ORDER TRACHELIPODA. 35 



possess it in a more pure state, and to extract it more 

 effectually, but obtained the colour from the smaller by- 

 grinding them in mills. He adds, that when the Pur- 

 purse were caught, the receptacle which contained the 

 dyeing-liquor was taken out and laid in salt for three 

 days; and that after a sufficiency of the matter had been 

 collected, it was boiled slowly in leaden vessels over a 

 gentle fire, the workman scumming off from time to 

 time the fleshy impurities. This process lasted ten 

 days, after which the liquor was tried by dipping wool 

 into it, and if the colour produced by it was defective, 

 the boiling was renewed. 



Other colouring-matters were employed sometimes 

 to economize, and at other times to vary the effect of the 

 liquors of the Purpurse. Among these Pliny enumerates 

 Fuciis ?7J077/2MS, or Archil, and the J nchusa tinctoria, or 

 Alkanet, both of which are still used as dyes. By these 

 and other means, the purple colour was made to assume 

 a variety of shades, some inclining more to the blue, 

 and others to the crimson. 



In modern times several attempts have been made to 

 obtain this dye; but the discovery of cochineal has ren- 

 dered it a matter of little import. 



In the year 1683, Mr. William Cole, of Bristol, being 

 at Minehead, was told of a person living at a seaport in 

 Ireland, who had made considerable gain by marking 

 with a delicate and durable crimson colour, fine linen 

 that was sent to him for that purpose, and that this 

 colour was made from some liquid substance taken from 

 a shell-fish. Mr. Cole, being a lover of natural history, 

 and having his curiosity thus excited, went in search of 

 these shell-fish, and, after trying various kinds without 

 success, he, at length, found considerable quantities of a 



