Part IL] Pearson: Antiseptic Treatment of Timber. 19 
Swarthmore College, United States, based on his analysis of Creosoted 
timbers which had lasted for many years in exposed positions, also point 
to this conclusion. 
Cases have occurred in India where imported Creosoted pine sleepers 
have failed within a relatively short period after being laid down, and 
this was probably due to faulty treatment, namely, that either the timber 
at the time of treatment was not properly dry, or that the Creosote was 
defective. 
The amount of Creosote required to preserve the timber is governed 
by two factors, (i) the structure of the wood, (ii) the purpose for which 
the timber is being treated. In the first case woods of dense structure 
are incapable of absorbing the solution to the same extent as open 
textured soft-woods. Thus beech >nd pine woods are generally made 
to take up 10 lbs. per cubic foot, while harder wood, such as oak, takes 
up 3 lbs. per cubic foot. Again the purpose for which the timber 
is intended will govern the quantity necessary for its preservation. 
As an example it may be stated that for railway ties made of coniferous 
wood 10 lbs. per cubic foot is sufficient, while for jelly or pier-piles 
exposed to the action of marine borers, as much as 20 lbs. per cubic foot 
may be necessary. Hauptmann Malenkovic gives the proportion for 
averagely hard timbers as 100 litres per metre, or taking the specific 
gravity of Creosote at 1*05, 6*56 lbs. per cubic foot. 
Cost of Method. 
The cost of Creosoting timber must necessarily vary with the cost of 
Creosote at any given place and the amount of the solution absorbed by 
different species of timber. Dr. Warth states that from experiments 
made in 1854 with the plant set up at Bally near Howrah, Sal timber 
took up only 1 lb. per cubic foot, while Sissoo took up 3| lbs. per cubic 
foot. These are fairly hard woods, so that we may take an average wood 
as absorbing 6 lbs. per cubic foot and conifers and other soft woods at 
least 10 lbs. per cubic foot. Taking a broad gauge sleeper as contain¬ 
ing 3*3 cubic feet, and the cost of Creosote as 7 annas per gallon, and its 
specific gravity 1*05 and the cost of labour for loading and unloading, 
etc., at 5 pies per sleeper, and firing, oil and other engine expenses 
( 9 * ) 
