49. Alaska.—To the west of northern Canada is Alaska, which now belongs to the United States. The Russians first settled Alaska and held it until the United States bought it in 1867. If you look on the map, you will see in Alaska a great river, the Yukon. Gold is now found along this river and steamers go up it every summer, all the way across Alaska and into Canada. With all its great size, Alaska has fewer people in it than you will find in any one of many small cities in the United States. This is because much of Alaska is so cold that very few settlers have gone there.
50. Greenland and its is cold and snowy, but it has a better climate than has Greenland. Greenland is nearly covered by a great sheet of ice. (Fig. 31.) No trees ever grow there at all. For hundreds and hundreds of miles noth ing can be seen but ice and snow. The snow lies there year after year, and finally packs into solid ice. This ice slowly creeps down the slope of the land toward the ocean, pushes itself into the sea, and finally breaks off in great blocks and floats away. While a mass of ice is creeping over the land we call it a glacier; when a piece of it floats in the sea we call it an iceberg. The icebergs that float past the codfishermen on the coast of Labrador and Newfoundland (Sec.
12), and finally melt away in the warmer water to the southward, have floated down from Greenland in the far north.
51. Different kinds of though the northern part of North America is so cold, further to the south is a large region having cold winters and warm summers. This covers all the central part of the continent, and in this region most of the people live. As we travel south the climate grows warmer, until in Central America we find there is never frost except on high mountains, and the trees are green all the year. Why are Greenland and Alaska so cold, while Central America is so hot? Because the sun does not rise very high in the Greenland sky. You know how cool it is, even in summer, in the early morning when the sun is not very high, and how hot it is at noon. Even at noon in summer, the sun is low in the sky in the far north. But in the far south, in Central America, the sun climbs high in the sky all the year round, so that the climate is very hot in summer, and is warm even in winter. Find another continent (Fig. 40) which you think would have a hot climate in one part and a climate in another part.