190 Transactions. —Miscellaneous. 
Art. XVITI.—On a means of selecting the most durable Timber. 
By Jons Bucwanan. 
[Read before the Wellington Philosophical Society, 21st September, 1877.] 
Tue purpose of the present paper is to explain a method by which timber 
of the greatest utility, from trees of any species, may be determined. 
In the selection of timber for constructive purposes the only guide 
hitherto has been the prevailing vague opinion that the timber of certain 
trees is durable; experience, however, has often proved that failures take 
place with some of those species most highly valued, such as totara, 
( Podocarpus totara). In all such cases the failure has probably resulted from 
that indiseriminate system which prevails of cutting down every tree within 
reach, including young immature trees and quickly-grown mature trees on 
rich alluvial bottoms, which always produce an inferior timber ; the use of 
such inferior timber in wharves, piles of all kinds, or fence stuff, can only 
result in premature decay. 
As a means to enable engineers to determine the value of any timber 
I propose the adoption of a standard test of weight, based on an average 
weight determined from at least twenty measured cube specimens of each 
species, the specimens to be well seasoned, procured from different districts, 
and grown under different conditions of growth. By comparing specimens 
of the same cubic bulk of any timber with its own standard, the most durable 
of that kind may be selected; as it may be accepted as an axiom in the 
physiology of timber, that the best will possess the closest structure, contain 
the largest amount of secretions, and consequently will prove the heaviest 
and most durable. 
If, however, our New Zealand timbers in their natural state, and selected 
by the test of weight, do not come up in durability to the necessary require- 
ments, there is still in reserve the auxiliary means used in other countries, 
by which inferior timber is made durable, such as charring, or by the infusion 
of antiseptic fluids into their structure, and it is possible the colony may ere 
long waken up to the fact that the introduction of such preservatives has 
been already too long delayed. : 
