62 INTRODUCTION. 



manufactured, from which not above 0,000/. are realized, 

 after deducting the wages of the kelpers and the expense of 

 necessary a])paratus. This small remuneration, however, is 

 owing in part to the Highlanders^ perseverance in manu- 

 facturing their kelp from the yelloiv wrack {Facus oiodosus), 

 which, from growing in shallow water, and beijig less 

 thoroughly a marine plant, yields much less iodine than the 

 kelp manufactured from the hlack irrach, such as Laminana 

 digifata, the Great-stemmed Tangle ; and Fkcus serratus, 

 the Serrated Sea-weed. Irish kelp prepared from drift-iveed 

 from deep water, is rich in iodine, yielding above twelve 

 pounds per ton, and, consequently, carefully and honestly 

 prepared Irish kelp brought in some cases 10/. per ton, 

 in 1845, when Highland kelp would not bring above the 

 half of that sum. The rise which, after twenty vears of 

 depression, took place lately in the price of kelp, was owing 

 to a great additional demand for iodine. 



"Who knows what virtues we may yet discover in the 

 drapery of the deep ? The book of nature is like tlie book 

 of grace, the wonders they contain must be "sought out.^^ 

 Iodine, it would appear, contributes in some way to the health 

 of marine plants, for they all have the power of extracting 

 it from the waters of the deep. Or is this power given them 



