THE UNIVERSE. ORGANIC DISCOVERIES. 287 



much the expedition of Ponce de Leon, in 1512, contri- 

 buted to the formation of more accurate opinions, and have 

 noticed that, in a memoir written by Sir Humphry Gilbert 

 between 1567 and 1576, the movement of the waters of the 

 Atlantic, from the Cape of Good Hope to the Banks of 

 Newfoundland, was treated according to views which agree 

 almost entirely with those of my excellent deceased friend, 

 Major Eennell. 



The knowledge of the oceanic currents was accompanied 

 by that of the great banks of sea-weed (Eucus natans), the 

 " oceanic meadows" which offer the remarkable spectacle of 

 the accumulation of a " social plant" over a surface almost 

 seven times greater than that of Prance. The " great Pucus 

 bank," the proper " Mar de Sargasso," extends between 19 

 and 34 of north latitude. Its principal axis is about 7 

 west of the Island of Corvo. The " lesser Pucus bank" is 

 situated in the space between the Bermudas and the 

 Bahamas. Winds and partial currents affect in different 

 years the position and extent of these Atlantic sea-weed 

 meadows, for the first description of which we are indebted to 

 Columbus. No other sea in either hemisphere shews an as- 

 semblage of social plants, on a similar scale of magnitude. ( 442 ) 



But the important epoch of the great geographical 

 discoveries, besides suddenly laying open an unknown 

 hemisphere of the terrestrial globe, also enlarged the view of 

 the regions of space, or to speak more distinctly, of the 

 visible celestial vault. As man, to quote a fine expression 

 of Garcilaso de la Vega, " in wandering to distant lands, 

 sees earth and stars change together, (*) so the advance 

 to the equator, on both sides of Africa, and in the western 

 hemisphere beyond the southern extremity of America, offered 



