57 
Part II.] Pearson: Antiseptic Treatment of Timber. 
“ Sal ** and the depth to which the antiseptic has penetrated is in 
proportion greater. Specimens a and c were immersed, while the 
specimens b and d were treated with the brush. Both the immersed 
specimens show greater absorption than those on which the antiseptic 
was only painted, while in all four cases a very fair portion of the outer 
tissue has been thoroughly impregnated. Were the timbers so treated 
destined to be used as fencing posts, the amount of absorption would 
be sufficient to protect them from decay, though were they intended for 
sleeper woods the period of immersion would probably have to be extend¬ 
ed until the antiseptic had had time to sink deeper into the timber. 
Plate IV, specimens a and b exhibits the penetration of Avenarius 
Carbolineum oil into the timber of Finns longifolia, the Chir of the 
Himalayas and specimens c and cl into that of Finns excelsa , the blue 
pine, both fairly soft woods. In this case it must be remembered that 
the specimens treated are exactly half the size (12" x 4" x 2") of those 
shown on Plates II and III so that the depth of penetration in this 
instance appears greater than in the case of the larger specimens ; on the 
other hand, the solution has penetrated to the centre of the immersed 
“ Chir ” specimen and also has sunk well into the Blue Pine timber. 
In both cases the immersed specimens a and c show greater absorption 
than those treated with the brush b and d. 
The above results clearly indicate that 10 minutes* immersion in a 
warm solution is insufficient for hard woods. It will probably be neces¬ 
sary to treat the conifers for 15 minutes to half an hour, the moderately 
harder species for a period varying from two hours and upwards and very 
hard timber for 12 to 24 hours according to the density of the wood and 
the size of the scantlings under treatment. 
Amount op Absorption op the Oil by Indian Timbers. 
When calculating the quantity of a solution absorbed by a B. G. 
sleeper based on data obtained by treating small pieces of timber, two 
factors must be taken into account ; (i) the volume of the treated piece, 
(ii) the superficial area over which absorption takes place. Presuming 
the solution penetrates to the centre of the timber, the calculations have 
to be based on volume ; on the other hand, if only the outer layers of the 
treated pieces are affected, the calculations must be based on the super¬ 
ficial area of the piece under treatment and not according to the volume 
( 130 ) 
