Part I.] Pearson: Aiitisei>tic treatment of Sleefers. 
17 
(6) Results of sleepers treated under pressure with a mixture 
OF Green Oil and Assam Earth Oil. 
(For details of durability see Appendix V and for details of treatment and cost see Indian 
Forest Records, Vol. VI, Part IV, pp. 82 to 89.) 
jThe original series of durability tests are complete with the above 
recorded experiments, and it was not until 1915 that the writer 
commenced another series of experiments in Assam. These experiments 
are virtually a continuation of group 5, with this dift’erence that most 
of the sleepers were treated under pressure instead of in Open Tanks. 
Seven species were selected for treatment of which the greater portion 
were either ‘ Sida ’ {Lagerstroimia parviflora), ‘ Hollock ’ {Terminalia 
myriocarpa), ‘ Hollong ’ {Dipterocarpus pilosus) or ‘ Jutili ’ {Altingia 
excelsa) : of the other three species only a few sleepers were treated. 
The majority of these sleepers were laid down towards the end of 
1915 and the beginning of 1916 and so had been from 5 to 5| years 
in the line at the date of last inspection. 
(i) ‘ Sida ’ sleepers treated under pressure ivitli Solignum and Assam 
Earth Oil. 
Lagerstroimia parviflora or ‘ Sida ’ Metre Gauge sleepers, numbering 
151, were laid in the line near Moriani on the Assam-Bengal Railway over 
five years ago, after being treated with equal parts of Earth Oil and 
Solignum. The exact quantity of the solution introduced is not known, 
as they were treated after the initial absorption tests had been carried 
out. It is known, however, that they were treated on the same lines 
as the ‘ Hollong ’ and ‘ Hollock ’ sleepers, about which reference will 
be made hereafter. They are not doing very well as the sleejiers have 
a distinct tendency to crack, which is a common feature of this species 
of timber. On the other hand there are no signs of rot or white ant 
attack, which goes to prove the efficiency of the treatment. 
(ii) ‘ Hollock ’ sleepers treated with Earth Oil and Solignum. 
The ‘ Hollock ’ {Terminalia myriocarpa) sleepers were treated under 
pressure at Digboi, and absorbed from 5'3 lbs. to 8-6 lbs. per Metre Gauge 
sleeper, according to treatment. They were laid in the line over 6 
years ago and are doing very well, as 93 per cent, of them are still in 
‘ A ’ and ‘ B ’ classes, of which only 8 per cent, are in the latter This 
timber is hard, close and clean grained and is in consequence some\Yhat 
difficult to treat, on the other hand it will probably be found to give an 
extremely useful sleeper after treatment. 
[ 17 ] 
