Part IV.] R. S. Pearson: Antiseptic Treatment of Timber. 89' 
(ii) Treatment oe Indian species of timber by the “ Ruping ” 
process in England. 
In order to give Indian timbers treated by the Raping process a 
fair trial, a consignment of sleepers were sent for treatment to Messrs.. 
Richard Wade, Sons & Co. of Hull, who hold the right to use the patent in 
England. The first batch received by the firm were treated in the 
presence of the writer, while the remainder were treated at a later date,. 
The sleepers after treatment were returned to India to be laid in the- 
open line and kept under observation. 
The treatment consisted of raising the air pressure to 60 lbs. per 
square inch, after loading the sleepers in the cylinder, the creosote oil 
was then admitted from an overhead storage tank, in which the pressure- 
was equal to that in the cylinder. On the cylinder being filled, the pres¬ 
sure was raised to 155 lbs. per square inch and maintained at that 
point for an hour. No vacuum was applied either before or after treat¬ 
ment, nor was the timber subjected to preliminary steaming. The 
process is based on the assumption that, by first introducing air in the 
timber, the intercellular spaces are filled with compressed air, the oil 
being introduced at a higher pressure is forced into the timber, driving 
the air before it and thus forming a cushion of compressed air which, 
on the pressure being released, drives out the surplus oil from the cells.. 
That this is the case there can be no doubt, as the oil may be seen exuding 
from the ends of the timber after the pressure has been dropped and the 
timber removed from the cylinder. The results obtained by treating 
various species of Indian timber, according to this process, are tabulated, 
below :— 
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