385 
notice of Liebnecht, he subjected them to the necessary examination, 
and clearly ascertained, that, although the texture was indubitably 
that of wood, the substance was an ore of iron. In the 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 hand- 
some 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 
vour recollection a phenomenon, which occurs in the neighbourhood 
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 situa- 
tions, which, from their proximity to the surface, or from rifts in the 
superincumbent strata, which admit a communication with the ex- 
ternal air, the formation of these various kinds of specimens 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, permeating every more 
solid part, cannot but be affected by the strong reductive powers, 
possessed by those principles of which the bitumen is constituted, 
VOIi. I. ^ ® 
