case that it is impossible to say for certain whether the nila of the classic authors of India denoted the self-same plant which yields the dye of that name in modern commerce. The word nila simply means dark-blue colour, and is practically synonymous with kala (black). It is often used adjectivally, such as nilgao (the blue bull), nilopala (the blue stone or lapislazuli), nilamani (the sapppire) and nilufar (the blue water-lily). Nila carries, too, the abstarct 'darkness', and only becomes a substantive to denote the dye-yielding species at a comparatively recent date. Anil comes from the Arabic al-nil through the Portuguese, and should have written annil.
The woad of the early European authors (Isatic tinctoria) is grown today in Central Asia and has been so for ages past—a region where no species of Indigofera has been known to be grown (or possibly could be grown) as a source of indigo. The Sanskrit people may accordingly have first made acquaintance with the indigo of Indigofera in India itself, and it is just possible that their nila may have originally been the woad, which with the ancient Britons was used, like the indigo of the American Indians, to dye the skin and hair. Complex and difficult though the art of dyeing with Indigo may be, it is thus more intimately associated with the early human race than any other known dye or pigment. And in India it would appear that a far larger number of plants are regularly resorted to as sources of this dye than is the case with almost any other country in the world. In addition to Isatis met with on the north-west alpine tracts and Afghnistan, mention has, for example, to be made of the rum of Assam and Central China (Strobilanthes flaccidifolius); of the ryom (Marsdenia tinctoria), found in the north-eastern tracts, a plant closely allied to the original indigo plant of Java; of an indigo plant (Tephrosia purpurea) well known in Bombay and Rajputna
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