72 



ALG.E. 



seem to grow without being fixed to a spot. The 

 general colour of sea-weeds is olive-brown or olive- 

 green, but they are often of a beautiful red or green 

 colour, and look well when dried and fixed on white 

 paper. They easily become dry and shrivelled by 

 exposure to the air, but they can afterwards be revived 

 by being put into water. Botanists take advantage 



the ocean by the aid of small vesicles full of air, 

 which nature has wisely placed at the base of each 

 leaf. 



Sea-weeds grow with amazing rapidity. A proof 

 of this may be given in the case of the Carr Rock, a 

 sunken rock near the mouth of the Frith of Forth, 

 which was dressed with the pick and chisel, and com- 



of this property in making their collections ; for even | pletely freed from sea-weeds for the purpose of erect- 

 although the plants should have been withered in con- j ing a stone beacon. Operations were suspended in 



sequence of having been gathered for a long time, 

 they can be made to resume their fresh appearance 

 before being subjected to pressure for the purpose of 

 being properly dried. 



In almost all moist places we find some of the 

 species belonging to this extensive family, which in- 

 cludes not only the sea-weeds or fuel, properly so 

 called, but also many plants which exist in fresh 

 water. Some of these plants are found even in hot 

 springs ; thus the Ulva thermalis grows in the hot 

 springs of Gastein, which have a temperature of 1 J 7 

 of Fahrenheit's thermometer. Under this family are 

 included some plants of the most minute and micro- 

 scopic nature, and others of the most enormous size ; 



from the green slimy matter covering the surface o 

 wet stones to the gigantic fuel which grow from th 

 greatest depths of the ocean. Some of the plants are 

 nearly allied to the lowest orders of the animal king- 

 dom, and the gradation is so gradual that no distinci 

 line of demarcation can be traced. The difficulty o: 

 distinguishing some of the algae from the zoophytic 

 members of the animal kingdom may be shown by 

 the fact that several species which used to be re- 

 ferred to the former, have lately been transferred to 

 the latter ; and many naturalists have even gone the 

 length of supposing that many of the species are 

 plants during one part of their existence, and animals 

 during another. 



Though the plants belonging to this family, are 

 often passed over as of little importance, we find 

 many of them distinguished for their beauty as well as 

 their utility, contributing to the wants of man both in 

 an economical and medical point of view. They have 

 engaged the attention of many eminent botanists, and 

 several valuable works have been published on the 

 subject. We would particularly refer our readers to 

 the beautiful delineations and excellent descriptions 

 from the pen of Mr. Turner in his splendid work on 

 the Fuci, also to Dr. Greville's Treatise on the 

 British Algae, and to the excellent arrangement 

 given by Dr. Hooker in the fifth volume of the 

 English Flora. 



Algae exist in all parts of the ocean, but they 

 vary in different regions. Those found in the Medi- 

 terranean, for instance, are different from those met 

 with in the Red Sea, while the latter do not resemble 

 those of the West Indian Sea. Each great division 

 has its peculiar marine vegetation, answering wise 

 purposes in the economy of nature, and contributing 

 doubtless in many ways to the comfort of the animals 

 which inhabit the pathless depths of the ocean. 



Some of the sea-weeds attain a great length. Thus 

 the Chorda filum found in the North Seas, and grow- 

 ing so abundantly in some of the Orkney bays as to 

 impede the passage of boats, attains a length of thirty 

 or forty feet. But this is greatly exceeded by a 

 species of Maciocystes, which is stated to have been 

 met with in the South American seas, 1000 or 1500 

 feet long. This sea-weed, is of enormous length, 

 and has much thinness of stem. It is supported in 



the month of November, and were resumed again in 

 the month of May ; and although the winter had been 

 very severe, still the rock was found again completely 

 covered with sea-weeds, some of them six feet long. 



An object which has particularly attracted the 

 attention of navigators, is the Gulf-weed, which 

 consists of two or three species of sea-weeds 

 (sargasso), found floating in great abundance on 

 each side of the Equator, in the Atlantic, Pacific, 

 and Indian oceans.. The name of Gulf-weed was 

 given from the supposition, which has been proved to 

 be erroneous, that these sea-plants grew in the Gulf 

 of Mexico, and were carried across the Atlantic by 

 the gulf stream. From the great accumulation of 



floating sea-weeds between the eighteenth and thirty- 



second parallels of north latitude and the twenty-fifth 

 and fortieth meridians of west longitude, the Portu- 

 guese have denominated this part of the ocean the 

 sea of sea-weeds. Naturalists are as yet ignorant of 

 the manner in which these floating sea-weeds are 

 detached from the bottom of the ocean, and of the 

 reason why they are confined to particular regions. 

 In the economy of nature they seem to be useful in 

 affording food and shelter to fishes and molluscous 

 animals, and they probably tend to maintain the 

 purity of the ocean. 



Fucus vesiculosua. 



From several species of sea-weeds, more especially 

 the Fucus vcsiculosus, nodosus, and serratus, as well 

 as the Chorda filum, and several species of Laminaria, 



valuable article of commerce is obtained, deno- 

 minated kelp. This substance, which consists chiefly 

 of an impure carbonate of soda, is procured by burn- 

 ng sea-weeds, and is employed in the manufacture 

 of glass and soap. The practice of collecting the 

 ashes of the sea-weeds was introduced into Scotland 

 n the year 1 722. It had been carried on some time 

 >revious to that in France and England. The Orkneys 

 the first part of Scotland where kelp was manu- 

 uctured, and though the innovation was resisted at 



