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THE ECONOMIC USES OF BROWN SEA- WEEDS. 



By Magnus Spence. 



(Deerness, Orkney.) 



I. The Kelp Industry was introduced into Orkney in 1720 as 

 a source of soda and potash used more particularly in the glass manu- 

 facture, corresponding to the pi'oduction of " barilla " on the Spanish 

 coast from sea-shore vegetation as Salsola and other Chenopods. 

 During the French war it constituted the great source of alkali 

 in this country, and prices rose considerably, the kelp-producing dis- 

 tricts enjoying great prosperity and a population of 20,000 being 

 maintained on it in Orkney alone. After the war, with free impor- 

 tation of alkali from other sources the industry deca^^ed ; and though 

 maintained as a source of iodine, it never really recovered its former 

 activity. Cheaper sources of iodine from Chili saltpetre residues, the 

 introduction of Le Blanc's salt-cake process for soda, and more 

 recently cheap supplies of potash salts from Stassfiirt, have destroyed 

 the industry ; though during the present war more sei'ious attempts 

 at sea-weed utilization have been made in other parts of the world, 

 plant being set up in British Columbia, as also previously in Japan. 

 Where vast quantities of weed are thrown up on the shore gratis, it 

 seems folly not to utilize the material, which consists wholly of 

 living tissue, with no hard or intractable skeletal portions, or masses 

 of woody tissue requiring complex apparatus for its recovery or 

 handling. On the other hand, to burn such organic material for the 

 sake of the salts is about as criminally foolish a proceeding as burn- 

 ing timber-trees for the sake of " potashes," and must be regarded as 

 the expression of the economic ideas of a past age. Dry distillation 

 has been more recently investigated in Sweden with encouraging 

 results {Nature, 1918, p. 374) : the product being illuminating gas, 

 acetic acid, methylated spirit, formic acid, acetone, etc., in addition 

 to the salts, improved iodine yield, and tars of the creosote type. 



Kelp-bu.rning is still carried on in a few localities in Orkney, but 

 several hindrances have reduced the quantity exported to a mere 

 fraction of what it once was : as reasons contributing to this, other 

 than cheaper sources of supply of alkali and iodine may be included ; 

 (1) the small price allowed to the workers by the proprietors ; (2) the 

 improved monetary condition of agriculture. About a hundred years 

 ago the amount manufactured in Orkney varied from 3000 to 3500 

 tons per annum, at from £7 to £10 per ton, thus bringing in a 

 considerable addition to the earnings of the people, and to the incomes 

 of the proprietors, who shared in the profits but not in the toil. The 

 kelp-burners received only £2 10s. per ton for their labour from the 

 landlord on whose sea-beach the sea-weed was driven : he exercised 

 some supervision over the work, generally by means of an agent who 

 advised as to kilns and purity of the kelp, and finally weighed the 

 finished product. The landlord provided the vessel for export ; but 

 those who remember the operations state that his price was often 

 £20 per ton — it rose to- £20 during the Napoleonic wars, and occa- 

 sionally between then and fifty years ago. 1£ so, there is little 

 JouBNAL OF Botany. — Vol. 56. [Decembek, 1918.] 2 a 



