Part IY.] R. S. Pearson - : Antiseptic Treatment of Timber. 37 
again after a 10 minutes immersion period. The results are shown 
below :— 
TABLE XI. 
Pinus longifolia. 
Pinus excelsa. 
Number of 
sleepers. 
Weight before 
1 immersion, in lbs. 
Weight after 
immersion, in lbs. 
Weight before 
immersion, in lbs. 
Weight after 
immersion in 
lbs. 
6 
855f 
895f 
683 
699 
The Pinus longifolia sleepers absorbed 40 lbs., and the Pinus ex. 
sleepers 16 lbs. In order to make each species absorb approximately 
3 lbs. each, the period of immersion for Pinus longifolia was reduced 
to 5 minutes and that of Pinus excelsa increased to 15 minutes. By 
treating the two species of Pine timber in this way, 726 Pinus longifolia 
and P. excelsa sleepers absorbed 2,789 lbs. or 3-84 lbs. of oil per 
sleeper. The penetration of the oil into the timber varied according 
to whether the sleeper contained sap-wood or not, the average depth: 
into the heart-wood of Pinus longifolia being to §" at the ends and half 
that on the sides while, in the case of Pinus excelsa , it rarely exceeded 
at the ends and J" on the sides. The temperature of the oil was raised 
to 80°C. for Pinus excelsa , and to 50°C. for Pinus longifolia as. at that 
stage of the experiments, it was thought that any tempera u r 50°C. 
for the latter species would cause the timber to crack. Further experi¬ 
ments have shown that it is possible to raise the temperature to 85°C. 
or 90°C. without damaging this species of timber. 
(b) Treatment of Dipterocarpus tuberculatus and D. alatus metre- 
gauge sleepers. 
The Dipterocarp sleepers were treated in 1912 by Mr. Leete, Divisional 
Forest Officer, Pyinmana, with the help of Mr. Marsden, the Director 
of the Burma Forest School, and Mr. Hefferman, Extra-Deputy Conser¬ 
vator of Forests. The plant used consisted of 4 small tanks made of 
galvanized iron sheeting, two of which take 5 and two 6 metre-gauge' 
sleepers at a time. The tanks in which the experiments were carried out 
are embedded in masonry to within a couple of inches from the top and' 
fitted with brick fire-places and flues running beneath them. They are 
laid parallel to each other about 8 feet apart, from centre to centre. 
Along each end of the tanks are two rails, supported on posts about 3 feet 
[ 167 ] 
