P.aut IV.] R. S. Pearson: Antiseptic Treatment of Timber. 69 
foot, but tbis is not the rule. A heart-wood ‘ Chir 5 sleeper will take up 
5 lbs. to 6 lbs. per cubic foot within 18 to 24 hours, while a combined 
sap and heart-wood 4 Chir ’ will take up the same quantity in 6 to 10 
hours, according to its dryness. Both Dipterocarps and Terminalia 
tomentosa will take up 3 to 4 lbs. per cubic foot in 24 hours and, if 
immersed for a longer period, take up very little extra oil. It may, 
therefore, be said that in Open Tanks, when working with sleeper 
sizes, the outside working limit is 6 lbs. per cubic foot under 
favourable conditions. 
The choice of antiseptics in these experiments was governed by their 
efficiency combined with cheapness, and though the results did not, 
in some cases, justify their selection, the general lines adopted are thought 
to have been correct. To form a correct idea as the cost of treatment it 
is necessary to compare the figures obtained, with the cost of treatment 
generally adopted in Europe and America, when using a full charge of 
coal-tar creosote which, in India, would amount to Rs. 2-4-0 per broad 
gauge sleeper. 
In comparison with this figure, all our results compare most favour¬ 
ably ; nevertheless, in some cases, the actual cost of treatment was 
excessive, as in the case of Terminalia tomentosa broad gauge sleepers, 
treated with Solignum and Liquid Fuel oil, which came to Re. 1-8-4 
and of Pines , treated with the same mixture of oils, which came to 
Re. 1-9-10 per sleeper. 
From experience gained in carrying out these experiments, it has 
been possible to form more correct ideas as to the application of the 
principles of mixing oils or oils and salts together, in order to reduce cost 
without, as far as one can see, impairing the toxic value of the solu¬ 
tions. 
The first set of experiments deal with Powellized timber, a patented 
process which cannot be altered and therefore the cost of treatment 
is dependent on the market value of the ingredients used, and though 
the cost of treatment is relatively high, in favourable localities it cannot 
be considered as prohibitive. 
The second set of experiments were carried out with Avenarius 
Carbolineum, an expensive oil, which introduced in any quantity renders 
the cost of treatment prohibitive. This oil, when used alone cannot at 
present be considered for treating sleepers in India as it is too 
expensive. 
The third group of experiments were carried out with Chloride of 
Zinc and either Green oil or Avenarius Carbolineum. Here we.have a 
relatively cheap process of treatment, when using the salt and Green 
ml, for it only costs Re. 1-1-4 to treat a broad gauge pine sleeper with 
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