6 
Indian Forest Records. 
[Vol. Ill 
Turning to the Open Tank or Brush methods the difficulties as to 
plants are naturally small. All that is required is an iron or zinc 
tank either placed over an open hearth or fitted inside with steam pipes 
to heat the solution. As the locality of extraction or the place of 
supply changes, the whole plant can be cheaply and easily moved or an 
entirely new plant erected at a minimum outlay of capital, and it is for 
this reason,—the question as to the value of the actual antiseptic or 
process being eliminated for the time—that the Open Tank process 
commends itself so strongly for use in India. 
Another essential difference between the Pneumatic or Hydrostatic 
and Open Tank methods is that in the former processes the timber 
affected throughout; in other words, the solution or vulcanization pene¬ 
trates to the centre of the timber, whereas in the Open Tank in the 
treatment of hard-woods the solution only penetrates a short distance 
below the surface and so only forms a shell of protected tissue round the 
log, the depth of which will depend on the density of the fibre and the 
duration of immersion. With reference to India the relative value of 
complete or only partial treatment of the wood is as yet not fully known. 
Without doubt the processes which treat the timber throughout would 
appear to have the advantage; on the other hand, decay starts from the 
outside and if the outer layers remain properly protected for a reasonable 
period of time it would be difficult for fungi or insects to make headway 
into the centre of a log. Again, the place most liable to attack is the 
end of a log and by the Open Tank process the solution penetrates 
further in this direction than into the sides, and so gives greatest protec¬ 
tion at the point most open to attack. 
Chemicals in Use for the Preparation of Antiseptic Solution. 
Many tar-oils and acids, as also salts have been employed in the 
preparation of antiseptic solutions. The best known of these are 
Creosote, obtained by the distillation of coal tar; chloride of zinc ; 
sulphate of copper ; corrosive sublimate; bi-chloride of mercury used 
in the so-called “ Kyanizing }> process ; a saccharine and arsenic 
solution used in Powellizing ; fluorine compounds; and Dinitro-phenols. 
The various patent antiseptic solutions now found on the market such as 
Avenarius Carbolineum, Atlas , Cresoyle, Cresol-calcium, Microsol f 
Bellit, BelUtoly Jodelite, etc., are generally made up of one or other of 
the above substances. 
( 79 ) 
