Part I.] Pearson: ’Antiseptic treatment of Sleepers. 
27 
PART IV. Conclusions arrived at after ten years of 
experiments. 
1. General. 
Ten years have elapsed since the first lot of treated sleepers were laid 
down and dealt with according to the scheme for experiments prepared 
by the Forest Research Institute, Dehra Dun, so that it is now possible 
to summarise some of the results obtained. When the experiments were 
first started Railway Engineers looked on them with good humoured 
tolerance, and some of them were perhaps somewhat cynical. To-day 
many accept the fact that to treat certain Indian timbers will give 
satisfactory results, and this, if nothing else, is a sufiicient justification 
for having spent much money, time and thought on the experiments. 
If further justification is necessary it may be stated that one railway is 
about to erect a pressure plant, while at least three others are seriously 
contemplating doing so. The writer has no doubt in his mind that within 
a few years the treatment of sleepers will be a well established industry 
in India, as it is at present in every other civilized country. 
2. Choice of method of treatment. 
From results obtained to date the choice of treatment lies between 
{i) the Full Cell process, using either Creosote only or Earth Oil and 
Creosote and (u) Powellizing, the choice between these two processes 
being a question of cost of treatment. If Creosoting is selected, it should 
be by the Full Cell process, though cost of treatment may enforce the 
use of a certain percentage of Earth Oil, which until further experiments 
have been carried out should not exceed 50 per cent., i.e., equal parts 
of Creosote and Earth Oil. In the case of Powellizing there appears no 
reason to adhere to the old method of introducing the antiseptic in 
open tanks, as by doing so in pressure cylinders will result in deeper 
penetration. 
The other two processes tried, one by which the timber was treated 
with small quantities of a high grade Creosote and the other of treating 
first with Chloride of Zinc and then covering it with small quantities 
of Creosote, are not advocated. 
Further experiments on a fairly large scale are. however, strongly 
advocated with sleepers treated {i) according to the Open Cell or Riiping 
process, and {ii) by the Card process, which involves introducing an 
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c 
