A METHOD OF IDENTIFICATION OF SOME HARDWOODS. 24] 
A METHOD OF IDENTIFICATION OF SOME 
HARDWOODS. 
By M. B. WELCH, B.Sc., A.I.C., 
Economic Botanist, Technological Museum. 
[Read before the Royal Society of N. S. Wales, December 6, 1422. | 
THE HKucalyptus timbers which are by far the most import- 
ant group of the Australian hardwoods, are, in many cases, 
extremely difficult to determine with accuracy. Although 
there is little in common between the open grained Moun- 
tain Ash type such-as Hucalyptus Delegatensis, and the 
close grained “‘ Boxes,” e.g. H. hemiphloia, yet certain of 
these timbers fall into groups, which possessing similar 
texture, colour and weight, are very difficult to separate. 
Again, though a timber such as Blackbutt, H. pilularis, is 
usually distinct from Spotted Gum, EH. maculata, at times © 
these timbers resemble each other to such an extent that 
it is impossible to classify them with certainty, witbout 
information as to the nature of the bark or other morpho- 
logical characters. Similarly the Sydney Blue Gum, E. 
saligna is very difficult to separate, at times, from the 
Mahogany, H. resinifera, or Jarrah, E. marginata. Colour 
of the timber is liable to vary within limits, even in the one 
log, and this variation is sufficient to make any very exact 
colour classification impossible. The specific gravity of 
any one timber is by no means a constant, and may vary 
ten pounds per cubic foot or even more in the one species, 
being dependent on the conditions of growth. Although 
some woods are much lighter than others, yet, when the 
difference in average weight is not marked, this variation 
renders too critical a comparison, based on weight, of little 
P—December 6, 1922. ; : entaat 
