WHARF CONSTRUCTION, SYDNEY HARBOUR. XXXV,. 
(2) The season of the year at which the tree is felled 
may exercise an important influence through the 
amount of sap in the tree at the time of felling. 
(3) The soil and latitude in which the trees are grown 
undoubtedly exercise a difference, but I have not 
sufficient data to specialise beyond the fact that 
there appear to be two kinds of turpentine tree, 
one having a thick and the other a thin bark. 
(4) Turpentine piles are usually driven with the bark on, 
as the condition of the bark plays an important part 
in the preservation of the pile, those cut in summer 
retain the bark better than those cut in winter. 
Piles cut and hauled off without being allowed to lie 
for a couple of weeks on the ground suffer damage 
very easily to the bark. All turpentine piles should 
be allowed to remain on the ground long enough for 
the bark to become attached before being handled. 
In Sydney Harbour, if not in other waters equally, the 
most serious ravages of marine borers are usually confined 
to the two or three feet about low water mark, and there 
are reasons to believe that in turpentine piles the damage 
is caused to a greater extent than is geuerally supposed by 
the Limnoria and Sphaeroma. There are instances in which 
years after a turpentine pile has been eaten through at low 
water mark by the Sphaeroma, the stump on being drawn 
has been found to be comparatively sound excepting perhaps 
for a few Teredo holes. 
My opinion of the value of turpentine as a Teredo, Sphae- 
roma and Limnoria resisting timber in Sydney Harbour has 
received such confirmation that I have recently built several 
wharves of unsheathed turpentine piles, amongst which may 
be mentioned Dalgety’s White Star Wharf at Miller’s Point, 
1,200 feet long by 40 feet wide, Howard Smith’s Jetty 300 
by 90 feet, the new Railway Jetty 500 by 150 feet, Tyser’s 
