212 THE OCEAN. 



considered peculiarly subject to tempests ; while the 

 almost continual prevalence of westerly winds, joined 

 to the severity of the climate, has always given a 

 character of difficulty and hazard to the passage from 

 the one Ocean to the other. 



In approaching the extreme point of South America, 

 navigators have been struck with the extraordinary 

 size of a floating seaweed, the Macrocystes pyrifera of 

 botanists. It consists of a smooth round stem, com- 

 monly from 500 to 1,000 feet in length : Foster 

 mentions one which was 800 feet, and some speci- 

 mens are reported even to attain the enormous 

 dimensions of 1,500 feet. From the stem grow a 

 great number of pear-shaped air-vessels, which end 

 in long, flat, wrinkled fronds of a semi-transparent 

 brown hue. I liave already spoken of the Gulf-weed 

 {Sargassum vulgare), as being met with in particular 

 parts of tlie Atlantic : similar collections of it occur 

 also in these and other seas, and much mystery seems 

 to lie about its origin and mode of growth. From 

 specimens having been found with roots, it appears 

 certain that in a living state it is attached to the 

 bottom, whence it is not impossible that it may be 

 detached spontaneously at a certain period of its 

 growth, that the seed-vessels may be perfected by 

 exposure to light and air. Near the shores sea- weeds 

 are found so uniformly growing to rocks as to form a 

 very valuable indication of the presence of hidden 

 dangers. These appear to be chiefly of the former 

 kind. 



To these remote and inhospitable seas many vessels 

 are annually despatched from this country, as well as^ 



