370 On tlie Coal-Formation 



pit crossed two beds of mineral coal, the exterior appearance 

 of which in all respects resembles that of the English or 

 Flanders coal. Its texture is foliated or laminar ; its frac- 

 ture even or conchoidal ; its colour black and shining ; the 

 division imperfectly prismatic, occasioned by contraction, is 

 often observed in it ; the offensive odour of sulpho-hydric acid 

 is developed in it by rubbing. On the surface of the laminae 

 we find a fibrous substance, friable, black with a silky lustre, 

 called by Werner, mineral charcoal {mineralische holzkohle) 

 and which is very frequently met with in the coal of other 

 countries. Pyrites disseminated throughout it, and often in- 

 visible, also minute veins of calcareous spar, are among the 

 number of its accessory elements. It is speedily kindled by 

 the flame of a torch, becomes extinguished as soon as that is 

 withdrawn, in this respect differing from the lignites. Its 

 mean density is 1-35 according to M. Matteucci. 



An immediate analysis has been given by M. Pilla, for 100 

 parts of sea-coal : 



Coke 58 to 62-00 



Sulphur 3-20 



Other volatile substances, 30'00 



Ashes 6-88 



According to mediate analysis, nearly two-thirds of the 

 sulphur was not found in it in the state of pyrites. With re- 

 gard to the coke which resulted from distillation, it is pretty 

 compact and not very vesicular ; heated in a retort, it gave out 

 a very distinct odour of sulphuric acid. 



Compared with the principal coals of England, analyses of 

 which have been given by M. Thomson, the coal of Monte 

 Bamboli nearly approaches in composition the scaly coal of 

 Glasgow, which contains, 



Carbon 55-23 



Volatile substances 35'27 



Ashes 9-50 



100-00 



To these scientific particulars, M. Pilla adds the result of 

 numerous experiments made with the view of determining 



