166 



CARBON. 



b. Graphite. (Plumbago, or Black Lead.) 



Note. This specimen came from Travancore ; it was presented by Dr. 

 Waring. 



6. AMORPHOUS. 



a. Anthracite. (Stone Coal, Culm.) 

 I. Jet, from Whitby. 



c. Glance coal. (Metallic Carbon.) 



Note. This kind of carbon is deposited on the inside of gas retorts. 



* d. Glance coal, deposited on a burnt whisp of straw. 



Note. This specimen was deposited from a jet of coal gas at a high 

 temperature in a coke oven. 



* e. Boghead coal. (T.orbanite, Torbane Hill Mineral.) 



Note. This, specimen was presented by Professor Attfield. It bears 

 the impression of a Sigillaria. It is a specimen of the mineral from 

 which paraffin oil was first obtained for commercial purposes. An ana- 

 lysis of this specimen by Prof. Attfield, yielded 36 per cent, of crude paraf- 

 fin oil. 



/. Brown coal. (Lignite.) 



Note. This specimen came from Germany. It was presented by Prof. 

 Attfield. According to his analysis, it yields by distillation paraffin oil 

 at the rate of 60 gallons per ton. 



The term lignite is sometimes improperly applied to brown coal. 

 Strictly speaking, lignite is intermediate between wood and brown coal, 

 being distinguished from all varieties of coal by yielding acetic acid and 

 acetate of ammonium, instead of an ammoniacal liquor. See Ure, Diet. 

 Mines, vol. ii., p. 870 ; vol. i., p. 497. 



g. Wood charcoal, from willow wood. 

 Ditto, from acacia wood. 



Note. These specimens illustrate the kind of wood charcoal used for 

 medicinal purposes, for which woods containing a small percentage of 

 mineral matter are necessary. 



h. Animal charcoal. (Bone Black, Carbo Animalis, B.P.) 

 i. Ditto, purified. (Carlo Animalis Purificatus, B.P.) 



7. BISULPHIDE. C S 2 . (Carbonic Disulphide, Sulpho- carbonic Acid.) 



a. Commercial specimen. 



b. Purified by digestion with copper filings. 



c. Purified, and free from disagreeable odour. 



8. DICHLORIDE. C C1 4 . (Tetrachloride of Carbon, Bichloride of Carbon, 



Carbonic Chloride, Perchlorinated Chloride of Methyl, Per- 



chloroformene.) 



a. Pure. 



