378 THE POPULAR SCIENCE MONTHLY. 



the venturous seaman against hidden rocks, sweeping ashore his 

 lifeless body and dismembered ship, also tear up great quantities 

 of this valuable weed from the ocean's bed and dash them in con- 

 tinuous bulwarks high up on the beach. Thus thrown ashore 

 during the winter and early spring is a mass of what the natives 

 call " deep-sea tangle," but which in the hands of the naturalist 

 is recognized as a mixture of two kinds of Algce, termed respective- 

 ly Laminaria digitata and Laminaria saccharina. In the spring 

 and fall the milder storms add the "tangle-top" to the winter 

 harvest. The tangle-top, as its name implies, consists of the tops 

 or fronds of the same plants whose stems compose the " tangle " 

 proper. These self -gathered masses constitute the greater bulk 

 and the more valuable part of the annual yield. Together they 

 are known as " drift-weed," as opposed to three varieties of Fuci 

 (more commonly known as wracks) which grow on the rocks in 

 that area covered by the rise and fall of the tides, and which, 

 from the manner of their gathering, take the name of " cut- 

 weed." 



Recourse must be had at this point to chemical analysis to 

 reveal some useful ingredient which may justify this wet, salty, 

 ill-odored mass of vegetable matter being dignified by the name 

 of a crop. The analyses of the several species of Laminaria and 

 Fuci show considerable variations ; it may, however, be taken 

 that of the ordinary mixed mass of wet tangle and cut-weed about 

 eighty per cent is water, fifteen per cent organic matter, and five 

 per cent ash or mineral matter. In the same way it may be ad- 

 mitted that one hundred pounds of the ash will contain, approxi- 

 mately, twenty pounds of insoluble material, fifty pounds of alka- 

 line carbonates and chlorides, twenty-two pounds of potash and 

 soda, G"5 pounds of sulphurio acid in combination, and 1'5 pound 

 of iodine in combination as iodides of potassium, sodium, etc. 

 One hundred and fifty years ago such an analysis had never been 

 made, nor would it have possessed any of its present suggestive- 

 ness, for at that time iodine had not yet been discovered, and the 

 burning of sea-weed for its ashes was practiced to but a very lim- 

 ited extent. It required the pressure placed upon the soap-makers 

 of France and England by the wars of the great Napoleon to force 

 practical and wide-spread attention to the ashes of sea-weed. In 

 virtue of that pressure the foreign supply of soda and potash salts 

 in both of those countries was entirely cut off, and every domestic 

 substance was ransacked for its contents of alkalies. This gave 

 rise to that general movement among the Scotch and Irish peas- 

 antry which resulted in the annual burning of the sea-weed har- 

 vest, and the introduction of a new commercial body under the 

 name of varec or kelp. 



Though the absolute yield of the alkali salts was small (about 



