in Extra-Tropical Countries. & 



Acacia dealbata, Link. 



Sou th-Eas tern Australia and Tasmania. This tree is generally 

 known amongst Australian colonists as Silver- Wattle. It prefers for 

 its habitation humid river-banks, and sometimes attains there a height 

 of 150 feet, supplying a clear and tough timber used by coopers and 

 other artisans, but principally serving as select fuel of great heating 

 power. The bark of this variety is much thinner and greatly inferior 

 in quality to that of the Black Wattle, yielding only about half the 

 quantity of tannin-principle. It is chiefly employed for lighter leather. 

 This tree is distinguished from the Black Wattle by the silvery or 

 rather ashy hue of its young foliage: it flowers early in spring, ripen- 

 ing its seeds in about 5 months, while the Black Wattle occurs chiefly 

 on drier ridges, blossoms late in spring or at the beginning of summer, 

 and its seeds do not mature in less than about 14 months. 



Acacia decurrens, Willdenow.* 



The Black Wattle. ' From the eastern part of South -Australia, 

 through Victoria and New South Wales, to the southern part of Queens- 

 land, also in Tasmania. A small or middle-sized tree. Its wood is 

 used for staves, for turners' work, occasionally also for axe- and pick- 

 handles and many other purposes; it supplies an excellent firewood; 

 a chief use of the tree would be also, to afford the first shelter in 

 treeless localities for raising forests. Its bark, rich in tannin, and 

 its gum, not dissimilar to gum arabic, render this tree highly im- 

 portant. The English price of the bark ranges generally from 8 to 

 11. In Melbourne it averages about 5 to 8 per ton. It varies, 

 so far as experiments made in my laboratory have shown, in its con- 

 tents of tannic principle from 30 to 40 per cent, in bark completely 

 dried. In the mercantile bark the percentage is somewhat less, ac- 

 cording to the state of its dryness it retaining about 10 per cent, 

 moisture. 1J Ibs. of Black Wattle-bark give 1 Ib. of leather, whereas 

 5 Ibs. of English Oak-bark are requisite for the same results, but the 

 tannic principle of both is not absolutely identical. Melbourne tan- 

 ners consider a ton of Black Wattle-bark sufficient to tan 25 to 30 

 hides; it is best adapted for sole-leather and other so-called heavy 

 goods. The leather is fully as durable as that tanned with oak -bark, 

 and nearly as good in color. Bark carefully stored for a season im- 

 proves in tanning power considerably. From experiments made 

 under the author's direction it appears, that no appreciable difference 

 exists in the percentage of tannin in Wattle-bark, whether obtained 

 in the dry or in the wet season. The tannin of this Acacia yields a 

 gray precipitate with ferric, and a violet color with ferrous salts; it 

 is completely precipitated from a strong aqueous solution by means 

 of concentrated sulphuric acid. The bark improves by age and 

 desiccation, and yields about 40 per cent, of catechu, rather more than 

 half of which is tannic acid. Bichromate of potash added in a 

 minute quantity to the boiling solution of mimosa-tannin produces 

 a ruby -red liquid, fit for dye-purposes; and this solution gives with 

 the salts of sub-oxide of iron black pigments, and with the salts of the 



