hydrogen 

 than cyclo-hexane. 



5. Probably, methylcyclo-pentane at 280° and under pressure is 

 more stable than the corresponding mixture of benzene and hydrogen 

 or cyclo-hexane. 



6. Nickel is, in the first place, a hydrogen activator; the carbon 

 activation becomes only considerable at 240°; at 180° this latter action 

 in regard to the first may be neglected. 



7. Palladiuni is an excellent hydrogen activator, the carbon activa- 

 tion may still be neglected at 300° (Zelinsky). 



8. Iodine at 280° and under pressure is presumably a strong 

 hydrogen and a feeble carbon activator "'). 



1) Zelinsky. B. 35, 2684-86 (1902). 



~) Masgarelli states a molecular depression of about 200 (Atti R [5] 16 I 924 

 (1907); Ihi' value we obtained also in the determination of the melting line of 

 the system CgHg — CcHij which consequently takes a very asymmetric course. 



8) See Pat. Kl-o 250236 3/8 1910, Zentr. Bl. 1912 II 1084. 



