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RJSSINITE xYLoiDEof Hauy In these the characters of wood are 

 so distinctly marked, that no one can entertain the least doubt of 

 their having originated from wood. The resinous, or waxy lustre, 

 which they manifest, has been already examined, as to the degree 

 of evidence it affords of the wood having existed in a bituminous 

 state. Their fracture, perhaps, serves also to further prove their 

 ligneous origin ; since although this is in general conchoidal, it will 

 frequently, when longitudinal, be splintery, and even fibrous, in the 

 direction of the fibres of wood. Their colours vary very much, 

 from milk white, through all the shades of brown and yellow, to 

 green, red, and black; but their most frequent colours are those, 

 which approach so near to that of the original wood, blended with 

 that of common resin, as to corroborate strongly the idea of the 

 wood having been softened down, into a resiniform substance, pre- 

 vious to its impregnation with silex. Their transparency, which is 

 sometimes such as to admit light through them freely, and even,, 

 when in thin slices, such as to allow objects to be seen through 

 them, is a circumstance which it is impossible to account for in 

 any other way so well as by supposing the wood to have been ren- 

 dered a clear bitumen during its first change. A specimen of this 

 kind of pitch-stone, or fossil wood, possessing in its internal part a 

 considerable degree of transparency, whilst the external part bears 

 the appearance of recent wood, is figured in Plate III. Fig. 8. 

 These fossil woods are also characterized by a circumstance which 

 has excited the admiration of mineralogists, and which at the same 

 time seems to manifest the intermixture of some substance with the 

 silex which does not seem to exist in any other stone of the silicious 

 genus although they appear, from their peculiar kind of lustre, to 

 be little harder than resin, and sometimes give fire with steel with 

 difficulty, they yet are more difficult to be scratched than many 

 that do this more freely. 



The combination of bitumen and silex, in these specimens of 



