214 Mr. Woods on the Anthracite Coal of South Wales. 



gramme is capable of raising 76*54 kilogrammes of water 

 (quere from 32°) to the boiling point, or of evaporating 11 '55 

 kilogrammes. All the samples of coal placed in my hands 

 were of a brilliant black, very compact, and of a lamellar 

 structure ; the cross fracture rough and uneven ; they do not 

 soil the fingers, and break easily under the hammer; the 

 hardness is nevertheless considerable, and it is difficult so to 

 reduce it to powder as to destroy its brilliancy. 



The double carbonate of lime and iron occurs between the 

 laminae of this coal, and sometimes agglomerations of carbo- 

 naceous matter possessing the appearance, lightness and fria- 

 bility of wood charcoal. 



The specific gravity of this coal is 1 *27 ; it burns in the 

 furnace without flame; a small quantity reduced to powder 

 consumes slowly without inflaming; ignited masses do not 

 lose their form, but when separately exposed to the air become 

 extinguished, whereas in mass the combustion succeeds well in 

 the reverbatory furnace. 



I incinerated some of this coal reduced to powder in a 

 muffle furnace charged with the same coal, and beginning with 

 a stratum of lighted charcoal: the combustion continued for 

 five hours, while every part of the interior of the furnace was 

 incandescent. 



The residue of this incineration upon a small scale, consists 

 of slightly ferruginous and calcareous ashes ; that of combus- 

 tion on the large scale is similar, but mixed with some small 

 pieces of coal having suffered incipient exfoliation. The 

 ready combustion in mass is undoubtedly to be attributed to 

 a slight separation of the laminae of the coal produced by the 

 high temperature, and to the emission of a gas*. 



The quantity of gas which this coal is capable of supplying 

 in close vessels has been found to be 24 litres for 100 grammes 

 of coal, equivalent to 240 litres for a kilogramme. It will be 

 seen that these results approach those obtained on the large 

 scale in gas-works, where that quantity yields 180, 200, and 

 250 litres of gas ; unfortunately the gas produced from this 

 anthracite does not give more light than pure hydrogen; it is 

 now well known that illuminating power may be communi- 

 cated to hydrogen gas by causing it to circulate in reservoirs 

 over the surface of oil of schist or of tar. 



From what has been stated, it is evident that coal having 

 a uniform character similar to that which 1 have analysed, 

 would be much in demand on account of its remarkable 

 purity, both for domestic consumption and for blast furnaces, 



* I do not exactly comprehend how this separation of the lamina? pro- 

 motes combustion. I should have thought its tendency would have been 

 to choke and check the fire. — S. W. 





