50 
ADDITIONS 
Acacia pycnantha, Bentham.* 
Victoria and South Australia. Though frequent in many parts 
of our colony, this tree, known as the Golden Wattle, deserves 
even here extensive cultivation, mainly for the sake of its bark, 
rich m tannin. It is of rapid growth, will succeed even in sandy 
tracts, and yields seeds copiously, which germinate with the 
greatest ease. It is never a large tree. By improved methods the 
fragrant oil of the flowers could doubtless be fixed, though its 
isolation might be difficult and unremunerative. Experiments 
m the writer’s laboratory have shown that the perfectly dried 
bark contains about 25 per cent, of mimosa-tannin The 
aqueous infusion of the bark can be reduced by boiling to a dry 
extract, which in medicinal and other respects is equal to the 
best Indian catechu, as derived from Acacia catechu and A. sundra 
It yields approximately 30 per cent., about half of which or more 
is mimosa-tannic acid. This catechu is also of great use for 
preserving against decay articles subject to exposure in water, such 
as nets, fishing lines, &c. While according to Mr. Simmons the im- 
port of the bark of oaks and hemlock-spruce into England becomes 
every year less, and while the import of sumach and gambir 
does not increase, the annual demand has, since the last 20 years 
become doubled. Probably no other tanning plants give so quick 
a return m cultivation than our Acacia pycnantha and particularly 
A. ducurrens. To the latter, the Black Wattle is already alluded 
“ th ? ***** trees ; the following additional notes 
may farther show the importance of this neglected tree. The 
ng ish price of the bark ranges generally from £8 to £11 It 
vanes, so far as experiments under my direction have shown, in 
its contents of tannin from 18 to 33 per cent. In the mercantile 
bark the percentage is somewhat less, according to the state of 
its dryness— it retaming about 10 per cent, moisture. Any bare 
barren unutilized places might here be sown most remuneratively 
with the seeds of this Wattle Acacia, to secure a regular and 
con muons supply of the bark, which necessarily must fall off 
under the indiscriminate arrangements of obtaining the bark 
from the natural localities of growth. The return would be 
within very few years. l£ lb. of Black Wattle bark gives 1 lb. of 
eather, whereas 5 lb. of English Oak bark are requisite for the 
same results, but the tannin principle of both is not absolutely 
identical The bark of the variety passing generally as the 
Silver Wattle (Acacia dealbata, Link), is generally of less value 
° te » eye m/ etCbing ° Bly LaJf the P rice of ttat of the Black 
Wattle. The tannin of these Acaci® yields a grey precipitate 
with the oxyd salts of iron, and a violet colour with sub-oxydes • 
it is completely thrown down from a strong aqueous solution by 
