MODE III. COAL. 5() 



Some select observations concerning coal may 

 be added from various authors. 



By Mr. Kirwan's experiments coal commonly 

 consists of about 60 carbon and 40 bitumen*. 



Though coal has never been found crystallised, structure, 

 it seems to split into regular cubes; and another 

 singularity in its structure has recently been ob- 

 served, that between the layers of a bright bitu- 

 minous appearance there are thin plates of a 

 velvety lustre, bearing a strict resemblance to 

 charcoal. Coal sometimes contains in little ca- 

 vities, crystals of calcareous spar, perhaps infil- 

 trated from incumbent limestone. These crys- 

 tals, towards their summits, present little black 

 zones, arising from the coaly impregnation. Ga- M 5 

 lena, or sulphate of lead, is also found in the coal 

 of Buckinghamshire. Pyrites are common in 

 most kinds of coal ; and, perhaps, the beautiful 

 iridescent illinitions, which in some rare in- 



informs us that beds of coal are there found at an elevation of 13,200 

 feet perpendicular. When the ocean reached such a height, there 

 would be above its level but a small number of islands scattered 

 over the face of the globe ; and it is not any how seen, how the 

 small quantity of vegetables, which had been accidentally brought 

 from these summits of mountains, into this immense ocean, could 

 have formed the thinnest bed of coal, or even of simple turf." Is not 

 this coal of Santa-Fe anthracite ? 



* Bitumen long retains its properties. That found on the bricks 

 of Babylon, where it was used as a mortar or cement, still burns, as 

 Mr. Parkinson observed, with a strong bituminous scent. 



