GENERAL FEATURES OF THE EARTH 11 



The pole of the land-hemisphere in this map is in the western 

 half of the British Channel ; and if this part, on a common globe, 

 be placed in the zenith, under the brass meridian, the horizon- 

 circle will then mark the line of division between the two hemi- 

 spheres. The portions of land in the water-hemisphere are the 

 extremity of South America below 25° S., and Australia, together 

 with .the islands of the East Indies, Pacific, and the Antarctic. 

 London and Paris are situated very near the centre of the land- 

 hemisphere. 



16. General arrangement of the Oceans and Continents.* — Oceans and 

 continents are the grander divisions of the earth's surface. But, 

 while the continents are separate areas, the oceans occupy one 

 continuous basin or channel. The waters surround the Antarctic 

 and stretch north in three prolongations, — the Atlantic, the Pacific, 

 and the Indian Oceans. The land is gathered about the Arctic, and 

 reaches south in two great continental masses, the occidental and 

 oriental ; but the latter, through Africa and Australia, has two 

 southern prolongations, making in all three, corresponding to the 

 three oceans. Thus the continents and oceans interlock, the former 

 narrowing southward, the latter northward. 



The Atlantic is the narrow ocean, its average breadth being 2800 

 miles. The Pacific is the broad ocean, being 6000 miles across, or 

 more than twice the breadth of the Atlantic. The Occident, or 

 America, is the narrow continent, about 2200 miles in average 

 breadth; the orient, the broad continent, 6000 miles. Each con- 

 tinent has, therefore, as regards size, its representative ocean. This 

 great difference of magnitude is an important fact in its bearing on 

 the earth's geological history. The Pacific Ocean, reckoning only 

 to 62° S., has an area of 62,000,000 square miles, or nine and a 

 half millions beyond the area of all the continents and islands. 



* In illustration of this part of the work, the reader is referred to the map at 

 the close of the volume. It is a Mercator's chart of the world, which, while it 

 exaggerates the polar regions, has the great advantage of giving correctly all 

 courses, that is, the bearings of places and coasts. The trends of lines ("trend" 

 means merely course or bearing) admit, therefore, of direct comparison upon 

 such a chart. It is important in addition that the globe should be carefully 

 studied in connection, in order to correct misapprehensions as to distances in 

 the higher latitudes, and appreciate the convergences between lines that have 

 the same compass-course. 



The low lands of the continents on this chart, or those below 800 feet in ele- 

 vation above the sea, are distinguished from the higher lands and plateaus by a 

 lighter shading, and the axes of the mountain-ranges are indicated by black 

 lines. The oceans are crossed by isothermal lines, which are explained beyond. 



