« ПретходнаНастави »
hills, icebergs, plains, and seas, are all travelling eastward only about as fast as an express railway train.
SUN-SHINE AND SUN-SHADOW AT THE EQUATOR.
At the Equator the sun is seldom far from overhead. several months, indeed, the eye can scarcely detect whether he is overhead or not, and for the remainder of the year he approaches so near that position that the inhabitants of equatorial countries are said to live under a vertical sun. It is different in Britain. At mid-summer we can easily see that the noonday sun, though high in the heavens, is far from being right overhead. At midwinter he is so low that he shines right in our faces, and can sometimes barely hold his own against mists and fogs, which blot him out from the sky altogether, or allow only a round of dull red light to intimate to men where he is. But though the Equator has the sun almost overhead for nearly the whole year, it seldom gets a glimpse of the Pole Star. At times, travellers from the far north have caught sight of their familiar friend, shining, not overhead, but, as it were, along the ground, at the further end, it may be, of some long valley, in which no mists gather to obscure the heavens.
In Britain the sun is always in the south quarter of the heavens at mid-day. He rises in the east, passes round to the south, and moving further round, at last sets in the west. We never see him in the north. The noonday shadows which he throws behind men, trees, hills, and all things, will therefore lie towards the north. But those that dwell on the Equator are more favoured. On the 22d of March, and for some time before and after, they see that he is neither north nor south at noon. He then rises due east in the morning; he sets due west in the evening. After six hours' climbing of the eastern sky, he gains the highest point, looks right down on the earth girdle of mountain, and then for six hours more slides down in the west. When he rises at six o'clock in the morning, the shadows of men, and trees, and spires, and hills are thrown away due west in long dark lines. As he climbs upward, the shadows shorten, until at mid-day, when he is overhead, they are entirely gone. For an instant the world along
that part of the ridge of the Equator is shadowless. But soon the shadows re-appear on the east or opposite side to where they were in the forenoon, but so foreshortened as to be grotesque. As the sun sinks lower, they lengthen out, till at his setting they stretch eastward in lines as long as stretched westward in the morning.
Between the end of March and the end of June the sun moves slowly towards the north quarter of the heavens. He ceases to rise exactly in the east, to set exactly in the west, and to look down on the Equator exactly from overhead at noon. The mid-day shadows of things creep out from being nothing about the end of March to three-fifths of their natural size about the end of June. A palm tree 100 feet in height casts no shadow at mid-day in March, and one nearly 44 feet long in June. A man, though shadowless in spring, will be followed in summer by a dwarf image of himself at least two feet in length. In Britain the shadows are much longer at noon. Near the centre of it (say in latitude 56°) a tree 100 feet in height casts a mid-day shadow of about 64 feet at mid-summer, and one of 540 feet at mid-winter. At mid-summer, a man of average height casts a shadow of 3 or 4 feet, and at mid-winter of 30 feet.
From June to September the mid-day shadows at the Equator gradually shorten, for the sun in returning from the north is getting nearer and nearer overhead. By the end of September everything is in the broad glare of a vertical sun, from whose beams there is no escape out of doors. No shady side of the street, no friendly cliff, or hill, or mountain, no far-stretching ground picture of tree, or bush, or hedge, offers wearied men and panting beasts a hiding place from the heat and glare. Nothing but a screen overhead, such as the roof of a house or the thick foliage of great trees, can ward off the sun's beams. No wonder, then, that in countries where mid-day is altogether or almost shadowless, business is stopped for a time, men enjoy their siesta or noontide slumbers, and all nature yields to the heat, till a sinking sun and shadows lengthening eastward again rouse the world to life and action. From September to December the sun moves away from overhead at the Equator to the southern quarter
of the heavens. Mid-day shadows creep out, as it were, from hiding, slowly stealing northward as he goes south. By the end of the year they attain their greatest length on the north, precisely as, six months before, they were at their greatest on the south.
The changes of position gone through by noontide sun and noontide shadow during the year at the Equator may now be thus summed up: In the beginning of January the sun is somewhat to the south of the Equator, and shadows of things, three-fifths of the natural size, stretch northward along the ground. In the end of March the sun is overhead at noon, and the world is then shadowless. By the beginning of July he is as far north as he was south in January; and, on the other hand, the shadows of all things stretch as far to the south as they then did to the north. In September he is again overhead, and nature is again shadowless at noon.
SINKING OF THE NORTH POLE STAR.
A STAR has left the kindling sky
A lovely northern light;
How many planets are on high,
I miss its bright familiar face;
It rose upon our English sky,
Shone o'er our English land,
It seemed to answer to my thought;
And with its welcome presence brought
The voyage it lights no longer, ends
Fresh from the pain it was to part
How could I bear the pain?
Yet strong the omen in my heart
Meet with a deeper, dearer love:
That none looked up with me.
I seem to stand beside a grave,
Farewell! ah, would to me were given
Kind messages of love and hope
Upon thy rays should be:
Oh, fancy vain, as it is fond,
And little needed too!
My friends-I need not look beyond
L. E. LANDON.
THIS giant among the rivers of the earth takes its rise among the glaciers of the Cordilleras. The first European who sailed down its mighty waters (in 1541) was Orellana, a Portuguese. He reported that he had met with a nation of female warriors on its banks; and hence, though this was a fable, arose the name Amazona.
After emerging from the Andes, swelled by tributary streams, it winds through the vast savannahs of South America, till it has run a course of nearly four thousand miles. Before reaching the Atlantic, the vast flood is fifty miles wide, and in mid-channel the opposite coasts are not visible. It seems more like a fresh-water sea than a river. At its mouth a vehement struggle takes place between the river flowing down and the tide running up. Twice every day they dispute the preeminence; and in the meeting of the enormous masses of water a ridge of surf and foam is raised to a height of one hundred and eighty feet.
At a distance of five hundred miles out at sea the waters of the Amazon are still perceptible. For the last four hundred and fifty miles of its course it is never less than four miles wide, while the depth is so great that large vessels may go up the channel for two thousand miles and still be in forty fathoms of water. Flowing, however, through a region very scantily peopled, there are fewer vessels upon its surface throughout the year than are seen every hour of the day on the bosom of the Mississippi.
The researches of travellers, from the days of Pinzon and Orellana to those of Humboldt and the present time, have shown that the vegetable and animal productions of the basin of the Amazon outnumber in species and varieties nearly all the products of the same kingdoms in Europe and North America taken together; and yet many tributaries of this mighty stream, flow
ing from the vast unknown interior to the north and south, have been only partially explored. What a noble field for enterprise, when even the fibres and nuts of a few species of palm afford valuable objects of trade!
It is remarkable, that while Brazil abounds with rivers, on the other side of the continent rain never falls, and the country is dry and comparatively barren. "I have seen," says a traveller, "the western and eastern coasts of South America within thirty days of each other, and the former seemed a desert compared with the latter."
The reason of this is thus stated by Lieutenant Maury :"The south-east trade-winds in the Atlantic Ocean first strike the water on the coast of Africa. Travelling to the north-west, they blow obliquely across the ocean until they reach the coast of Brazil. By this time they are heavily laden with vapour, which they continue to bear along across the continent, depositing it as they go, and supplying with it the sources of the Rio de la Plata, and the southern tributaries of the Amazon. Finally, they reach the snow-capped Andes, and here is wrung from them the last particle of moisture that that very low temperature can extract. Reaching the summit of that range, they now tumble down as cool and dry winds on the Pacific slopes beyond. Meeting with no evaporating surface, and with no temperature colder than that to which they were subjected on the mountain-tops, they reach the ocean before they become charged with fresh vapour, and before, therefore, they have any which the Peruvian climate can extract. Thus we see how the top of the Andes becomes the reservoir from which are supplied the rivers of Chili and Peru."