62 
Indian Forest Records . 
[VOL. VI 
The results of these experiments show that Dipterocarpus alatus is 
e asier to treat than D. tuberculatus, as 12 hours in the case of the 
former and 16 hours in the case of the latter, are required to make 
a metre-gauge sleeper take up about' 5 lbs. of oil. On the other hand, 
the results show variation in absorption by the same speci es, when 
treated under precisely the same conditions. This is attributed to the 
varying percentages of sap-wood and possibly moisture in each batch 
of sleepers. Another point brought out by these experiments is that 
on account of the long immersion period necessary to make the sleepers 
take up even a small quantity of oil, by the Open Tank process, it would 
probably be cheaper and certainly more expeditious, to treat them 
under pressure. 
(c) Treatment of Terminalia tomentosa broad gauge sleepers , with 
Solignum and Liquid Fuel oil. 
The Terminalia tomentosa broad gauge sleepers were treated in a 
mixture consisting of 33 per cent, of Solignum and 67 per cent, of Liquid 
Fuel oil, the object aimed at being to introduce 9 to 10 lbs. of the solution 
into each broad gauge sleeper. The work was started by the writer 
who, after fixing the immersion period necessary to make the sleepers 
take up the required quantity of oil, entrusted the work to his assistant, 
Babu Gy an Singh. 
The sleepers were prepared from trees felled during the working 
season of 1913, in the Betul forests, and were treated in November 1914, 
having therefore had 16 to 18 months in which to season. An attempt 
was made to treat these sleepers in February 1914, but as they were 
at that time insufficiently seasoned, the work was postponed until the 
following November. 
To ascertain the period of immersion necessary in order to make the 
sleepers take ‘up 9 to 10 lbs. of oil, 25 per cent, of the sleepers were 
weighed before and after treatment, with the following results :— 
TABLE XXIII. 
Species. 
Average 
absorption, 
per sleeper, 
of 19. 
Temperature of the 
solution. 
period of immersion. 
Terminalia tomentosa, broad 
lbs. 
10-1 
89°C. 
dropping to 49°C. 
3 hours heating and 21 
gauge sleepers. 
hours cooling=24 
hours. 
9-4 
90°C. 
„ 51°C. 
Ditto 
8-95 
90°C. 
„ 50°C. 
Ditto 
10-3 
90°C. 
„ 53°C. 
Ditto 
9-25 
90°C. 
„ 51°C. 
Ditto 
1 
10-6 
90°C. 
„ 45° C. 
Ditto 
Average absorption per broad gauge sleeper of 114 sleepers^=9-77 lbs. 
[ 192 ] 
