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A piece of the Charmouth fossil wood being immerged, in similar 
diluted nitric acid, a violent eifervescence 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 applied 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 touchwood, without in- 
flaming ; 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, resembled very much that 
which is yielded by the burning of pyrophori. In whichever way the 
combustion was directed, a strong bituminous odour was expe- 
rienced. A piece of the Bath fossil wood being exposed to the same 
trials, furnished exactly the same results. 
The residuum thus obtained from calcareous fossil wood, furnishes 
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 consider- 
ing its properties, we must surely conclude, not that — the more fixed, 
earthy parts, deprived of their oily, and volatile matters, had been 
combined with the lapidific matter; nor that — a substitution of stony, 
in the place of organized matter, had taken place ; nor that the lapi- 
difying 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 became much more suscep- 
