39 
Pakt II.] Peaeson: Antiseptic Treatment of Timber. 
In support of the above theory it is only necessary to watch the 
process of treating such porous woods as Bomlax malabaricnm and Odina 
Wodier, in which as the liquid is heated masses of air bubbles appear 
on its surface, showing that the air in the timber is being. expelled, 
and after completing the process to cut open the treated specimen and 
examine the amount of absorption. 
Capillary attraction without doubt helps the absorption of the liquid, 
as a proof of which it may be said that similar results are obtained to 
those described above when immersion takes place in a cold bath ; on the 
other hand, the quantity of air expelled is less than when the piece is 
treated in a hot solution, and the amount of fluid taken up proportionately 
reduced, and further the absorption is even then not wholly due to 
capillary attraction, but to the vacuum already existing in the seasoned 
timber. 
At one time it was thought that the vacuum was produced by the 
expulsion of moisture out of the timber when heated, but this is not so, 
for were that theory correct, green timber which had been previously 
soaked in water on being heated would absorb more of the preservative 
than seasoned wood, which is found not to be the case in practice. 
As a further proof of the vacuum theory, two pieces of Dipterocarpus 
tuherculatus, the Bur man “In” wood, of equal size (12 x d X 3 ) 
were treated with Avenarius Carbolineum oil. One piece was immersed 
in the solution heated to 200° F. for 15 minutes and allowed to remain 
for 45 minutes, in the bath while it cooled down, the immersion period 
being in all one hour. The other piece was treated for one hour in the 
solution heated to just below boiling point, the temperature being main¬ 
tained throughout. Thus, in the first case, the suction caused by the 
vacuum came into play while the fluid cooled down, in the latter 
though the vacuum was formed by heating the timber it was not given 
the opportunity of acting on the piece in the same way as m the first 
case. The results were interesting, in the first case the quantity of oil 
absorbed was slightly more than double that in the latter case. 
Efficiency and Value of the Phocess. 
The efficiency and value of the process must depend on (i) the antisep¬ 
tic employed, (ii) the intensity of treatment, (iii) the adaptability of the 
various Indian timbers to such a treatment, and (iv) the purpose for which 
the timber is intended and the locality in which it is placed. 
( U* ) 
