TEREDO -RESISTING RIYER WORKS. 
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illustration of this loss through the work of the Teredo , I may mention 
a large timber wharf in Rockhampton — the piles of turpentine timber 
from New South Wales— built about ten years ago at a cost of over 
£7,000, and which has been almost entirely destroyed by the Teredo in 
that time. I am informed that the owners of the wharf and their 
engineer were advised at the time of its construction that the timber 
used for the piles and other submerged portions of the structure was 
proof against the Teredo , but the result has shown that this timber is, 
like most others, liable to destruction in the end. It is a curious fact, 
however, that a few piles, about three out of over 200 piles in all, 
have so far successfully resisted the animal ; but I think this is 
accounted for by the fact that the bark has not yet been ruptured, as 
has been the case with the rest of the piles. The whole of the piles 
in this work were driven with the bark on, and of course some piles 
would have the bark in a more perfect condition than others. 
PROTECTING TIMBER AGAINST THE TEREDO. 
Many expedients have been adopted to guard timber work 
against Teredo attacks, but the most of them have hitherto been only 
partially successful. One expedient is to drive nails with flat and 
square heads into the timber so closely together as to prevent any 
access by the animal. The most common method is to sheet the 
timber with copper or muntz-metal, having overlapping joints laid as 
closely as possible. These methods are, however, sometimes rendered 
useless by the metal being torn and the wood exposed ; the slightest 
opening being made, the Teredo can attack and destroy the timber as 
easily as if no sheathing had been applied. 
Various other applications have been tried, especially in Holland 
and the United States of America, where marine and river works are 
almost universally of timber construction, but with little or no success. 
In San Francisco the following preventive applications to wooden piles 
in the harbour works have been experimented upon, namely : — 
1. The piles were jacketed with large sewer-pipes, and the 
space between the pipe and the pile filled in with cement 
concrete. The result was the piles were not attacked 
except in places where the pipe had broken. 
2. The piles were coated with different kinds of compositions — 
one a mixture of asphalt urn and burlap; others with varie- 
ties of marine cement. These wore applied to different 
kinds of American timbers, and allowed an exposure under 
water of a little over five years. The result was that all 
the piles were destroyed by the Teredo naval is, which is 
prevalent in the harbour of San Francisco. 
THE TEREDO AND QUEENSLAND TIMBERS. 
Some years ago my attention was drawn to a timber of this locality 
(Central Queensland), commonly called “swamp mahogany,” the 
Tristania suaveolens of the order Myrtacese, and which was said by 
several old residents to be thoroughly proof against the Teredo. 1 had 
