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with or without bark, or in squared or sawn sizes, when placed in any position in which cobra is known to 
be active, should be discontinued in the public works of this Colony, unless it is absolutely protected 
throughout its entire face and ends by copper or some other equally satisfactory protective covering. 
We would recommend the sheathing of turpentine piles, without any exception whatever, if the 
question of expense did not stand in the way, and the only exceptions we recommend are those of piles 
on the coast and in parts of Sydney Harbour, as already stated. 
The cost of coppering piles, or rather the increase of the practice of coppering piles, will at once 
claim attention ; but we would observe that the expense of the piles themselves is not the only considera¬ 
tion. If they are eaten through, the superstructure may have to be replaced, perhaps at a cost many 
times exceeding that of the piles themselves. The matter of the life of a pile involves other considerations 
than that of the durability of a post in fencing which carries no superstructure. 
Turpentine is plentiful in most of the coast forests of New South Wales. It is essentially a pile 
timber, growing as it does in suitable sizes, straight and even in the barrel, and up to 90 and 100 feet in 
length, and it is the cheapest class of hardwood procurable in the round in the Colony. If the timber be 
coppered there will be no necessity, except in rare instances, to use coppered ironbark for piles, and the 
drain on ironbark for this particular work will be very largely reduced. We desire to encourage the use 
of turpentine for piles, but subject to all the precautions we have indicated. 
Commenting on this Report, Mr. C. W. Darley, late Engineer for Harbours 
and Rivers, New South Wales, who gave especial attention to the subject of 
turpentine timber and cobra, wrote to me— 
There is one portion which, from long experience and observation, I must remain at issue with your 
conclusions. I refer to your conclusions set forth in clause Y that the bark will afford protection to the 
piles. I had in my old office a bag full of samples of bark and wood cut from turpentine piles under water, 
showing the worm-holes passing through the bark and into the timber (sap-wood only)—indeed some 
samples rather indicated that they had a weakness for the bark-covered portions. It may be that where 
the bark is closely adherent they pass through, but when at all loose they do not. I have never yet met 
with a case when Teredo sinking in one piece of wood has passed out into an adjoining piece even though 
in close contact—for instance, I have seen dozens of defective planks removed from punts, and never 
detected a worm passing from the bad one to those adjoining or to the planks inside. In 3-inch planking 
the caulking would perhaps only go half-way as shown in rough sketch,* having 11,-inch of wood in close 
contact. 
I never saw this joint crossed. May it not be the same with the bark if still loose it forms such a joint, 
while if it is closely adherent the worm may pass as shown by the samples I had in my possession, now all 
lost I fear. I never troubled about the bark being kept on after the piles were brought on to the ground 
and passed. I looked to the bark as one of the means for identifying the timber only, and I have never 
yet seen any difference in life between those driven with or without the bark. All are equally liable to 
be damaged as far as the sap-wood goes. 
When deciding to use sheathed piles I would never think of using turpentine, as they invariably 
run much larger in the girth at the butt for (say) a 40-foot pile than ironbark, as a rule, indeed, quite 50 
per cent, larger. So when sheathing is paid for at Is. 6d. per super, foot, the extra price of the timber is 
soon covered by the saving in sheathing. 
Exudation. —If the tree be wounded, there exudes a brownish liquid resin. 
If it be desired to collect this substance in quantity, the best way is to fell the tree 
and to cut it into logs, which may be inclined. The resin will exude, forming a 
ring between the wood and the bark, and may be scraped off or drained into a suitable 
vessel. It belongs to the class of bodies known as “ oleo-resins.” It has been 
Not reproduced. 
