GEOGRAPHY. 



than with us at midsummer; and this 

 happens once on the north, and once on 

 the south side of the hemisphere. Be- 

 tween the equator and the tropics he is 

 vertical twice in the year, when his de- 

 clination is equal to. the latitude of the 

 place, and his least meridian altitudes, 

 which are unequal between themselves, 

 are at the solstices. At the tropics, the 

 meridian sun is vertical once only in the 

 year, and at the opposite solstice, or the 

 time of midwinter, his meridian altitude 

 is 43 4', as with us in April and the be- 

 ginning of September. At the polar cir- 

 cles the sun describes, on midsummer- 

 day, a complete circle, touching the north 

 or south point of the horizon ; and in mid- 

 winter he shews only half his disc above 

 it, for a few minutes, in the opposite point; 

 that is, neglecting the elevation produced 

 by refraction, which, in these climates 

 especially, is by no means inconsiderable. 

 At either pole, the corresponding pole of 

 the heavens being vertical, the sun must 

 annually describe a spiral, of which each 

 coil is nearly horizontal, half of the spiral 

 being above the horizon, and half below ; 

 the coils being much more open in the 

 middle than near the end. 



The climates, in the astronomical sense 

 of the word, are determined by the dura- 

 tion of the longest day in different parts 

 of the earth's surface; but this division is 

 of no practical utility, nor does it furnish 

 any criterion for judging of the climate 

 in a meteorological sense. 



The natural division of the surface of 

 the globe is into sea and land ; about 

 three-fourths of the whole being occupied 

 by water, although probably no where to 

 a depth comparatively very considerable, 

 at most of a few miles on an average. 

 The remaining fourth consists of lands, 

 elevated more or less above the level of 

 the sea, interspersed, in some parts, with 

 smaller collections of water, at various 

 heights, and in a few instances, some- 

 what lower than the general surface of 

 the main ocean. Thus the Caspian Sea 

 is said to be about three hundred feet 

 lower than the ocean; and in the interior 

 parts of Africa there is probably a lake 

 equally depressed. 



We cannot observe any general sym- 

 metry in this distribution of the earth's 

 surface ; excepting that the two large 

 continents of Africa and South America 

 have some slight resemblance in their 

 forms, and that each of them is terminat- 

 ed to the eastward by a collection of 

 numerous islands. The large capes pro- 

 jecting to the southward have also a 



similarity with respect io their form, and 

 the islands near them ; to the west the 

 continents are excavated into large bays, 

 and the islands are to the east : thus Cape 

 Horn has the Falkland Islands ; the Cape 

 of Good Hope, Madagascar ; and Cape 

 Comorin, Ceylon, to the east. 



The great continent, composed of Eu- 

 rope, Asia, and Africa, constitutes about 

 a seventh of the whole surface of the 

 earth : America about a sixteenth ; and 

 Australasia, or New South Wales, about 

 a fiftieth ; or in hundreth parts of the 

 whole, Europe contains two ; Asia, seven; 

 Africa, six; America, six; and Austra- 

 lasia, two : the remaining seventy -seven 

 being sea ; although some authors assign 

 seventy-two parts only out of one hun- 

 dred to the sea, and twenty-eight to the 

 land. 



These proportions may be ascertained 

 with tolerable accuracy by weighing the 

 paper made for covering a globe, first 

 entire, and then cut out according to the 

 terminations of the different countries ; 

 or, if still greater precision were requir- 

 ed, the greater part of the continents 

 might be divided into known portions 

 of the whole spherical surfac e, and the 

 remaining irregular portions only weigh- 

 ed. 



The general inclinations and levels of 

 the continents are discovered by the 

 courses of their rivers. Of these the prin- 

 cipal are, the river of Amazons, the Sene- 

 gal, the Nile, the river St. Lawrence, 

 the Hoangho, the river La Plata, the 

 Jenisei, the Mississippi, the Volga, the 

 Oby, the Amur, the Oronooka, the Gan- 

 ges, the Euphrates, the Danube, the Don, 

 the Indus, the Dnieper, and the Dwina ; 

 and this is said to be nearly the order of 

 their magnitudes. But if we class them 

 according to the length of country through 

 which they run, the order will, according 

 to Major Kennel's calculation, be some- 

 what different ; taking the length of the 

 Thames for unity, he estimates that of 

 the River Amazons at 15f ; the Kian 

 Kew,in China, 15 ; the Hoangho, 13 ; 

 the Nile, 12 ; the Lena, 1H ; the Amur, 

 11 ; the Oby, 10 ; the Jenisei, 10 ; the 

 Ganges, its companion the Burampooter, 

 the river of Ava, and the Volga, each 9| ; 

 the Euphrates, 8 ; the Mississippi, 8 ; the 

 Danube 7 ; the Indus, 5^ ; and the 

 Rhine, 5. 



We may form a tolerable accurate idea 

 of the levels of the ancient continent, by 

 tracing a line across it in such a direction 

 as to pass no river, which will obviously 

 indicate a tract of country higher thau 



