תמונות בעמוד
PDF
ePub
[merged small][ocr errors][ocr errors][ocr errors][merged small][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors]
[graphic]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]

YOL THE

MODERN PRECEPTOR.

CHAPTER VI.

ON GEOGRAPHY.

[ocr errors]

BY GEOGRAPHY is meant thåt pårt of science which teaches the form of this earth which we inhabit, as also its several divisions into quarters, empires, kingdoms, and other states, with their respective boundaries and subdivisions, and the relative positions of countries, cities, towns, moun. tains, seas, lakes, rivers, and other remarkable objects on the earth's surface.

The term geography is formed from two Greek words, signifying, in general, a description of the earth, although the science has been divided into two branches, ģeography, properly so called, or a description of the land, and hydrography, or a description of the water of sea.

On the utility or importante of the study of geography it would be idle to expatiate : every person's experience must show that some acquaintance with it is indispensible in the ordinary intercourse and business of society; and hence we find, that to geography the attention of mankind was attracted from the earliest periods of history; at least, VOL. II.

B

so

so far as regarded descriptions of the various positions of the earth. The art, however, of representing such portions of the earth, on a plane surface, cannot well be traced back beyond the days of the Greek philosopher Thales, and his successor Anaximander, who, about the year 580 before the Christian era, produced a geographical table, perhaps a map, exhibiting the situation of Greece and the neighbouring countries.

After Anaximander came a succession of geographers, of whose writings, in general, only imperfect fragments have come down to our times : but, at last, in the reign of Augustus Cæsar, about the year 19 of Christ, appeared Strabo, a native of Amasia, in Lesser Asia, who composed a general system of geography, which has, happily, been preserved to our day, and which, besides topographical and historical informations concerning all such parts of the earth as were then known, many of which he had visited, contains Sundry curious discussions on disputed points of geography, together with numerous extracts from the writings of prior travellers and geographers, which, but for Strabo's work, would have been utterly lost to the world,

Still, however,, was wanting a treatise which, to the informations contained in the writings of Strabo and his predecessors, should add the philosophical and geometrical principles on which geography rests, as forming a part of the science of the universe. Such a treatise was produced, about a century and a balf after Strabo, by Ptolemy the Alexandrian, containing instructions for the due construction of maps, for the representation of a sphere on a plane surface, and for determining the positions of countries, towns, &c. agrecably to their proper and relative situations on the surface of the carth, as ascertained by what is termed their. latitude and longitude.

Of inodern geographers it may be sufficient to mention the names of De Lisle and D'Anville in France, particularly

tbc

the latter, who, for the learning and the sagacity displaved, in his numerous dissertations on many portions of ancient and modern geography, as well as for his maps, deservedly enjoys the highest reputation : amongst ourselves, the labours of Rennell and Vincent are entitled to the greatest attention from every lover of genuine geographical dis. cussion.

The uninformed and inconsiderate part of mankind, in modern, as well as in ancient times, have been of opinion, that this earth is a vast extended plane, bounded on all sides by the sea and the heavens : more attentive observers were, however, long ago persuaded that the earth is a round ball, globe, or sphere, maintaining its appointed place amongst the innumerable bodies composing the universe, and far removed from contact with any other body of either the same: or a different kind.

How the ancients came to be convinced of the splıericali form of the earth, we have now no means of discovering : but, by attending to the following facts, we may easily be.. led to adopt the same opinion. When we stand on the margin of a lake or arm of the sea of considerable breadih, and carefully observe such objects on the opposite side as seem 10 touch the surface of the water ; if we stoop the eye slowly down to the ground, we will gradually lose sight of the objects we had at first remarked : on the contrary, if instead of lowering the eye we shall raise it, by ascending an. eminence, climbing up a ship's mast, or the like, we will, as we ascend gradually, discover new objecis lower than those at first noticed along the surface of the water, and their number will be increased in proportion to the height to which the eye is elevated.

These effects can be produced by no other cause than the rounded swelling surface of the water between the objects and the eye, which surface, if we take only a small portion of it, may, it is true, be considered as being perfectly level B 2

and

[ocr errors]
« הקודםהמשך »