LESSON VI.

DESCRIPTION OF THE EARTH’S SURFACE.—DIVISION OF IT INTO ZONES.—TORRID, TEMPERATE AND ARCTIC ZONES.—THE FIVE GREAT CONTINENTS.—RELATIVE DIMENSIONS OF AMERICA, EUROPE, ASIA, AFRICA AND AUSTRALIA.

§ 32. Having learned the relation of our Earth to the Sun and the Planets, it will be well to acquaint ourselves with the principal objects on its surfaces.—What theInteriorof our Earth consists of, we have as yet no idea, because we have not yet been able to penetrate deeper than a few hundred feet; and this is, in proportion to the Earth’s Diameter, little more than nothing. But as regards her surface, we know that it consists partly of land and partly of water. Little more than one fourth of the Earth’s surface is covered with land; all the rest is water.—The great lands are calledContinents; the great waters are calledOceans. Smaller portions of land surrounded on all sides by water, are calledIslands. Smaller bodies of water surrounded by land are calledLakes.

§ 33. The land on our Earth is divided into Five Continents: America, Europe, Asia, Africa and Australia.—These, however, are not all of the same extent. Europe is the smallest of them. America and Asia are the greatest.

The adjoining Plate No.XI, will give you an idea of the proportion of land and water on our Earth, and of the relative extent of the Five Continents.Fig. I represents the surface of the Earth divided into land and water. Were all land on our Earth put together in a circle, and the water placed round it, then the land would only fill the inner circle, the water occupying the surrounding ring, a space nearly four times as large as the circle. Fig. II, III, IV, V and VI represent the comparative surfaces of America, Europe, Asia, Africa and Australia. Fig. VII represents the comparative surface of the Moon.

The adjoining Plate No.XI, will give you an idea of the proportion of land and water on our Earth, and of the relative extent of the Five Continents.

Fig. I represents the surface of the Earth divided into land and water. Were all land on our Earth put together in a circle, and the water placed round it, then the land would only fill the inner circle, the water occupying the surrounding ring, a space nearly four times as large as the circle. Fig. II, III, IV, V and VI represent the comparative surfaces of America, Europe, Asia, Africa and Australia. Fig. VII represents the comparative surface of the Moon.

Upon close inspection of these figures you will perceive;

1. That the extent of America and Asia are nearly equal; but that each of these Continents is several times larger than either Europe or Australia.

2. That the next greatest portion of our Globe isAfrica, which is more than three times larger than Europe.

3. That Europe is the smallest Continent of our globe.

4. That the whole surface of the Moon would not be more than enough to cover either America or Asia.

No. XI.Fig. 1.THE OCEANTHE LANDFig. 2.EUROPEFig. 3.ASIAFig. 4.AFRICAFig. 5.AMERICAFig. 6.AUSTRALIAFig 7.THE MOON’SSURFACEGeographical Miles.

No. XI.

Fig. 1.THE OCEANTHE LANDFig. 2.EUROPEFig. 3.ASIAFig. 4.AFRICAFig. 5.AMERICAFig. 6.AUSTRALIAFig 7.THE MOON’SSURFACEGeographical Miles.

No. XII.Fig. 1.THE WHOLE TORRID ZONEComparative Extentof theTWO TEMPERATEZONESComparativeEXTENTof theTWO ARCTICZONESFig. 2.Comparative Extentof one of theWHOLE TORRIDZONEFig. 3.Comparative Extentof one of theTWO TEMPERATEZONESFig. 4.ONEof theARCTICZONESFig. 5.Comparative Extentof theWHOLE LANDon ourGLOBE

No. XII.

Fig. 1.THE WHOLE TORRID ZONEComparative Extentof theTWO TEMPERATEZONESComparativeEXTENTof theTWO ARCTICZONESFig. 2.Comparative Extentof one of theWHOLE TORRIDZONEFig. 3.Comparative Extentof one of theTWO TEMPERATEZONESFig. 4.ONEof theARCTICZONESFig. 5.Comparative Extentof theWHOLE LANDon ourGLOBE

No. XIII.

No. XIV.Square contentsof the TwoTEMPERATEZONES.Square contentsof theWHOLE TORRIDZONE.Square contentsof the TwoARCTIC ZONES.The whole surfaceof the fiveGREAT CONTINENTSon ourGLOBECompared to one of the twoTEMPERATE ZONES.

No. XIV.

Square contentsof the TwoTEMPERATEZONES.Square contentsof theWHOLE TORRIDZONE.Square contentsof the TwoARCTIC ZONES.The whole surfaceof the fiveGREAT CONTINENTSon ourGLOBECompared to one of the twoTEMPERATE ZONES.

§ 34. The Earth’s surface is not throughout equally illumined or heated by the Sun; because the Sun’s rays strike some portions of the Earth more perpendicular than others. Our Earth, therefore, is divided intoClimatesorZones, which you will understand better from PlateXII.

You will see from it that the Sun’s rays are perpendicular to the central part of the Earth’s surface; but that toward the extremities of the Earth’s Diameter these rays strike us more and moreobliquely. The greatest heat, therefore, must be felt by the people living between the two circles EF and IK. The circle GH, which is exposed to the perpendicular rays, is termed theEquator; and the two circles EF and IK,which are at equal distance from the Equator, are called Tropic Circles. The whole surface included by these two circles is called thetorrid Zone. The space between either of the circles CD and EF, or IK and LM, is called atemperate Zone; because the Sun’s rays striking these portions neither perpendicular nor very obliquely, their inhabitants suffer neither great heat nor cold. In one of these Zones are situated the United States of America and the greater portion of Europe. Beyond them, toward the extremities of the Diameter AB, are the twoicyorarcticzones. The Sun’s rays strike them very obliquely; which is the cause of their being almost continually covered with ice or snow.

The two circles, CD and LM, are calledPolarcircles; and the two extremities, A and B, of the Earth’s Diameter, situated in those regions, are calledthe Poles. A is called theNorth-Poleand B theSouth-Poleof the Earth.

§ 35. The different zones of which we have just spoken, are not equal to one another. PlateXIII, will show their relative extent.

Fig. I represents the surface of the Earth divided proportionally into its three zones: thetorrid, thetemperateand thearctic. The inner circle represents both the arctic zones; the yellow ring b, which surrounds it, represents the united extent of the two temperate zones; and the outmost red ring, the whole of the twotorrid zones.Fig. II represents separately the whole torrid zone;—Fig. III one of the temperate zones;—Fig. IV one of the arctic zones; and Fig. V the whole extent of land on our globe.The next Plate, No. XIV, represents the comparative surfaces of these zones, drawn separately in form of squares; and the last figure on that Plate, shows the extent of the five continents, compared to one of the temperate zones.

Fig. II represents separately the whole torrid zone;—Fig. III one of the temperate zones;—Fig. IV one of the arctic zones; and Fig. V the whole extent of land on our globe.

The next Plate, No. XIV, represents the comparative surfaces of these zones, drawn separately in form of squares; and the last figure on that Plate, shows the extent of the five continents, compared to one of the temperate zones.

No. XV.Fig. 1.Fig. 2.Fig. 3.Fig. 4.Fig. 5.Fig. 6.

No. XV.

Fig. 1.Fig. 2.Fig. 3.Fig. 4.Fig. 5.Fig. 6.

You will observe from a close inspection of these figures, that the whole extent of land on our globe is nearly equal to that of a temperate zone; and that if it were possible to unite America, Europe, Asia, Africa and Australia into one, their united extent would not yet fill one of the temperate zones! You will also perceive that the two temperate zones occupy together the greatest portion of the Earth’s surface, and that the arctic zones occupy comparatively the smallest.

RECAPITULATION OF LESSON VI.

QUESTIONS.

[§ 32.] Do we know anything about the Interior of our Earth? Why not? What does the surface of our Earth consist of? What proportion does the land bear to the water? What are the great lands called? What, the great waters? What are smaller portions of land, surrounded by water, called? What, small portions of water, surrounded by land?

[§ 33.] Into how many continents is all the land of our Globe divided? What are they? Are all the continents of our globe of the same extent? Which is the smallest of them? Which are the largest? Explain Plate, No. XI.

What proportion does the extent of America bear to that of Asia? What relation do these continents bear to Europe or Australia? What is the next greatest portion on our globe? Which continent is the smallest? What relation does the surface of the Moon bear to America or Asia?

[§ 34.] Is the whole Earth equally illumined or heated by the Sun? Why not? What is, therefore, the surface of our Earth divided into? Upon what portion of our Earth do the Sun’s rays fall perpendicular? What portion do they strike more obliquely? What people, therefore, will experience the greatest heat?

[The pupil ought now to explain PlateXII. The elder pupils ought to draw a sphere with the Equator, the tropic and arctic circles. They ought also to draw the Diameter of the Earth, and indicate the North and South Pole.]

[§ 35.] If you compare the whole extent of land on our globe to the Contents of one of the temperate zones, what proportion do you find them to bear to each other? If it were possible to unite the five great continents, America, Europe, Asia, Africa and Australia, what zone would they nearly fill? What two zones occupy the largest portion of the Earth’s surface? What two, the smallest?

Back to Index Next