68 
It is also evident that the total or partial removal of the sap from 
wood will retard its decay. But even if all sap were removed decay 
would naturally set in, if the entrance into the cells of air and water 
containing spores is permitted, or if no means are adopted to prevent 
their growth when introduced. 
To prevent air and water from entering the wood its cells may be 
filled with some substance not liable to decay. To prevent organic life 
from springing up in the wood cells, antiseptics are introduced into them 
in the form of solutions, which act as poisons on all kinds of spores and 
bacteria. 
Note. — There is no doubt whatever that wood can be preserved, successfully and 
to commercial advantage, to a much greater extent than is generally believed. 
To experts in tbis field little need be said ; they are aware of its extent, what has 
been accomplished, and the possible advantages. They know that the preservation 
of wood has been carried on in England and in several countries of Europe for a 
great many years on a very extensive scale and with the most satisfactory results, 
several processes being in use whose efficiency has been thoroughly established. Ex- 
perience in this country has not been satisfactory, owing to a want of appreciation 
of certain conditions, very different from those found abroad. Among these it is 
noticeable that we have usually green timber to treat instead of seasoned wood, and 
that in some localities timber is yet too plentiful, and consequently cheap, to admit 
a preserving process being employed to commercial advantage. In some cases again 
experiments have not been satisfactory, owing to the great distances to which wood 
had to be transported for treatment and then to be sent back. — H. C. 
METHODS OF TREATMENT. 
The methods which are used, either simply or in combination with 
each other, in the preservation of wood, are, — 
(1) Steeping in water or in antiseptic solutions. 
(2) Forcing a current of water or of antiseptic solution longitudi- 
nally through the ducts of the wood, either by pressure or by suction — 
the Boucherie process. 
(3) Steaming in closed vessels. 
(4) Bemoviog air and vapors from the cells by creating a vacuum 
around the wood in a closed vessel, and then injecting the antiseptic 
solution into the wood by applying pressure to the solution. 
(1) Steeping. — When wood is steeped in running water its sap is 
diluted and gradually displaced. This is the cause of the greater dura- 
bility of rafted lumber as compared with that which has not been sub- 
merged in water. 
But the process is necessarily slow, and if the water in which the 
wood is submerged contains sediment, the process is impeded. 
Steeping is also used for impregnating wood with antiseptic solutions. 
To allow such solutions to enter the wood the latter should first be 
freed from water, either by air-drying or by exposing it to heated air 
in kilns. Steeping requires much time (from one to two or three weeks) 
andean never effect a thorough impregnation of the wood. The structure 
