notice of Liebnecht, he subjected them to the necessary examina- 

 tion and clearly ascertained, that, although the texture was indu- 

 bitably that of wood, the substance was an ere of iron. In tLe 

 iron mines of Montrouge, beyond Martis-see, the greatest quantity 

 of the iron ore, which is dug from the depth of from seven to eight 

 toises, is said to be wood of the birch, and of the beech tree, changed 

 to iron, A similar ore is also dug at Orbisau, in Bohemia ; and very 

 handsome specimens of this kind of wood are found, according to 

 Bertrand, in the canton of Berne, in Switzerland. Near the lake 

 Langelmo, in Finland, parts of trees are said to be found, which 

 appear to have suffered a conversion into iron. 



Almost every specimen of wood, mineralized by iron, except those 

 of the pyritous kind, seem to owe their change to the introduction 

 of particles of the red oxide of iron, or that oxide which precipi- 

 tates with an excess of its base, from a solution of the oxy-sulphate 

 of iron. What is here said, will be better understood, by calling to 

 your recollection a phenomenon, which occurs in the neighbour- 

 hood of springs impregnated with iron, held in solution in the 

 sulphuric acid. In every little puddle or swamp, in which this kind 

 of mineral water is collected, a yellow precipitate is discoverable, 

 which has been deposited from a yellow crust which is continually 

 forming on the surface of the water. On a similar deposition of 

 oxide, in situations, which, from their proximity to the surface ; or 

 from rifts in the superincumbent strata, which admit a communication 

 with the external air, the formation of these various kinds of speci- 

 mens depends. An egress is here allowed to the separated gaseous 

 matter, on the confinement of which the formation of pyrites and 

 coal, &c. seem to depend ; a constant separation of red oxide, or of 

 oxy-carbonated iron, goes on, which fills every interstice of the 

 loose bituminous wood; whilst the dissolved sulphated iron, per- 

 meating every more solid part, cannot but be affected by the strong 

 reductive powers, possessed by those principles of which the bitumen 



VOL. I. 3D 



