206 



Hydrocarbons. 



a. White slender acicular crystals. 



394. CAOUTCHOUCINE. 



a. Brownish oily liquid. 



Note. This liquid, according to Greville Williams, is a mixture of the 

 two polymeric hydrocarbons caoutchin, C 10 Hj 6 and isoprene, C 5 H 8 . 



395. COOROONGITE. (Mineral Caoutchouc). 



a. Blackish, slightly elastic, solid. 



BENZENE SERIES. H n C 2n _ 6 . 



a. Coal tar. 



b. Wood tar. (Stockholm Tar.) 



c. Light oil of tar, sp. gr. 0'945. 



d. Heavy oil of tar, sp. gr. 1'002. 



Note. Specimen b and c were prepared by Professor Eedwood. 



e. Eblanin. C 5 H 8 2 . (Pyroxanthin.) 



Note. This specimen was prepared by the action of hydrate of potas- 

 sium upon heavy oil of wood tar. See Watts, Diet. Chem., vol. iv., 

 p. 776. 



/. Pitch. 



g. Asphalt, from an Egyptian mummy. 



Note. The above specimens, with the exception of Eblanin, are inde- 

 finite mixtures of various hydrocarbons belonging chiefly to the aromatic 

 group represented by the formula Cn H an - 6. The asphalt obtained from 

 mummies is used by artists as a brown water-colour. This specimen was 

 presented by Messrs. Hearon, Squire, and Francis. 



396. BENZENE. C 6 H 6 . (Bicarburet of Hydrogen, Benzole, Benzine.) 



a. Impure, from coal-tar oil. 



b. Purified, by crystallization at 1 Fahr. 



397. NITROBENZENE. C 6 H 5 (N0 2 ). (Oil of Mirbane, Artificial Oil 



of Almonds.) 



a. Yellowish oily liquid, crude. 

 6. Purified. 



Note. For means of distinguishing this liquid from essential oil of 

 almonds, see Attfteld, Chemistry. 



398. DlNITEO-BENZENE. Cg H 4 (N0 2 ) 2 . 



a. In acicular crystals. 



Note. In this specimen the crystals, which were originally white, 

 have become of a brown colour. 



399. TOLUENE. C 7 H 8 . (Toluol, Methyl-Benzene, Hydride of Benzyl, 



Benzoene Dracyl, Hydride of Tolyl or Toluenyl.) 

 a. Volatile colourless liquid. 



400. XTLENE. C 8 H 10 . (Xylol, Dimethyl-Benzene.) 



a. Colourless volatile liquid. 

 Note. For uses, etc., see P. J. [3] , vol. ii., p. 625. 



