292 



rounded, and enveloped in such various fantastic forms, that the 

 most expert artist could hardly have depicted them all. Lastly, 

 some were only partly pyritous, and others were formed entirely by 

 a very hard and heavy pyrites of a silver hue. By a reference to 

 Plate VI. Fig. 1, 23,27, and 29 a more correct idea may, perhaps, 

 be obtained of the forms which Piilingeii here describes. 



o 



In a former part of our inquiry, it was endeavoured to be proved, 

 that bituminization is the first essential process, in the mineralization 

 of vegetable matter; and now, I trust, it has been shown, that the 

 further mineralization, the metallization of vegetable matter which 

 has been thus bitnminized, is very likely to result from its union 

 with certain substances which are, or have been, present, in a state 

 of fluidity, in most subterranean parts of this globe. Reflection on 

 the changes which must take place in wood softened by the bitu- 

 minous fermentation, and permeated thoroughly by a solution of 

 iron in the sulphuric, or sulphurous, acid, will enable us to form a 

 more correct judgment on this point. These changes would not 

 much differ from the following. The abundance of hydrogen, 

 possessed by the bituminous wood, would occasion a deoxydation 

 of the metal, and of the sulphur, which had been carried into 

 contact with it, in a state of solution ; the greatest part of the car- 

 bonaneous matter of the wood remaining. Repeated minute ex- 

 amination of metallized woods have clearly shown to me, that their 

 structure is exactly agreeable to this supposed mode of their for- 

 mation. The circles and striae, which give the characteristic ap- 

 pearance of wood to these substances, are evidenly formed of the 

 ligneous fibres converted to charcoal, whilst all the intermediate 

 spaces are filled with the brilliant metallic matter. 



According to the hypothesis, here endeavoured to be supported, 

 the vegetable substance, at first, suffers a thorough penetration with 

 moisture ; it then is submitted to the influence of the process of 

 bituminization, by which it passes through various degrees of soft- 



