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, 2/, and 29, a more correct idea may, perhaps, 
be obtained of the forms which Pillingen here describes. 
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 bituminized,^ 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 carbonaceous matter of 
the wood remaining. Repeated minute examination of metallized 
woods have clearly shown to me, that their structure is exactly 
agreeable to this supposed mode of their formation. The circles and 
striae, which give the characteristic appearance of wood to these 
substances, are evidently 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 j it then is submitted to the influence of the process of 
bituminization, by which it passes through various degrees of soft- 
