36ff VEGETABLE SUBSTANCES. 



tinning beyond the supply, when, in 1730, the captain 

 of an English vessel discovered it growing in the Cape 

 de Verd Islands. It was found in so great abundance 

 that in a few days 50,000 pounds of moss were col- 

 lected from only two of the islands. This orchella 

 was larger, longer, and richer in colouring matter 

 than that of the Canaries, perhaps in consequence of 

 its having grown undisturbed, while the other was 

 exhausted by being collected every year. A few years 

 after this time Mr. Adanson found the orchella lichen 

 in Magdalen Island, near Senegal, where the rocks 

 were covered with the prolific plant. 



The orchella lichen grows upright, either in single 

 or double stems of about two inches in height. These 

 are cylindrical, and internally white. When old, the 

 plant is crowned with a round, or sometimes flat 

 button. Its colour varies from white to a dark grey. 

 It is imported as it is gathered, without receiving any 

 previous preparation. In the different countries to 

 which it is imported it undergoes some process before 

 it can be employed as a dye. The manner of pre- 

 paring this in Florence, as described by Mecheli, and 

 quoted by Hellot, is, first to reduce the plant to a fine 

 powder, which is passed through a sieve ; a chemical 

 preparation of soda and other ingredients is then 

 added. The mixture is daily stirred until it assumes 

 a dove colour. It is then put into a wooden cask, 

 and lime-water, or a solution of gypsum, is poured 

 upon it until its surface is covered, in which state it 

 is preserved. After a preparation nearly similar to 

 this, the French make it into a kind of paste, which 

 they designate biseille en pate. The colour which is 

 obtained from it in England is evaporated to dryness, 

 and assumes the form of a deep red powder, known 

 in the shops under the name of cudbear. Prepared 

 orchella usually is known under the general name of 

 archil. An infusion of this is of a crimson colour, 



