400 VEGETABLE SUBSTANCES. 



obtained, they use the roots of a desert herb called 

 oerk ; this is about three spans long, and as thick as 

 a man's finger ; the outer skin serves as a substitute 

 for the pomegranate peel, but dyes the leather red. 

 Of leather so prepared, the rawouye, or large water- 

 skins, are made ; these are sometimes soaked a 

 second, and even a third time, in the mixtures above 

 described, a month after the first dyeing. For some 

 time the rawouye imparts to the water an anstrin- 

 gent, bitter taste ; this, however, the Arabs like *." 



Many different plants are capable of affording 

 green colours, but these are of little practical use, as 

 they are all fugitive, and hitherto neither science nor 

 experiment has succeeded in discovering any artifice 

 by which they may be rendered more lasting. 

 D'Ambourney, indeed, after many trials, supposed 

 that he had extracted a durable green from the ber- 

 ries of the rhamnus frangula, or berry-bearing 

 alder, when the substance to be acted upon had been 

 previously prepared with tartar, nitric solution of 

 bismuth, and chloride of sodium. But either this 

 has never been put to the test among practical dyers, 

 or it has been found not to possess an advantage 

 which would have rendered the discovery so valu- 

 able. 



Among those plants which yield a fine, though 

 evanescent green, are the field broom-grass, or 

 bromus secalinus ; the chilca, or oestrum ; wild cher- 

 vil ; purple clover; and the common reed. 



Saffron is not properly speaking a dyeing drug, 

 being too expensive to be so applied in England ; but 

 it is an ingredient so rich in colouring matter that it 

 should not pass wholly unnoticed, especially as it is 

 occasionally employed in the dye-houses of some 

 # Buckhardt's Notes on the Bedouins and Wahabys. 



