3? 8 



A piece of the Charmouth fossil wood being immerged, in similar 

 diluted nitric acid, a violent effervescence took place, during which 

 some light particles were detached ; and at the end of twelve hours> 

 the effervescence having ceased, the fluid was poured off, when a 

 dark brown, friable, but coherent mass, bearing every appearance 

 of bituminous wood, was found. This being repeatedly washed, 

 and afterwards dried, was exceedingly light and brittle, but still 

 retained the form and colour of bituminized wood. On being ap- 

 plied within an eighth of an inch of the flame of a candle, or of 

 any substance heated red-hot, it caught fire, and burnt like touch- 

 wood, without inflaming ; but., if brought into contact with the 

 flame, it yielded a white flame. The appearance it made, whilst 

 burning, from the spread of the fire through its substance, from its 

 phosphoric glow, and from its brilliant white lambent flame, resem- 

 bled very much that which is yielded by the burning of pyrophori. 

 In whichever way the combustion was directed, a strong bituminous 

 odour was experienced. A piece of the Bath fossil wood being ex- 

 posed to the same trials, furnished exactly the same results. 



The residuum thus obtained from calcareous fossil wood, fur- 

 nishes us with considerable information, not only respecting the 

 state in which it existed, previous to its petrifaction, but also in 

 regard to the mode in which this process has been accomplished. 

 After considering its properties, we must surely conclude, not that 

 the more fixed, earthy parts, deprived of their oily, and volatile mat- 

 ters, had been combined with the lapidiftc matter; nor that a SUB- 

 STITUTION of stony, in the place of organized matter* had taken, 

 place; nor that the lapidifying matter had been injected, whilst 

 melted by heat, into the interstices of the combustible substance : but, 

 we must rather infer, from the high degree of combustibility, and 

 even of inflammability, possessed by this residuum; and by the 

 form it retains, that the original woody substance, previous to its 

 envelopement with stony matter, underwent a change by which it 



