56 FLOATING SEAWEEDS. 
said by Columbus to resemble extensive meadows, 
and which inspired with terror the crew of the Santa 
Maria. From a comparison of numerous journals 
it appears that there are two such fields of seaweed 
in the Atlantic. The largest oecurs a little to the 
west of the meridian of Fayal, one of the Azores, 
between 25° and 36° of latitude. The tempera- 
ture of the ocean there is between 60°8° and 68° ; 
and the north-west winds, which blow sometimes 
with impetuosity, drive floating islands of those 
weeds into low latitudes, as far as the parallels of 
24° and even 20°. Vessels returning to Europe 
from Monte Video, or the Cape of Good Hope, pass 
through this marine meadow, which the Spanish 
pilots consider as lying half-way between the West 
Indies and the Canaries. The other section is not so 
well known, and occupies a smaller space between 
lat. 22° and 26° of N., two hundred and seventy-six 
miles eastward of the Bahama Islands. 
Although a species of seaweed, the Lamznaria py- 
rifera of Lamouroux, has been observed with stems 
850 feet in length, and although the growth of these 
plants is exceedingly rapid, it is yet certain that in 
those seas the fuci are not fixed to the bottom, but 
float in detached parcels at the surface. In this state 
vegetation, it is obvious, cannot continue longer than 
in the branch of a tree separated from the trunk ; 
and it may therefore be supposed, that floating masses 
of these weeds occurring for ages in the same posi- 
tion owe their origin to submarine rocks, which con- 
tinually supply what has been carried off by the equi- 
noctial currents. But the causes by which these 
plants are detached are not yet sufficiently known, 
although the author just named has shown that fuci 
