504 PHYSICAL GEOGRAPHY. 



Beagle, along the south coast of South America, the glacier furthest from the pole, 

 descending to the sea coast, was found in latitude 46 50', in the Gulf of Penas ; but a 

 few miles to the north of this glacier, in the Laguna de San Rafael, some Spanish mis- 

 sionaries encountered icebergs, in a narrow arm of the sea, on the 22d of the month 

 corresponding with our June, and in a latitude answering to that of the Lake of Geneva ! 

 According to Von Buch, the most southern European glacier which comes down to the 

 sea is met with on the coast of Norway in latitude 67. This is more than 20 of latitude, 

 or 1230 miles nearer the North Pole than the Gulf of Penas is to the South. Mr. Darwin 

 puts the occurrence of this glacier in the southern hemisphere in a striking point of view, 

 by remarking, that it descends to the sea-coast within 7^ of latitude, or 450 miles of a 

 harbour, where three species of oliva, a valuta, and a terebra, are the commonest shells, 

 within less than 9 from where palms grow, within 4J of a region where the jaguar and 

 puma range over the plains, less than 2J from arborescent grasses, and, looking to the 

 westward in the same hemisphere, less than 2 from orchideous parasites, and within 

 1 of tree-ferns ! in South Georgia, an island discovered by Cook in his cruise of 1775, 

 in latitude 53, answering to the parallel which passes over the central counties of 

 England, the eternal snows come down to the sea-shore, while the curve of perpetual 

 congelation with us is at the height of more than 5000 feet. The perpetual snow does 

 not descend to the sea- level on the north of the equator till we arrive at the parallel 

 of 80, which is twenty-seven degrees nearer the pole than the point where the same fact 

 transpires in the southern hemisphere. This greater degree of cold was at first attributed 

 to an astronomical cause that of the acceleration of the earth's motion in its perihelion, 

 in consequence of which the sun is a shorter time, by nearly eight days, on the south, 

 than on the north side of the equator. But the true cause is undoubtedly geographical, 

 the great preponderence of the ocean in southern regions, which radiates less absolute 

 heat than dry land, and contributes to diminish the annual temperature of that part of 

 the globe. The same cause, however, operates to free the south-temperate zone from 

 " excessive climates," or those violent seasonal contrasts of temperature which the Anglo- 

 American and the inhabitants of Pekin experience, mild winters alternating with cold 

 summers. Port Jackson, in a latitude answering to that of Cairo, has the winter of that 

 city, and the summer of Marseilles. In Van Diemen's Land, corresponding nearly in 

 latitude to Rome, there is the summer of Paris and the winter of Naples. 



We may now cast a general glance over different districts of the globe which present 

 strongly -marked diversities of climate and productions, confining our attention chiefly to 

 the northern hemisphere. 



Equatorial and Hot Regions. These occupy a zone extending on each side of the 

 Une to a few degrees beyond the northern and southern tropic. As before remarked, the 

 mean temperature appears to be higher in situations verging towards the tropics than at 

 the equator ; and by this is to be understood the temperature of the air near the surface 

 of the earth, as determined by a thermometer, protected from radiation and every kind of 

 foreign influence. Thus the mean equatorial temperature is given by Humboldt at 

 811 ; but at Pondicherry, in latitude 11 55' north, it is at least 85. This is the region 

 of the finest spices, the sugar-cane, the palm and banana tribes. It includes the islands 

 and continent of Southern Asia, the middle and northern countries of Africa, and the 

 central parts of America. In its level midland portions, frost and snow are unknown, 

 and the uncivilised natives of various localities have often deemed the statement a fable 

 of the Europeans, that rivers became solidified by cold. In the well-watered countries, 

 the trees are covered with perpetual verdure, the fields exhibit a constant carpet of beau- 

 tiful and odoriferous flowers, and the only season resembling winter is the season of rain ; 

 but after the rains, the heat occasions noxious exhalations from the fruitful soils, and espe- 



