134 On the Strength, Durability, and Value 
astringent substance or gum of the consistency of thick tar, 
when green; but this becomes a concrete mass as the wood 
dries: where they occur the wood is of courseweakened. They 
are sometimes the thickness of a single layer only, and run 
half round the tree, asif one layer had shrunk from the other, 
and secretions were produced to fill up the void. 3 
The leaves of this tree are never sessile, but always of the 
same character as the second series of the Blue Gum. Its 
leaves exhibit no bloom, but are always of a rich dark green, 
particularly in the early stages of its growth. 
I have failed to trace any authentic cause for the prejudice 
which exists against the use of this timber for ship-building 
purposes. In a letter from Mr. Watson, appended to these 
observations, he states its shrinking to be the cause: but it 
seems never to have been fairly tried in this respect. Its 
durability in houses, when free of sap, is very great,—the 
shingles, of which great quantities are made from it, being” 
considered good for 20 years. As a ship-building timber it 
would have the advantage of lightness over the Blue Gum, 
its specific gravity being under 1000, except sometimes when 
green ;—whereas the Blue Gum never floats when free from 
sap. ‘This is a fair criterion by which to judge between the 
Blue Gum and the other species of timber when seasoned. 
The inferior Stringy-bark is said to have been exported to 
the neighbouring Colonies as Blue Gum in the earlier years 
of the trade, by which the character of the timber generally 
has been impaired. In New South Wales it is still under- 
valued. 
There are several varieties of each of the three preceding 
species of timber more or less valuable, to notice which in 
detail would require much close observation. There are 
also many members of the Huwcalyptus family of inferior 
importance in the Colony, the timber of which may no doubt 
