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CHAPTER XII. 



LECUMINOSiE PRODUCING TANNING MATTERS 



AND DYES. 



Among the Leguminos^ an important part is played by 

 plants which produce tanning matters and dyes. 



It is generally the bark of these plants which is used in 

 the preparation of tan, a powder from which is derived the 

 tannin used in preparing hides, in the manufacture of ink, 

 the tanilication of wines, <S:c. 



Colouring matters are extracted from the flowers, leaves, 

 wood, or bark; in other words, taking the various species 

 generally, from every portion of the plant. 



Numerous species of acacia and cassia yield tanniferous 

 barks of excellent quality. They are easily suited as regards 

 the nature of the ground, thriving best, however, in a light 

 soil with a clay subsoil. They are usually grown in rows 

 at intervals of 12 ft. This interval may vary with the variety 

 or according to the richness of the soil, but in no case 

 should the trees be planted too closely or they will yield a 

 thinner and consequently a less valuable bark. 



In order to accelerate the germination of the seeds it is 

 advisable either to immerse them in concentrated sulphuric 

 acid, subsequently washing them in running water, or to 

 allow them to soak in water or even in boiling water. At 

 the Agronomic Station at Reduit, where a few experiments 

 have been made by M. Boname, the best results have been 

 obtained with boiling water. The water is poured over the 

 seeds and allowed to cool of its own accord for forty-eight 

 hours. In this way seeds have been made to germinate in 

 ten to twelve days. This method is only recommended, 



