INDIGO. 



193 



advantageously cultivated anywhere except within the tropics, 

 a higher mean temperature than 60° being absolutely necessary 

 for its vegetation. The seed is sown in furrows a foot apart 

 from each other, and two or three inches in depth. Sufficient 

 moisture causes it to shoot above the surface in three or four 

 days, and it is usually fit for gathering at the end of two months. 

 When it begins to flower it is cut with a sickle a few inches 

 above the roots, and furnishes, after six or eight weeks, a second 

 crop. The cultivation of indigo would thus seem to be extremely 

 profitable, but the sun, which so rapidly improves and invigo- 

 rates the plant, calls forth at the same time a multitude of 



'-=. -^^il' 



CUlllNG IH] J^DI&0 PLANT. 



insects and caterpillars, that prey upon the valuable leaves, and 

 frequently disappoint the planter's expectations. 



All the intermediate shades of violet and purple may be 

 abtained from the mixture of red and blue, varying according 

 to the different proportions wherein these colours are applied. 

 There are, however, some few vegetable substances which yield 

 a violet or purple dye, without being combined with another 

 colour, and of these logwood is the most important. The 

 stately tree which furnishes this valuable article of commerce is 

 a native of the western world, having been first discovered in 







