60 ANCIENT HISTORY. [chap. iv. 



the Madeiras it might be worth while to inquire * ; but in the 

 meanwhile, supposing such materials for dyeing not to exist 

 there, it migbt not be improbable that Juba's traders had 

 found on the rocks of the Dezertas the plant which furnishes 

 us at this day with the most beautiful purples, the Orchil, or 

 Lachmus tinctorius. Tbat learned king, we know, was a 

 curious inquirer into the properties of plants, for it is men- 

 tioned by Pliny that it was he who discovered the Euphorbium 

 in the vicinity of Mount Atlas, and recommended it as a 

 collyrium for the eyes, and it seems likely enough that he 

 may have speculated on substituting the fine violet dye of the 

 vegetable Orchil for that of the animal Purpura. 



It is probable tbat the " Erythia," or Red Island of 

 Ptolemy, may have owed its name to the same circumstance 

 which gave their denomination to the " Purple Islands " of 

 Pliny, and may have been regarded as one of them. The 

 latitude of 29 degrees, assigned by Ptolemy to this island, 

 agrees best with that of the Salvages ; whilst the latitude of 

 3'2 degrees, which his tables give for the island " Paina" 

 (to be read, perhaps, Poina, i. e. Punica), corresponds per- 

 fectly with that of Madeira; and this ancient geographer 

 seems, therefore, only to have misplaced these islands, so far 

 as their longitude is concerned, in assigning to Erythia that 

 of 7 degrees, and to Poena of 5 degrees, an error apparently 

 due to his having fixed his first meridian, though the most 

 westerly of the Fortunate Isles, a few degrees too far to the 

 westward. 



* If any species of Manx or Buccinum can be found on these shores, it 

 should be carefully examined for the green juice described by ancient au- 

 thors, which, on exposure to air, turns first to lilac, and then to a red 

 purple. 



