leguminos;e producing tanning matters and dyes 343 



Acacia decurrens (Tree). — The proportion of tannin in the bark 

 may vary from 36* i to 41 '4 per cent. ; non-tannins 4*4 to q"i per cent. ; 

 insoluble matter 3Q'2 to 40-2 per cent. [Black 7c>attlc.) Bark largely 

 used for tanning. 



Acacia melanoxylon (Tree). — The bark gives 28'6 per cent, of 

 tannin, with limits of 20 to 32 per cent. .\ very fine tree, the wood of 

 which is used for fuel. The bark is in large demand for tanning 

 pur])oses. 



Acacia Farnesiana (Tree). — A sample of bark taken from Southern 

 India gave 2'8 per cent, of tannin, extracted by means of warm water. 

 This acacia occurs throughout the Tropics and is largely grown in 

 France for its flowers, " fleurs de cassie." It is said that at Dacca 

 the bark is mixed with salts of iron in the manufacture of a deep 

 black dye. In new Caledonia and Guiana the fruits are used for 

 dyeing purposes. 



Acacia Intsia (Tree). — The bark or fresh leaves are used in dyeing 

 as mordants. 



Acacia pennata (Tree). — The bark contains 8'8 per cent, of tannin. 

 Wi.th salts of iron it yields a black colouring matter. It is an article 

 of commerce, being exported from Concan and used in Bombay for 

 tanning fishing nets. 



Acacia Suma (Tree). — Fairly common in Bengal and Southern 

 India. In damp soils it seems to be of luxuriant growth. It yields a 

 white bark, which is used in the tanning industry both in Africa and 

 in India. 



Acacia penninervis (Tree). — The bark is rich in tannin and contains 

 37' 7 per cent, of that substance; 5"2 per cent, of non-tannins; 46' i per 

 cent, of insoluble matter. 



Acacia Adansonii (Tree), Acacia nilotica (Tree), Acacia Sing (Tree). 

 — All give i)ods used in dyeing and tanning. 



Acacia leiopiiylla (Tree). — This species is very much exploited in 

 Australia for its bark, which contains as much as 30 per cent, of tannin. 



Acacia leucophloea (Tree). — The bark of this acacia may yield a 

 tan of a quality ec|ual to that of Acacia araJy'ica. It contains 20'8 per 

 cent, of tannin (sample from Mysore). Another sample, from Dehra 

 Dun, only gave Q'33 per cent., with a high proportion of soluble non- 

 tanning substances. This plant is also used in dyeing; the leaves are 

 used for dyeing black. 



Acacia Catechu (Tree). — Acacia Catechu is the tree which yields the 

 product known as catechu or cutcli. It has been known for several 

 centuries, for European writers, such as Barbosa (1516), speak of the 

 cacJio exported from Cambay to Malacca. Garcia de Orta gave a 

 complete account of the plant and of the manufacture of the extract in 

 1574, but it was only towards the end of the 17th century that 

 A. Catechu attracted European attention. 



There are three forms of catechu : — 



(i) The black catechu, chiefly used for industrial purjDoses. 



(2) The pale Indian catechu, a crystalline substance employed in 

 medicine. 



