CHEMISTRY OF ITS DEATH. 99 



the earth, and can no longer be distinguished 

 therefrom. How has this great change been 

 effected ? By what means has the hard and un- 

 yielding woody fibre of this giant tree been 

 broken up, and left a mass of powder? Che- 

 mistry gives the reply, and informs us, that it is 

 by successive chemical decompositions, that the 

 loftiest inhabitant of the woods has fallen, and 

 entered the common home of all living things, 

 where the great and the small, even among 

 plants, rest together. 



When woody fibre is moistened, and freely 

 exposed to the action of the atmosphere, it im- 

 mediately begins to undergo chemical decompo- 

 sition. There is an interchange of ingredients 

 between it and the air. There is also a certain 

 amount of heat evolved. The fibre alters its 

 external characters, changes colour, and loses 

 tenacity : in common language, it is said to be 

 "rotting." The process goes ,on, the colour 

 deepens, until at length it becomes brown, and 

 the mass is so friable as to crumble to pieces in 

 the hand. 



The chemistry of this change is not difficult. 

 The organic compounds of the tree decompose, 

 and their elements, carbon, oxygen, hydrogen, 

 and nitrogen, become re-arranged in a more 

 simple form. The hydrogen of the wood com- 

 bines with oxygen, and is gradually given off 



