S 8 o Dr . Prout on the ultimate composition 
Lignin , or the woody fibre. 
Messrs. Gay Lussac and Thenard first showed that the 
hydrogen and oxygen in this principle exist in it in the pro- 
portions in which they form water, a result fully confirmed 
by my experiments. The variety of forms in which lignin 
occurs in different woods is so great, that an examination of 
them all would be quite out of the question ; I therefore 
selected two, viz. the woods of the Box and Willow , which 
appeared to present the greatest contrast ; the one being 
among the densest, the other the lightest of the woods. 
These were both treated exactly in the same manner, that is 
to say, they were first reduced to the form of a coarse powder 
by rasping, then well pulverized in a Wedgwood mortar, 
and afterwards sifted. Being by these means reduced to the 
form of impalpable powders, they were boiled in repeated 
portions of distilled water till that fluid came off unchanged : 
a tedious process, requiring several days to accomplish per- 
fectly. After this they were similarly treated with alcohol, 
and finally again with distilled water. They were now ex- 
posed to the atmosphere, when in a dry and favourable state ; 
and when they ceased to lose weight were submitted to ana- 
lysis, and found to consist of (abstracting foreign matters) 
Box. Willow. 
Carbon - 42*7 - - - 42-6 
Water - 57*3 - - - 57-4 
A known weight of each was then exposed for twenty-four 
hours to a temperature of 212 0 , and afterwards for six hours 
longer ( by means of an oil bath ) to a temperature between 
