56 
Indian Forest Records. 
[VOL. III. 
Depth of Penetration of the Solution into Indian Timbers. 
From, experiments carried out with a variety of Indian timbers it was 
found that no general rule could be laid down as to the period of 
immersion necessary and that each species or group of species would have 
to be treated on their merits. 
Experiments were carried out with twelve Indian timbers, some of 
which were hard and close grained, others moderately so and the rest of 
open soft texture. One set of woods was given two coats of the warm 
solution at intervals of a week, and the other sets were immersed in a 
warm solution for 10 minutes. 
Plate II represents, in the upper line, two pieces (12" x 4" x 4") of 
Pterocarpus macrocar pus (Burman Padauk), the left hand one has been 
immersed, while the right hand one has been given two coats of paint. 
They were cut open after treatment to ascertain the depth to which the 
solution had penetrated, the two small sections shown on each side of the 
upright specimens present the sectional end cut out of the main blocks. 
In the same way the two lower specimens (12" X 4" X 4") demonstrate 
the depth to which the oil has penetrated into “ Sal”. It will be seen 
by examining these photographs that the solution in all cases has only 
penetrated about one-sixteenth of an inch into the sides and one-eighth 
into the ends, also that the depth to which the solution has penetrated 
into specimens a and c is slightly greater on one side than the other. 
The latter fact is attributed to the wood having rested on the bottom of 
the immersion tank and thus having been less effected on the lower 
surface than on the side over which the solution could act more freely. 
From a careful examination it was found that in the case of both the 
immersed pieces the solution had penetrated slightly further into the 
timber than was the case with the painted specimens. The above 
results clearly demonstrate that in the case of hard woods the solution 
having only acted on a very thin outer layer of the timber, a longer 
period of immersion would be necessary to protect them from decay. 
As will be seen by the results of other experiments, this is not the case 
with softer woods. 
Plate ill, specimens a and b demonstrate in a similar manner the 
depth of penetration of the oil into the timber of Picea Morinda, the 
Himalayan spruce (12" X 4" X 4") when immersed and when painted 
while Sections c and cl are specimens of Boswellia serrata (12" x 4" 
X 4"). Here we have timbers decidedly softer than u Padauk or 
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