Inqiiiries relative to the Structure of Wood. 463 



The six following, made with different species of 

 wood, were so uniformly alike in their results, that I 

 was much surprised. 



One hundred parts (10 grammes) of the six follow- 

 ing kinds of wood, in thin shavings, and thoroughly 

 dried, were carbonized at one time in the stove, in glass 

 vases, well closed with flat glass covers. As the heat 

 was managed with great care, in order to determine 

 with precision, from the weight of the vases, the mo- 

 ment when the operation was finished, the experiment 

 occupied four days and as many nights. When the 

 vases with their contents ceased to lose weight, the pro- 

 cess was stopped, and the charcoal was weighed while 

 still hot. 



The following were the results : 



100 parts in weight of 



dry wood 

 gave in dry charcoal. 



The medium term of the results of these six experi- 

 ments gives 43.33 parts of charcoal in 100 parts of dry 

 wood ; and as they were made with woods differing 

 considerably in their apparent weight, their hardness, 

 and other distinctive physical characters, we may con- 

 clude, from the great similarity of the results of these 

 experiments, that none of the circumstances from which 

 the woods derive their particular characters have any 

 material influence upon the quantities of charcoal they 

 are capable of yielding ; and hence we may deduce that 

 the ligneous substance or seerwood, if not the same in 

 all, is at least composed of identical substances. 



