or southward, the POLAR STAR appeared to ascend or descend in proportion to the space passed over; and that while all the stars in the direction in which they travelled appeared to recede from the horizon, those in the opposite direction continually approached it. They found moreover, that as they sailed southward, new stars appeared above the southern point of the horizon, and, if they passed the equator, others, with which they had long been familiar, sank out of view in the north. They, therefore, concluded that the surface of the earth from north to south also was globular; and as similar appearances were observed in every direction, they finally came to the conclusion that the earth was an immense SPHERE or globe.

In eclipses of the moon, the shadow of the earth is always circular, which is another proof of its sphericity. The shadow cast by a round body, like a plate on the wall of a lighted room, is circular only when the back or front of it is turned towards the wall; but a ball or globe, no matter how it may be turned, always casts a circular shadow.

As a vessel recedes from the land, the spectators on shore lose sight first of the hull, next of the lower sails, and finally only the tops of the masts are perceptible. This is evidently not the effect of distance; for, if so, the masts, which are smaller than the hull or body of the ship, would first disappear. It is occasioned by the convex or globular surface of the sea, which rises up between the ship and the spectators. This they may easily prove, for if they immediately ascend a tower or eminence, the vessel will again be visible. Similar appearances present themselves to the persons on board the vessel; first the shore begins to sink, next the buildings, next the tops of spires and mountains only are perceptible, and finally they lose sight of land. It is under these circumstances that

"The sailor sighs as sinks his native shore,

And climbs the mast to feast his eyes once more."

Similar appearances are observed in every part of the earth, and in every direction. Towers and mountains, as we recede from them, seem to sink below the horizon, their bases disappearing first, next their middle parts, and finally their summits. And in every sea in the world, and in every direction, the most extended view is had from the mast-head

of the vessel; and hence sailors always go aloft when they are on the look-out for land, or for any other object which they may wish to seek or shun.

It may now be added, that the earth could be nothing else than a sphere, in accordance with its motions as a PLANET, of which we shall presently speak; and even the cause of its sphericity may be shown.

We know that every particle of matter attracts and is mutually attracted by every other particle of matter which comes within the sphere of its influence; and consequently, that the greater the quantity of matter, the greater will be the attractive power. Hence the several kinds of attraction, which are, possibly, all modifications of the same principle :1. COHESION, or the mutual attraction of minute particles of matter of the same kind in contact with each other. 2. GRAVITATION, or that power which causes bodies to attract each other in proportion to the quantity of matter which they contain, and inversely as the square of their distance. 3. MAGNETISM, or that property in the magnet or loadstone which attracts iron. 4. ELECTRICITY," which is exemplified by the attraction of feathers, or light substances suspended near the electrical conductor.

It is the attraction of cohesion which causes the particles of matter of which bodies are composed to cohere or stick together. Without it, all the bodies in the universe would fall into pieces, or rather crumble into indivisible particles or ATOMS. It was this property, originally impressed upon matter by the hand of the Creator, which caused the earth, the planets, and all the heavenly bodies to assume, and still enables them to retain their globular forms. One of our poets has beautifully and truly said-

"That very law which moulds a tear,

And bids it trickle from its source-
That law preserves the earth a sphere,

And guides the planets in their course;"

for the same principle is exemplified in the dew-DROPS which hang from the thorn, and in the rain-DROPS which fall from the clouds. The minute vapoury particles of which DEW

Electricity.-From electron, the Greek word for amber, in which this property was first observed. The term electron was applied to other shining substances, as to a mixture, four parts gold, and one part silver. The root is helios, the sun, as in perihelion.

and RAIN are composed, by coming into contact, mutually attract each other, and form into DROPS or small globes.

The numerous globules into which a small quantity of quicksilver forms, when it falls upon a table or the floor, exemplify the same principle. The particles which come into contact attract, and are attracted by each other, mutually, on all sides, and hence the globular form is assumed. And, as from the nature or form of a globe there is more matter in the direction of its centre than in any other, the general attraction of all the constituent particles or parts will be towards the centre.

Apply this to the original formation of the great globe which we inhabit. "In the beginning" it was "without form and void;" but when destined for the abode of man, its elements were reduced to order by the Creative Word; and from a chaotic and confused state, it assumed, in consequence of the mutual and general attraction of all its constituent particles, the form of a GLOBE. And here it may be observed, that this was the only form which the earth could assume consistent with its position in pure space, and the rotatory motion which, for the benefit of mankind, it was destined to perform. For, suppose a round body like the earth were placed in pure space, remote from the attractive influence of any other body, it is easy to conceive that it would, self-balanced and self-supported, remain in the same position for ever. It would neither move down, nor up, nor backwards, nor forwards, nor in any direction whatever; for we have supposed that there are no other bodies to attract or draw it towards them. In fact, such a body, in such a position, would be without weight or gravity; for all its parts, on every side, would be attracted towards its centre or middle point, and an EQUILIBRIUM would be produced.

The CENTRE OF GRAVITY of a body is that point on which the whole weight is, as it were, concentrated or balanced; and if the body be a globe of uniform density, it is evident from what has been said, that the centre of gravity will coincide

• The same principle is exemplified in the manufacture of shot. "If the small shot which is used by sportsmen were cast in a mould, the price would be enormous; but by pouring the melted lead of which the shot is made, through a cullender placed at the top of a tower high enough for the lead to cool in its passage through the air before it reaches the ground, the shot is formed in a spherical or round shape, by the mere act of passing through the atmosphere."-Results of Machinery.

with the centre or middle point of the globe. In this way, all the parts of the earth, on every side, are attracted towards its centre or middle point; and so is every thing, and every person on its surface; and there is not the least danger of our falling from it, though our feet are often up, and our heads down, like flies on the ceiling. But the fact is, our feet are always down and our heads up; for these terms properly refer to the centre and surface of the earth. The middle point of a globe is the lowest, and down consequently means in the direction of the centre; and up means from the centre towards the surface; and it is in this way we use these terms with regard to the earth. But with regard to the heavens, the direction expressed by these terms is constantly changing. What we call up, during the day, we call down, during the night. Our ANTIPODES, therefore-that is, the inhabitants of the earth who live on the opposite side of it, and consequently have their feet opposite to ours-are in no more danger of falling off than we are ourselves. They have, like all the inhabitants of the globe, the earth beneath their feet, and the heavens above their heads.

QUESTIONS FOR EXAMINATION ON CHAP. I.

Pages 15, 16.-The meaning of the term Geography? 2. How may Geography be divided? 3. What is Mathematical Geography? 4. With what other sciences is this branch of Geography connected? 5. What is Physical Geography? 6. With what other sciences is this branch of Geography connected? 7. What is Political Geography? 8. With what other sciences is this branch of Geography connected?

Pages 16, 18.-The form of the earth? 2. What is a sphere? 3. An oblate spheroid? 4. Aprolate? 5. How would you illustrate the form of the earth? 6. How the axis and diurnal motion? 7. If the earth is a globe, why does not its surface appear globular? 8. How illustrate this ? 9. If a person six feet high stood in the middle of an extensive plain, how far could he see the surface of the earth around him? 10. Why are mountains and inequalities upon the earth's surface no argument against its sphericity? 11. What would be the size of the highest mountain in the world, if represented in relative proportions upon the surface of an artificial globe 12 inches in diameter? 12. How do you show this? 13. The practical proof of the sphericity of the earth? 14. How illustrate what is meant by sailing round the world?

a Antipodes. From the Greek word ANTI, opposite, and PÕDES, the feet. Places that are the antipodes of each other are equally distan from the equator, but in different hemispheres; and as they are on opposite sides of the globe, their meridians are as far as they can be apart, that is 180°.

b A careful perusal of the text will enable the pupils to give satisfactory answers to these questions. See the Preface.

Pages 18, 19.-The first person who attempted to circumnavigate the earth? 2. The first who succeeded? 3. Can you state the arguments which led Columbus, and others long before his time, to conclude that the earth must be a sphere? 4. Is sailing round the world from west to east, or vice versa, a proof of its sphericity 5. How is it shown that the earth's surface is globular from north to south also? 6. The proof from the eclipses of the moon? 7. Can you state other and more familiar proofs of the earth's sphericity in every direction? 8. Why should the hull or body of a ship continue longer in sight than the masts? 9. Why do sailors go aloft when they are on the look-out for land, or for any distant object? 10. How show that the form of the earth must be spherical

Pages 20, 22.-The nature of attraction? 2. The different kinds or modifications of attraction? 3. Without the attraction of cohesion, what would take place? 4. Can you repeat the lines in illustration of the preceding question ? 5. How is the same principle exemplified in the rain and dewdrops? 6. Also in the globules of quicksilver? 7. And in the manufacture of small shot? 8. Why in a globe or spherical body is the attraction of all the parts in the direction of the centre? 9. How apply this to the original formation of the earth? 10. Under what circumstances would the earth, or any round body like it, remain self-balanced in pure space? 11. What is meant by the centre of gravity of a body? 12. Do the centre of gravity and the centre or middle point in a globe or spherical body coincide? 13. The lowest part or point in a globe? 14. The meaning of the terms up and down, as applied to the earth? 15. As applied to the heavens? 16. The meaning of the term antipodes? 17. In what direction is every part of the earth, and every thing and every person on its surface attracted? 18. Why in the direction of the centre?

CHAPTER II.

MOTIONS OF THE EARTH.

If you hold a small globe or ball before a candle, you will observe that the one-half of it will be illuminated and the other half shaded; and if you make the ball spin or turn round you will see that half of it will be in the light, and half in the shade, in succession.

Now this is an exact representation of the DIURNAL or daily motion of the earth. The earth is a globe, and as it turns round and round before the sun, the one-half of it is enlightened by his rays, and the other half deprived of his light, in succession. With the half turned towards the sun, it is day, and with the half turned from the sun, it is night. And as the earth is twenty-four hours" in turning once

a Accurately, 23 hours, 56 minutes, and 4 seconds.