10 Select Plants for Industrial Culture and 



1 ton of bark yielding 4 cwt. of extract of tar-consistence [Sim- 

 monds], thus saying much freight and cartage. Messrs. Borrow 

 and Haycroft, in South Australia, are now producing a thick fluid 

 extract from Wattle-bark and twigs by steam machinery, the average 

 percentage of mimosa-tannic acid in this extract being 38-20. 

 Catechu can be realized from the thick tan-liquid by mere exsicca- 

 tion. 



Tan-extract is best obtained from the bark by hydraulic pressure 

 and evaporation of the strong liquid thus obtained in wide pans under 

 steam-heat, or better still, to avoid any decomposition of the tannic 

 acid, by evaporation under a strong current of cold air. For cutch 

 or terra japonica the infusion is carefully evaporated by gentle heat. 

 The estimation of tannic acid in Acacia-barks is effected most ex- 

 peditiously by filtering the aqueous decoction of the bark after 

 cooling, evaporating the solution and then re-dissolving the residue in 

 alcohol and determing the weight of the tannic principle obtained by 

 evaporating the filtered alcohol-solution to perfect dryness. 



The cultivation of the Tan- Wattle is extremely easy, being 

 effected by sowing either broadcast or in rows. In Australia 

 particularly it is capable of immense extension, often on otherwise 

 unutilised ground, and within the grasp of the crudest of labour. 

 Tanners in colder countries might acquire in the nearest warmer 

 regions poor inexpensive land, to provide an independent supply of 

 this valuable bark from comparatively near shipping places. Seeds 

 can be obtained in Melbourne at about 5s. per lb., which contains 

 from 30,000 to 50,000 grains ; they are known to retain their 

 vitality for several years. For discrimination in mercantile trans- 

 actions it may be noted, that the seeds of A. mollissima are some- 

 what smaller, comparatively shorter, rounder and not so flat as 

 those of A. dealbata, while the funicular appendage does not extend 

 so far along the seeds, nor is the pod quite so broad ; from those of 

 A. pycnantha they differ in being shorter, thus more ovate than 

 elliptical. See in reference to this and kindred subjects also J. H. 

 Maiden's " The useful native plants of Australia." 



Seeds should be soaked in warm water before sowing. Any bare, 

 sterile, unutilised place might most remuneratively be sown with 

 this Wattle- Acacia ; the return could be expected in from five to 

 ten years. Full-grown trees, which supply also the best quality, 

 yield as much as 1 cwt. of bark. The rate of growth of the tree 

 is about 1 inch in diameter of stem annually. It is content with the 

 poorest and driest soil, although in more fertile ground it shows 

 greater celerity of growth. Bark from trees, grown on very cal- 

 careous soil, is less strong in tan. This Acacia is perhaps the most 

 important of all tan-yielding trees of the warm temperate zones, 

 for its strength in tannic acid, its rapidity of growth, its contentedness 

 with almost any soil, the ease with which it can be reared and its 

 early yield of tanner's bark, and indeed also gum and stave-wood. 

 This tree is to be recommended for poor land, affected with sorrel. 

 It is hardier than Eucalyptus globulus, thus enduring the climate of 



