LEGUMINOS^ PRODUCIN(; TANNING MATTERS AND DYES 339 



Pterocarpus santalinus (Tree). — A fine, large tree growing in 

 Ceylon, India, the West Coast of Africa, Japan, &c. 



The wood is hard, and the colour of the exterior is dark red, with a 

 lighter shade inside. 



The red colouring principle is santal'nij the wood is used either as 

 a powder or in chips, and serves for dyeing stuffs. 



Pterocarpus angolensis (Tree). — Common in Senegal, the Gaboon 

 coast, &c. Is the source of the red sandal-wood of .Africa. It is said 

 to be richer in colouring matter than the foregoing, but its colora- 

 tions are less stable. It occurs in commerce m the form of a coarse 

 powder. The bark is used in tanning. 



Pterocarpus Marsupium (Tree). — The thick substance which exudes 

 from this tree is exceedingly astringent and is largely used in 

 medicine. The bark is used for tanning and is very rich in kinotannic 

 acid. The extracts obtained from this tree have been recommended 

 for tanning on a large scale. 



Sophora japonica (Tree). — In China the flowers are dried and form 

 the Wai-fa or Wai-Jiwa used as a yellow dye. 



C/ESALPINIE>E. 



Bauhinia purpurea (Tree).— This tree yields a bark which is used 

 both in tanning and dyeing. 



Bauhinia racemosa (Liane).— The bark is used for dyeing. 



Bauhinia variegata (Tree).— The bark is used for tanning and 

 dyeing. 



Cassia auriculata (Tree).— The bark of this tree, known as tarwar 

 in the Central Provinces, and as tangedu in the South of India, is one 

 of the best native tans known. 



The following are analyses of both young and ripe barks from 

 Mysore : — 



Young Ripe 



Tannin ... ... ... ... Ji'gz ... 20'i2 



Extract ... ... ... ... 22'35 ... 29-00 



Ash... ... ... ... ... 4'i5 ..- 6'40 



Moisture ... ... ... ... 7-26 ... 7'8o 



A sample of this bark examined at Dehra Dun contained 15*5 per 

 cent, of tannin, with a high proportion of soluble non-tannins. The 

 colour of the infusion was very light. 



Cassia fistula (Tree).— In Bengal, Southern India, and the North- 

 west Provinces, the bark of this tree is used m tanning. The propor- 

 tion of tannin is from 9-5 to i2-q per cent., but it is usually associated 

 to a large extent with non-tanning substances. 



Cassia chamaecrista (Tree).— In Guadeloupe the bark of this tree 



is used in dyeing. 



Cassia marginata (Tree).— The bark contains 6-i per cent, of 



tannin and is used in Mvsore (India). 



