106 
Indian Forest Records. 
[Vol. VI 
the methods employed in carrying out these experiments are given 
below :— 
Experiment I.—Steam and Vacuum seasoning. 
This experiment was carried out with the object of determining 
whether absolutely green sleepers of Hollong (Dipterocarpus pilosus), 
could be seasoned by hot steam, as described m ^Vbiss 5 s work on timber 
treatment. 
The experiment was carried out in the plant referred to previously. 
The procedure followed was to charge the cylinder with four absolutely 
green “ Hollong ” sleepers, which were weighed before being treated. 
The sleepers were subjected to live damp steam for 2 hours, the tem¬ 
perature being gradually raised by the heating coil to 230°F., the pressure 
at that time being 10 lbs. After this the steam was cut and a vacuum 
corresponding to a column of 20 inches of mercury was applied for J hour, 
the temperature being lowered to 190°F. During this process a certain 
amount of sap was extracted, out as the sleepers, had only lost an average 
of 3*25 lbs. each, it was decided to continue the process on more drastic 
lines. They were therefore again put into the cylinder, and subjected 
to a further bath of live steam for 4 hours, at 20 lbs. pressure, and a 
temperature of 250°F. After this a vacuum of 20 inches was applied 
for | hour, the temperature being 187°F. The results are summarized 
below 
TABLE XXXV. 
Sleeper 
No. 
Weight 
before 
treat¬ 
ment, 
in lbs. 
Weight 
after 
treat¬ 
ment, 
in lbs. 
Loss of 
weight, 
in lbs. 
Total 
duration 
of 
steam¬ 
ing. 
Maximum 
tempera¬ 
ture. 
(Maximum 
pressure. 
Total 
duration 
of 
va cuum. 
Maximum 
vacuum. 
Maximum 
tempera¬ 
ture, 
during 
vacuum. 
V 
90 
81-0 
9-0 
VI 
107-5 
95-5 
12-0 
N 
VII 
90 
81-5 
8-5 
>• 
6 
250°F. 
20 lbs. 
1| hours. 
20" 
187°F. 
hours. 
VIII 
94 
84 
10-0 
1 
J 
Average 
95-4 
85-5 
9-9 
: 
1 
The sleepers treated were of metre-gauge size and therefore contained 
1'5 cubic feet of timber, a cubic foot of which weighed 63-6 lbs. green 
and 57 lbs. after steam-seasoning. Gamble gives the weight of air- 
dried 4 Hollong 5 as 43 lbs. per cubic foot; steam-seasoning, therefore, 
r 236 ] 
