DECOMPOSITION OF WOOD, COAL, ETC. 347 



dead trees which have been in contact with water, is produced 

 in the way just mentioned. 



An analysis of wood of this kind, obtained from the interior 

 of the trunk of an oak, yielded, after having been dried at 212 Q , 



10000 100-00 



Now, on comparing the proportions obtained from these num- 

 bers with the composition of oak wood, according to the analysis 

 of Gay-Lussac and Thenard, it is immediately perceived that a 

 certain quantity of carbon has been separated from the constitu- 

 ents of wood, whilst the hydrogen is, on the contrary, increased. 

 The numbers obtained by the analysis correspond very nearly to 

 the formula C 33 H 2 7 O a4 .* 



The elements of water have, therefore, along with a certain 

 amount of oxygen from the air, become united with the wood, 

 whilst carl>oiiic acid is separated from it. 



If the elements of 5 atoms of water and 3 atoms of oxygen be 

 added to the composition of the woody fibre of the oak, and three 

 atoms of .carbonic acid deducted, the exact formula for white 

 mouldered wood is obtained. 



Wood - 



i"o this add 5 atoms of water 



3 atoms of oxygen - 



Subtract from this 3 atoms carbonic acid C 



The process of mouldering is, therefore, one of purification 

 and decay, proceeding simultaneously, in which the oxygen of 



• The calculation from this formula gives in 100 parts 479 carbon, 6*1 

 hydrogen, and 46 oxygen. 



