30 THE OCEAN. 



soda, important in the manufacture of soap and of 

 glass, is the produce of these "worthless" weeds. 

 Some years ago, the coasts and islands of Scotland 

 yielded 20,000 tons of this valuable substance an- 

 nually, which was worth ten pounds sterling per ton ; 

 but through the increased consumption of barilla, an 

 allvali imported from Spain, it has somewhat dimin- 

 ished. The autumnal storms detach large quantities 

 of Algce (a general name applied to all the sea-weeds), 

 which are washed ashore. The inhabitants of the 

 coast, aware of their value, hurry down to secure the 

 riches thus freely presented, and either cast them 

 on their fields as a valuable manure, or burn them 

 into kelp. In Scotland, the kelp-kiln is nothing but 

 a round pit, dug in the sand or earth on the beach, 

 and surrounded by a few loose stones. In the morn- 

 ing a fire is kindled in this pit, generally with the aid 

 of turf or peat. The fire is gradually fed with sea- 

 weed, in such a state of dryness that it will merely 

 burn. In the course of the day, the furnace becomes 

 nearly full of melted matter, and iron rakes are then 

 drawn rapidly backward and forward through the mass 

 to compact it, or bring the whole into an equal state 

 of fusion. It is then allowed to cool, and having been 

 taken out and broken to pieces, it is carried to the 

 storehouse to be shipped for market. The general 

 yield of this alkali is one-fifth of the weight of the 

 ashes from weeds promiscuously collected ; but from 

 one species, the Sea-wrack, or Black-tang (Fucus vesi- 

 culosus), one of the most abundant on our coast, the 

 ashes yield half their weight of alkali. The Sea- 

 wrack is of a dark-olive hue, bearing long, flat, and 



