Part IV.] R. S. Pearson: Antiseptic Treatment of Timber. 121 
eand air at the bottom of the post, conditions unfavourable to the action 
of fungoid growth. It necessarily follows that the greatest measure of 
protection must be given to the most vulnerable portions of the timber. 
In the case of fencing posts, which are generally not buried deep in the 
ground, it is not usually economically sound to differentiate between 
the lower and middle zones and, therefore, to facilitate matters, it is 
customary to treat the whole of the lower end of the post. In the case, 
however, of telegraph poles, which have to be buried deep in the ground, 
and especially when large numbers have to be treated and economy 
is a consideration, onl^ about 2 feet above and below ground are treated. 
These remarks apply to cases in which the poles only contain heart- 
wood ; if, on the other hand, sap-wood is present the whole of the post 
.should be treated, special attention being paid to the lower end. 
In cases of mining props destined for erection in main galleries, in 
other words when the supports are of a more or less permanent nature, 
the posts should be treated throughout their length to refusal either in 
Open Tanks or preferably under pressure. The same remarks apply 
to timber to be placed in water, in such situations for instance, as weirs 
or sluice gates, which are subjected to the alternate action of water 
and a process of drying. + 
In the event of there being sufficient timber to justify the erection 
of an Open Tank , in which to treat the posts or telegraph poles, the best 
type of tank in which to treat the butts is a circular tank of from 6 feet 
to 8 feet diameter and of sufficient height to enable the ends of the post 
to be submerged in the antiseptic to the required depth. 
Before leaving this subject, it should be mentioned that when con¬ 
sidering the treatment of the ends of posts only, it is not intended to 
convey the idea that it is not better to treat the timber throughout : 
the idea of partial impregnation is only advocated from the point of 
view of economy. Moreover, it should be clearly understood that 
treatment under pressure is preferable to Open Tank treatment and 
• that this treatment is again preferable to the Brush method of treatment, 
the selection of the process to be adopted depending on the quantity 
.and quality of the timber to be dealt with and the purpose for which 
it is destined. 
(2) General discussion. 
It must be admitted that India is far behind most other civilized 
countries in the matter of treating timber and this may be attributed 
to the large supplies of timbers exceptionally durable in their natural 
estate. These supplies are falling short of the ever-increasing demand, 
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