4 
On the Preservation of Timber. 
The nature of this decay, or eremacamis, of timber depends, of 
course, on the conditions under which it takes place, and which 
vary accordingly, whether air and moisture are present or absent, 
and, thirdly, when the wood is covered with water. It is materially 
promoted and accelerated by the fermentation induced bv air and 
moisture at an elevated temperature, among the saccharine and 
allied bodies, which are converted into acetic acid, carbonic 
acid, &c. This leads to the putrefaction of the azotised matter, 
while the wood becomes covered with cryptogamic plants, and 
is at length changed into a brown or black substance called mould 
or humus. Hence, wood of a more recent formation undergoes the 
conversion most rapidly, because its canals, being less incrusted 
with the ligneous compounds, contain more sap, and consequently 
more albuminous or azotised matter. 
Chemical Character of Decay. — An analysis of this 
humus at once explains the chemical nature of the change 
which the wood has undergone, which may be represented by 
the following formula : — 
c. H. o. c. H. 0. 
Composition of oak wood 3(5 22 22 
Oxygen absorbed from the air .. .. 4 
36 22 26 
Products. 
Humus left behind 34 18 18 
Four atoms of water 4 4 
Two ditto carbonic acid 2 0 4 
36 22 26 
It is, therefore, a process of slow but true combustion, by 
which the proportion of carbon contiiiually increases in tlie 
residual product up to that point Avhen the affinity of the carbon 
for the remaining hydrogen balances that of the oxygen. 
Insect Food. — Further, it is the albuminous azotised matter 
in the sap which serves as nourishment to the various insects 
which occasion such destruction in timber. 
Objects to be accomplished. — The principal cause of the 
eremacausis and destruction of timber being due to tlie presence 
of azotised matters existing in a soluble state in the sap, it is 
clear either that these soluble matters ought to be removed, 
or that the proper agents to employ for the preservation of 
the wood ouffht to be those which secure the soluble matter 
from decay by forming insoluble compounds with them, and 
rendering them unfit for the food of animals. 
As the first method is impracticable, the problem resolves itself 
into the employment of suitable antiseptic materials, and the use 
of such mechanical means as will enable the material to pene- 
trate into the interior of the cells, fibres, and vessels, as well as 
the interstices which separate them. 
