TEREDO-RESISTING- RITER WORKS. 
757 
of this kind of eucalyptus for harbour works, when many woodcutters 
so persistently endeavoured to induce the Trust to accept piles thereof, 
and so vehemently challenged the accuracy of my opinion relative 
thereto.” 
The following is from a South Australian parliamentary report: — 
“ Jarrah makes excellent piles in both salt and fresh water. Some 
karri piles have stood well in bridge work, but karri ( Eucalyptus 
diversicolor ) is unsuitable for piles in sea water, being much more 
subject than jarrah to the attack of the Teredo 
I find from the same report that in Western Australia experi- 
ments have been tried with karri and jarrah by submerging the 
timbers in the sea at Fremantle for one year. The result is stated 
as follows : — “ The karri being completely riddled by the Teredo 
naval is , while the jarrah is perfectly sound.” 
With respect to the apparent immunity of the Western Australian 
jarrah ( Eucalyptus marjinata) from the attack of the Teredo , it is to 
be noted that this particular test only extended to one year’s exposure 
in the sea ; but as I have found some other timbers able to resist 
the Teredo for that length of time which were afterwards destroyed, 
I think the one year’s test of any timber not decisive. Nor do I 
consider a small number of pieces of any particular timber a sufficient 
test, as I have found, in a large work consisting of over 200 piles 
of the same timber, about three piles out of that number had 
resisted the Teredo without any sheathing, whilst all the rest were 
destroyed. 
I find also that some authorities claim that Western Australian 
jarrah timber is able to resist the Teredo , whilst the Yictoriau and 
South Australian authorities already quoted state it is successfully 
attacked by the Teredo. On account of this difference of opinion I 
think the whole question of the qualities of various Australasian 
timbers for resisting the Teredo and other destroyers would be a 
proper one for further and united investigation, and perhaps a 
research committee of this Association might undertake the investiga- 
tion and report on the matter. 
TEREDO-RESISTING RIVER WORKS. 
I have been endeavouring during the last few years to discover 
some means of effectually preventing the destructive action of the 
Teredo on the extensive timber works on the river Fitzroy belonging 
to the Municipal Council of Rockhampton, and have now succeeded 
in effecting that object by means of a composite construction of 
hardwood timber and Portland cement concrete which I adopted in a 
wharf recently erected. 
In this case I have had timber piles driven into the river bed at 
intervals ol 5 feet along the front of the intended wharf, and also on 
the line of the two ends of the wharf returned from the river front 
to the shore, and built walls of cement concrete enclosing these piles 
in the centres of the walls. Behind this front row of piles are three 
other rows, the piles here being at greater intervals in the rows, all 
driven down into the rock. Timber waling-pieces are bolted to the 
tops of the piles, reaching from the river front to the piles on the 
3 A 
