410 



sense, in which it has been already applied to fossil wood, into the 

 interstices of which clay has freely penetrated. 



On putting a piece of this wood, impregnated with lime, into 

 diluted nitric acid, the same effects were produced as when other 

 calcareous fossil wood was subjected to the same experiment. The 

 carbonate of lime was decomposed, and, on the earth being re- 

 moved, the fibres of the wood were found in a loose and detached 

 state; of a dark brown colour, and burning with a white flame, and 

 a bituminous odour, on being applied to the flame of a candle. 



I have, in a former Letter, remarked that the process of bitumi- 

 nization seems to be inimical to animal life ; and that, after any 

 vegetable substance has been exposed to its influence, it appears to 

 be no longer fitted to become the aliment of any animal. Nature 

 having now destined this matter to undergo a peculiar chemical 

 change, the first step is to prevent its being subject to any other 

 kind of alteration, which might interfere with this arrangement. 

 This is confirmed by the appearance of these specimens, in which 

 the wood has evidently been exposed to the process of bituminiza- 

 tion, since it had been subjected to the ravages of the teredines*, 

 These pieces of wood, I, therefore, conjecture to have lain in the 

 sea, subjected to the devastating labours of these animals, until, 

 by some of those changes, of which a former letter has aimed to 

 give, at least, some slight notion, they became overwhelmed with 

 earth ; and that, while thus buried, and secluded from the atmos- 

 phere, they passed into the bituminous fermentation ; and after- 

 wards, from the infiltration of certain lapidific juices, obtained their 

 present form of existence*. 



* It seems to be deserving of trial, whether slightly bituminized wood might not be ad- 

 vantageously employed for ship's bottoms, and for other purposes, in which the ravages 

 of the ship-worm are particularly required to be guarded against. It even seems desirable 

 that it shoui i be ascertained, how far wood which has been involved in hay whilst forming 

 in the rick, would be protected against these animals. 



