Chapter XVIII 



ALGAL UTILIZATION 



Seaweeds have been used by man for as long as we have any written 

 records and their use probably extends to even earlier times. In 

 early years, apart from being used as food, they did not form part of 

 any major industry, and it was not until the seventeenth century 

 that the first industry, the kelp trade, developed. Although the kelp 

 trade is now an industry of the past (cf. p. 13), nevertheless it as- 

 sumed such great importance that a brief account is not amiss. The 

 word kelp itself originally referred to the burnt ash of the brown 

 seaweeds and only subsequently became applied to the actual 

 weeds. The algae primarily used in Europe were the species of 

 Laminaria and Fucus with Ascophyllum nodosum. The former was 

 collected as cast weed whereas the two latter were cut off the rocks 

 on which they were growing. Initially the ash was produced for the 

 soda that it contained and then later it was used as a source of 

 iodine (see p. 13). When the weed had been collected it was al- 

 lowed to dry, often on special stone walls, and then when dry it was 

 burnt in circular or cyUndrical kilns. The burning went on until 

 the worker had a cake of ash fifteen^to twenty-four inches thick. In 

 the early years when the ash was used as a source of soda the tem- 

 perature did not matter, but in the later years when iodine was 

 required, the temperature could not be allowed to rise too high 

 because much of the iodine then volatiUzed and escaped. The type 

 of weed also was of some importance. Fucus species and Asco- 

 phyllum are richer in soda and were thus favoured in the early years, 

 whilst laminarians are richer in iodine and were therefore more in 

 demand in the later years. 



In the latter half of the nineteenth century new processes were 

 evolved in order to eliminate the loss of iodine and also, if possible, 

 to utihze both stipe and blade, particularly the stipes which are cast 

 ashore in great quantity in the winter. There was in addition the 



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