Courtois, Bernard (1813). «Découverte d'une substance nouvelle dans le Vareck». Annales de chimie. 88: 304 In French, seaweed that had been washed onto the shore was called "varec", "varech", or "vareck", whence the English word "wrack". Later, "varec" also referred to the ashes of such seaweed: The ashes were used as a source of iodine and salts of sodium and potassium.
