1834.] TIERRA DEL FUEGO AND THE WEST COAST. if? 



latitude of 40, with Madrid) grapes and figs ripen, but are not common , 

 olives seldom ripen even partially, and oranges not at all. These fruits, 

 in corresponding latitudes in Europe, are well known to succeed to 

 perfection ; and even in this continent, at the Rio Negro, under nearly 

 the same parallel with Valdivia, sweet potatoes (convolvulus) are 

 cultivated ; and grapes, figs, olives, oranges, water and musk melons, 

 produce abundant fruit. Although the humid and equable climate of 

 Chiloe, and of the coast northward and southward of it, is so unfavour- 

 able to our fruits, yet the native forests, from lat. 45 to 38, almost 

 rival in luxuriance those of the glowing intertropical regions. Stately 

 trees of many kinds, with smooth and highly coloured barks, are loaded 

 by parasitical monocotyledonous plants ; large and elegant ferns are 

 numerous, and arborescent grasses entwine the trees into one entangled 

 mass to the height of thirty or forty feet above the ground. Palm-trees 

 grow in lat. 37 ; an arborescent grass, very like a bamboo, in 40 ; and 

 another closely allied kind, of great length, but not erect, flourishes 

 even as far south as 45 S. 



An equable climate, evidently due to the large area of sea compared 

 with the land, seems to extend over the greater part of the southern 

 hemisphere ; and as a consequence, the vegetation partakes of a semi- 

 tropical character. Tree-ferns thrive luxuriantly in Van Diemen's Land 

 (lat. 45), and I measured one trunk no less than six feet in circum- 

 ference. An arborescent fern was found by Forster in New Zealand 

 in 46, where orchideous plants are parasitical on the trees. In the 

 Auckland Islands, ferns, according to Dr. Dieffenbach,* have trunks so 

 thick and high that they may be almost called tree-ferns ; and in these 

 islands, and even as far south as lat. 55 in the Macquarrie Islands, 

 parrots abound. 



On the Height of the Snow-line, and on the Descent of the Glaciers, 

 in South America. For the detailed authorities for the following table, 

 I must refer to the former edition : 



Equatorial region ; mean result 15-748 Humboldt. 



Bolivia, lat. 16 to 18 S. . . 17,000 Pentland. 



Central Chile, lat. 33 S. . . 14.500 to 15,000 Gillies, and the Author. 



Chiloe, lat. 41 to 43 S. . . 6,000 Officers of the Beagle, and 



the Author. 

 Tierra del Fuego, 54 S. . . . 3,500 to 4,000 King. 



As the height of the plane of perpetual snow seems chiefly to be 

 determined by the extreme heat of the summer, rather than by the 

 mean temperature of the year, we ought not to be surprised at its 

 descent in the Strait of Magellan, where the summer is so cool, to 

 only 3,500 or 4,000 feet above the level of the sea ; although in Norway 

 we must travel to between lat. 67 and 70 N., that is, about 14 nearer 

 the pole, to meet with perpetual snow at this low level. The difference 



* See the German Translation of this Journal; and for the other facts 

 Mr. Brown's Appendix to Flinders's Voyage. 



