THE WORK OF THE FOREST DEPARTMENT IN INDIA. 57 



the straight or full cell process, and after treatment were 

 laid in the line. The oldest sleepers have now been more 

 than five years in the line, and under half a dozen of them have 

 had to be rejected for mechanical defects, the rest being in good 

 condition, not one sleeper having so far been rejected for 

 either white ant or fungus attack. It is not possible to say how 

 long these sleepers will last, or which antiseptic will give the 

 best result, nevertheless as pine sleepers untreated last only two 

 years, while those treated are still doing well after five years, 

 there is much to be said in favour of the treatment, especially as 

 the cost of the process has been kept within working limits. 



A very large number of timbers lend themselves to treat- 

 ment, though certain timbers do so more readily than others. 

 As a rule hard dense timbers, containing only small irregular 

 pores, are difficult to treat, though hardness does not necessarily 

 prevent the timber from absorbing the antiseptic provided large 

 straight pores are present, as is the case in Terminalia tomen- 

 tosa. Again, certain soft timbers are refractory to treatment, 

 such as silver fir, spruce and Douglas fir, all of which require 

 more drastic measures to make them absorb the oil. Generally 

 speaking straight grained timbers, those containing large ducts 

 and porous timbers readily absorb an antiseptic ; under the first 

 category fall many, though not all, of the dipterocarp timbers, 

 under the second are included many of the pines, while such 

 porous timbers as Bombax malabaricum, Odina Wodier, Kydia 

 calycina, etc., when in a dry state, soak up the antiseptic faster 

 than is convenient for working purposes. 



When considering the selection of timbers which after 

 treatment might be suitable for sleepers, mechanical strength 

 has to be considered as well as durability and facility of treat- 

 ment, for unless the sleeper is sufficiently strong to withstand 

 the wear and tear to which it will be subjected, however well it 

 may be treated it will be rejected for mechanical defects at an 

 early period of its life. Again, the outturn of sleepers from 

 any locality together with the cost of extraction has a direct 

 bearing on the commercial possibility of supplying treated 

 sleepers to the railways. Based on the above considerations it 

 is thought that the species of timber most suitable for treatment 

 as railway sleepers are Dipterocarpus turbinatus and Termina- 



