34 BRITISH SEA-WEEDS. 



wrack, or vraich, a term applied in a general sense to 

 Sea-weeds, is collected for manure or fuel, and the fer- 

 tility of certain localities, as for instance the Channel 

 Islands, is due to the facility with which this can be ob- 

 tained. In Jersey there are very stringent laws as to 

 the season when the vraich may be cut, and during the 

 prescribed time every available man, woman, and con- 

 veyance is devoted to the service. The whole island 

 reeks of vraich, and carts of all sorts and sizes, heavily 

 laden with it, are to be met at every turn. The little 

 island horses seem to thoroughly understand the busi- 

 ness, and pick their way over the rocks with carts be- 

 hind them in a manner perfectly astounding to the 

 uninitiated beholder. 



All the large weeds of the Olive series were formerly 

 very extensively and profitably used in the manufacture 

 of kelp, then one of the chief ingredients of glass and 

 soap, but which has since been superseded by cheaper 

 alkalies. The chemical substances iodine and mannite 

 are obtained from Sea- weeds; and a species of Gracilaria, 

 mixed in most cases with Laurencia obtusa, is used me- 

 dicinally under the name of Corsican moss. 



Chondrus crispus and some other species yield a 

 gelatine said to be a remedy for consumption, and 

 which is at any rate sufficiently good to be used in 

 the preparation of blancmange. In China a cement 

 of equal strength with gum and glue is derived from 

 another species of Gracilaria. Several British species 

 are reputed to be eatable, but none of them, with the 

 exception, perhaps, of the Porphyra, which yield c sloke' 

 or ' laver/ are very palatable. Chinese birds'-nest, which 

 is composed of an Alga, is, however, a dainty delicacy 

 when eaten in soup. 



