Part IV.] R. S. Pearson: Antiseptic Treatment of Timber. 73 
TABLE XXV— contd. 
Serial 
No. of 
experi¬ 
ment. 
No. of broad 
gauge sleep¬ 
ers on 
which the 
average is 
based. 
Total 
period of 
immersion 
in hours. 
1 
Temperature of the oil. 
Average 
amount 
of oil 
absorbed 
per sleep¬ 
er, in 
lbs. 
Remarks. 
(ii) Sap and heart-wood Pinus longifolia broad gaugi sleepzrs. 
1 
10 
17 
Heated to 80°C., dropping 
to 45°C. 
17-8 . 
* I 
Seasoned sleepers, con¬ 
taining a large propor¬ 
tion of sap-wood. 
Treated by Forest 
Economist atf Kath- 
godam in April 1914. 
2 
20 
9 
Heated to 86°C., dropping 
to 74°C. 
7-i 
Ditto 
3 
20 
6 
Heated to 50°C. 
7-5 
Ditto 
4 
20 
5 
Heated to 90° C. for four 
hours and allowed to 
cool to 82° C. 
14-5 ; 
Very thoroughly seasoned 
sleepers containing at 
least |rd sap-wood. 
Treated by Forest 
Economist at Tanak- 
pur in January 1915. 
5 
20 
5 
Heated to 71°C., dropping ; 
to 54°C. 
17-1 
Ditto 
6 
16 
8 
! Heated to 80°C., dropping 
to 65°C. 
4-25 
Sap-wood sleepers, only 
j having been out of the 
; floating stream 10 days 
and therefore contain¬ 
ing an excess of mois¬ 
ture. Treated by 
Forest Economist at 
Tanakpur in January 
1915. 
7 
20 
8 
Heated to 73°C., dropping 
to 63°C. 
♦ 
19-1 
Very thoroughly seasoned 
sleepers, 18 months out 
of floating stream. 
! The sleepers contained 
on an average one-third 
of sap. Treated by 
Forest Economist in 
November 1915. 
Total . 
126 
58 
87-35 
Average . 
1 
8-3 
i 
Heated to 76°C., dropping 
to 64° C. 
12*5 
Note.—O mitting No. 6 which contained green sleepers, the average works out to 13-85 lh\ per 
sleeper. 
From the above experiments it was ascertained that— 
( i) the maximum period of immersion necessary for heart-wood 
Pinus longifolia broad gauge sleepers, in order to make 
them take 15 lbs. of oil each, is 24 hours, with the tem¬ 
perature of the oil raised to 80°C., maintained at that 
temperature for 4 hours and then allowed to cool down. 
(ii) The maximum period of immersion necessary for sleepers 
containing ^-rd of sap-wood or more, in order to make 
them take up 15 lbs. of oil each, is 12 hours, with tempera¬ 
tures as above. 
(Hi) When dealing with sleepers which have been 18 months or 
more out of the floating stream, 18 hours’ immersion for 
[ 203 ] 
