2 



SELECT PLANTS READILY ELIGIBLE 



Acacia concinna, CandoUe. 



India. Praised by Dr. Cleghorn as a valuable hedge-shrub. 

 The pod contains Saponin. So is likewise A. latronum. 

 (Willd.), a hedge-bush. 



Acacia decurrens, Willdenow. (A. molUssima, Willd.; A. 

 dealhata, Link.) 



The Black Wattle and Silver Wattle. From the eastern part 

 of South Australia, through Victoria and New South Wales, 

 to the southern part of Queensland; in open plains a small 

 or middle-sized tree, in deep forest recesses a lofty tree of 

 singularly rapid growth. Its wood can be used for staves 

 and many other purposes, but a chief use would be 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 also important. The English price 

 of the bark ranges generally from ,£8 to £11. It varies, 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 retaining about 10 per cent, moisture. 

 Any bare barren imutilised places might here be somi most 

 remuneratively with the seeds of this Wattle-Acacia, to 

 secure a regular and continuous supply of the bark, which 

 necessarily must fall off under the indiscriminate arrange- 

 ments of obtaining the bark from the natural localities of 

 growth. The return would be within very few years; IJlb. 

 of Black Wattle bark gives lib. of leather, whereas 51bs. of 

 English Oak bark are requisite for the same results, but the 

 tannic principle is not absolutely identical. The bark of the 

 variety passing usually as the Silver Wattle (Acacia deal- 

 bata, Link), is generally of less value, often even fetching 

 only half the price of that of the Black Wattle. The 

 tannin of these Acacise yields a grey precipitate with the 

 oxyde of salts of iron, and a violet colour with sub-oxydes; 

 it is completely thrown down 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-oxyde of iron black pigments, and with the salts 

 of the full oxyde of iron red-brown dyes. 



