124 
TIMBER 
or is more pleasant to use than greenheart, but it has 
one disadvantage, that of being more brittle than split 
cane." 
The greenheart which comes from British Guiana is 
more appreciated than that which grows in Dutch Guiana, 
even on the Continent, where a large quantity of the latter 
is imported. 
The weight is generally given as from 60 to 70 lbs. per 
cubic foot. Two good samples, the cross sections of large 
logs, weighed by the author, gave about 71 lbs. 
Greenheart withstands the attack of the teredo better 
than most wood ; many engineers consider that it is only 
the sapwood which is attacked and that the worm only 
goes a couple of inches into the log. Even in Bombay 
waters, where the teredo is particularly voracious, green- 
heart dock gates stood without serious damage for nearly 
ten years and then only required slight repair ; pine 
timber would be destroyed there in a few months, and 
teak in a few years. The attack of the sea worm on green- 
heart, that of the limnoria especially, is very slow in 
Great Britain ; unprotected greenheart piles stand per- 
fectly sound after being in a situation for over twenty 
years, where unprotected pine timber would have been 
destroyed in half the time. The most decisive evidence 
that greenheart piles are not proof against the teredo has 
come to the writer's notice lately. A large pier in the 
Mediterranean, with the construction of which he was 
associated, was built of this timber twenty years ago, and 
is now so seriously damaged by the worm that it is being 
replaced with ferro-concrete. This is in a locality where 
the teredo is particularly destructive. The greenheart 
decking which was on this pier is in such good condition 
after twenty years' exposure that it is intended to replace it 
on top of the new concrete piles. Greenheart is a timber 
