285 

 THE MANUFACTURE OF KELP. 



BY EDWARD C. C. STANFORD F.C.S. 



The manufacture of kelp, or the burning of sea-weed to obtain its ash, 

 was commenced about the middle of last century, and was first carried, 

 on for the value of the carbonate of soda contained in it, but when the high 

 war duties were taken off foreign barilla and salt, kelp, for which the 

 demand had been very great, deteriorated in value and was scarcely worth 

 making. The carbonate of soda is never now extracted from this source ; 

 the yield was always small, and it is now obtained so cheaply from common 

 salt. At the beginning of the present century, during the war, Highland 

 kelp realised from 201. to 221. per ton. M'Oulloch states that the kelp shores 

 of the island of North Uist alone let for 7,O00Z. per annum : that the 

 Hebrides afforded 6,000 tons of kelp per annum, and the total produce 

 of Scotland was 20,000 tons per annum, an amount which has never 

 been manufactured since throughout Great Britian. When the duty 

 was taken off barilla, Highland kelp tell to Zl. per ton, and very little 

 was produced. In 1812, iodine was discovered by M. Courtois manu- 

 facturer of saltpetre, in Paris. The discovery was announced by M. 

 Desormes, at the meeting of the French Institute on the 19th of November, 

 1813. The attention of the discoverer was first arrested by the destruction 

 of his copper pans employed in the decomposition of nitrate of lime by the 

 alkaline lye of the kelp. Having constantly observed this phenomenon, 

 he attempted its solution, and after much patient research, and many 

 failures, he succeeded in tracing the effect to the cause, and in preparing 

 iodine in a state of purity. The manufacture of saltpetre having failed, 

 Courtois took to the preparation of iodine as a source of profit, but in 

 consequence of its then very limited application, the enterprise was 

 unsuccessful, and the project was abandoned, but it was taken up after- 

 wards by MM. Cournerie, at Cherbourg, and there are still iodine works 

 in that neighbourhood. Although, like many inventors, Courtois gained 

 nothing by his discovery ; a late distinguished English chemist turned it 

 to good account, and made a large sum of money by buying up all the 

 mother liquors of the Scotch kelp works, and extracting the new body. 

 This element, iodine, has since been found widely diffused in nature, 

 partictdarly in some aluminous slates, in varieties of coal and turf, in 

 Chili nitre, in the silver and mercury ores of Mexico, and also recently by 

 M. Chatin, though his conclusions are doubted by some chemists, in fresh- 

 water plants, rain water, and dew. It exists also in many mineral waters, 

 some of which owe their medicinal effects to its presence, and in cod liver 

 oil. Some marine animals also contain it, oysters and sponges for instance. 

 Kelp, however, is the only commercial source for its production, and the 

 immense value of iodine, in photography and medicine particularly, has 

 given an impulse to the manufacture of kelp, which renders it by far the 

 most important of all the applications of seaweed. 



As at present carried on, it has many disadvantages ; these are well- 



