OF WOODY FIBRE. 311 



of the decay of wood, with the slow combustion or 

 oxidation of bodies which contain a large quantity 

 of hydrogen. Viewed as a kind of combustion, it 

 would indeed be a very extraordinary process, if the 

 carbon combined directly with the oxygen ; for it 

 would be a combustion in which the carbon of the 

 burning body augmented constantly, instead of di- 

 minishing. Hence it is evident that it is the hy- 

 drogen which is oxidised at the expense of the 

 oxygen of the air; while the carbonic acid is 

 formed from the elements of the wood. Carbon 

 never combines at common temperatures with oxy- 

 gen, so as to form carbonic acid. 



In whatever stage of decay wood may be, its ele- 

 ments must always be capable of being represented 

 by their equivalent numbers. 



The following formula illustrates this fact with 

 great clearness : 



C36 H22'O22 oak wood, according to Gay-Lussac and Thenard.* 

 C35 H20 O20 humus from oak wood ( Meyer) .f 

 C34 HIS O18 (Dr. JVilT).% 



It is evident from these numbers that for every 

 two equivalents of hydrogen which is oxidised, two 

 atoms of oxygen and one of carbon are set free. 



Under ordinary circumstances, woody fibre re- 

 quires a very long time for its decay ; but this pro- 

 cess is of course much accelerated by an elevated 



* The calculation gives 52'5 carbon, and 47-5 water. 

 -}- The calculation gives 54 carbon and 46 water. 

 The calculation gives 56 carbon and 44 water. 



