132 SEAWEEDS. 



land. The duty lias since been taken off foreign barilla, 

 which is better adapted than kelp for glass-making, &c. ; 

 and now the principal use of the sea-weed ashes is for the 

 production of iodine. The properties of iodine were first 

 ascertained by Gay, Lussac, and Davy, about 1815. 

 Iodine exists in sea-water, and in sea-mollusks and weeds. 

 In the chemical process for obtaining it, it is discharged 

 from the kelp in a violet vapour, which is received into 

 glass baloons placed for the purpose, where it becomes 

 condensed into a solid black crystalline body. It is a 

 most valuable medicine in scrofula and all swellings, and 

 is of great use in photography. Martin Tupper alludes 

 to the medicinal property when he says : — 



• The sea-wort floating on the waves, or rolled up high along the shore, 

 1 e counted vile and useless, heaping on it names of contempt ; 

 Yet hath it gloriously triumphed, and man been humbled in his 



ignorance ; 

 For health is in 'the freshness of its savour, and it cumbereth the 



beach with wealth, 

 Comforting the tossings of pain with its violet-tinged essence, 

 And by its humble ashes enriching many proud." 



The waste left by the iodine is excellent for manure, 

 and the weeds are gathered in quantities to strew 

 upon the land in their simple state. Their value 

 is so well understood in the Isle of Arran that the factor 

 of the Duke of Hamilton allots a portion of the shore to 

 each person farming the adjacent land, and they carry 

 the w r eed inland for manure ; and also, in seasons of 

 scarcity, for food for the sheep and cattle. The F. vesi- 

 culosus is called Swine-tang in Gothland, and pigs are 



