MANUFACTUKE OF WOOD- VINEGAR. 219 



Decomposition of Wood at a Higher Temperature. 



All organic bodies, except those which sublime without change, 

 are decomposed when exposed to heat in closed vessels, their con- 

 stituents interchanging with one another and forming new com- 

 pounds, which are of sufficient stability to resist the particular 

 temperature employed. Thus, the elementary components of 

 wood, after a certain amount of heat is applied, arrange them- 

 selves into combinations quite distinct from those in which they 

 originally were. Some of them are gaseous, but at moderate 

 temperatures by far the greater part are liquid, the quantity of 

 the latter depending entirely upon the greater or less degree of 

 heat applied in this distillation. 



The main cause of decomposition of such an organic body as 

 wood by heat is that the strong affinity of its contained oxygen 

 for carbon and hydrogen and the comparatively greater stability 

 of the more simple compounds of these bodies, cause their for- 

 mation the moment there is a sufficient amount of commo- 

 tion amongst the atoms of the original body to allow them to 

 commingle freely. Heat sets up the necessary vibration, and 

 those compounds are at once formed which can resist without 

 rupture of their constituents from each other, the multitude or 

 amplitude of the vibrations corresponding to the temperature at 

 which they are evolved. 



As a general rule, those bodies containing much oxygen are 

 decomposed at comparatively low temperatures. Acetic acid is 

 an exception ; a dull red heat does not cause its constituents to fly 

 sufficiently apart from each other to cause their total separation, 

 and the compound, therefore, remains unchanged. To this cir- 

 cumstance is due the large amount of acetic acid which is pro- 

 duced during the destructive distillation of wood. As previously 

 stated, the composition of cellulose is C 6 H 10 O 5 . The hydrogen 

 and oxygen being in the proportions to form water, the with- 

 drawal of carbon would form acetic acid thus : 2C 6 A 10 O 3 2C 

 = 4C 2 H 4 O 2 . As might be anticipated, acetic acid is amongst 

 the earliest and most abundant products of the distillation of 

 wood, and, being volatile, escapes decomposition at the higher 

 temperatures employed later. As the distillation progresses, 



