248 M. B. WELCH. 
devised, particularly the Kucalypts, some of which closely 
resemble each other in colour, weight and texture, an 
examination was made of an extract obtained by boiling a 
definite weight of shavings in a known volume of water. 
The tests carried out on the Kucalypts show that. it is 
impossible to generalise or to prepare any key to identifica- 
tion along these lines. The method must be used with 
caution on account of the variation in behaviour found in 
the same timber. It is of value in many cases, however, 
and without doubt is more accurate in these species than 
any ordinary superficial examination. It is only safe to 
use this method by actual comparison of the extract from 
the doubtful specimen, with extracts similarly prepared. 
from authentic specimens of the woods with which the 
comparison is being made. 
TI am indebted to Prof. A. A. Lawson, D.sc-, for his kindly 
criticism in this work. 

