STRUCTURE OF WOOD, &C. 
IV. 
Inquiries relative to the Structure of Wood , the specific Gravity 
of its solid Parts , and the Quantity of Liquids and elastic 
Fluids contained in it under various Circumstances j the 
Quantity of Charcoal to he obtained from it 5 and the Quan- 
tity of heat produced by its Combustion. By CouJjt Rum- 
ford, F. R. S. Foreign Associate of the Imperial Institute 
of France , 
{Concluded from p. 33 5, vol. xxxivl) 
Section V. 
Of the Quantities of Water attracted from the Atmosphere by 
Woods of various Species, after being perfectly dried. 
IT has been long known that charcoal imbibes the humidity of 
the atmosphere with considerable eagerness 3 but I have dis- 
covered that dry-wood attracts it with still greater avidity. The 
following are the details and results of a series of experiments, 
Tirade last winter, with a view to elucidate this subject. 
Having procured thin shavings, about five inches long, and 
half an inch broad, of nine different species of the woods of our 
climate ; in order more certainly to reduce them to an equal 
degree of dryness, I began my experiment by boiling them for 
two hours in water, that they might be thoroughly impregnated 
with that element. 
I then dried them well in a stove, in which they were kept 
during 24 hours, exposed to a temperature higher than that of 
boiling water, at about 50° of Fahrenheit’s scale. 
On taking them out of the stove, they were carefully 
weighed, being still hot 3 they were then suffered to remain in 
the open air for 24 hours, in a large room, whose temperature 
was uniformly during the day and night'at about 45 to 46°, F. 
This was on the 1 st of February, 1812. 
The weight of the shavings, on being removed from the 
stove, thoroughly dried, and after having been exposed to the 
air of the large room was as follows : 
