Imagens das páginas
PDF
ePub

main outlines regulated by the mineralogy of the formations which they define, but also, in many cases, the manner in which these outlines are filled up. The colouring of the landscape is well-nigh as intimately connected with its geology as the drawing The traveller passes through a mountainous region of Gneiss.

The hills, which, though bulky, are shapeless, raise their huge backs so high over the brown dreary moors which, unvaried by precipice or ravine, stretch away for miles from their feet, that even amid the heats of midsummer the snow gleams in streaks and patches from their summits. And yet so vast is their extent of base, and their tops so truncated, that they seem but half-finished hills notwithstanding, — hills interdicted somehow in the forming, and the work stopped ere the upper storeys had been added.

pursues his journey, and enters a district of Micaceous Schist. The hills are no longer truncated, or the moors unbroken : the heavy ground-swell of the former landscape has become a tempestuous sea, agitated by powerful winds and conflicting tides. The picturesque and somewhat fantastic outline is composed of high sharp peaks, bold craggy domes, steep broken acclivities, and deeply serrated ridges ; and the higher hills seem as if set round with a framework of props and buttresses, that stretch out on every side like the roots of an ancient oak.

He passes on, and the landscape varies : the surrounding hills, though lofty, pyramidal, and abrupt, are less rugged than before ; and the ravines, though still deep and narrow, are walled by ridges no longer serrated and angular, but comparatively rectilinear and smooth. But the vegetation is even more scanty than formerly ; the steeper slopes are covered with streams of débris, on which scarce a moss or lichen finds root; and the conoidal hills, bare of soil from their summits half-way down, seem so many naked skeletons, that speak of the decay and death of nature. All is solitude and sterility. The territory is one of Quartz rock.

Still the traveller passes on ; the mountains sink into low swellings ; long rectilinear ridges run out towards the distant sea, and terminate in bluff precipitous headlands. The valleys, soft and pastoral, widen into plains, or incline in long-drawn slopes of gentlest declivity. The streams, hitherto so headlong and broken, linger beside their banks, and then widen into friths and estuaries. The deep soil is covered by a thick mantle of vegetation,-by forest trees of largest growth, and rich fields of corn ; and the solitude of the mountains has given place to a busy population. He has left behind him the primary regions, and entered on one of the secondary districts.

And these less rugged formations have also their respective styles,-marred and obliterated often by the Plutonic agency, which imparts to them in some instances its own character, and in some an intermediate one, but in general distinctly marked and easily recognised. The Chalk presents its long inland lines of apparent coast, that send out their rounded headlands, cape beyond cape, into the wooded or com-covered plains below. Here and there, there juts up at the base of the escarpment a white obelisk-like stack ; here and there, there opens into the interior a narrow grassy bay, in which noble beeches have cast anchor. There are valleys without streams; and the landscape atop is a scene of arid and uneven downs, that seem to rise and fall like the sea after a storm.

We pass on to the Oolite : the slopes are more gentle, the lines of rising ground less continuous and less coastlike; the valleys have their rivulets, and the undulating surface is covered by a richer vegetation. We enter on a district of New Red Sandstone. Deep narrow ravines intersect elevated platforms. There are lines of low precipices so perpendicular and so red, that they seem as if walled over with new brick ; and here and there, amid the speckled and mouldering sandstones that gather no covering of lichen, there stands up a huge altar-like mass of lime, mossy and grey, as if it represented a remoter antiquity than the rocks around it.

The Coal Measures present often the appearance of vast lakes frozen over during a high wind, partially broken afterwards by a sudden thaw, and then frozen again. Their shores stand up around them in the form of ridges and mountain-chains of the older rocks; and their surfaces are grooved into flat valleys and long lines of elevation. Take as an instance the scenery about Edinburgh. The Ochil hills and the Grampians form the distant shores of the seeming lake or basin on the one side, the range of the Lammermuirs and the Pentland group on the other ; the space between is ridged and furrowed in long lines, that run in nearly the same direction from north-east to south-west, as if, when the binding frost was first setting in, the wind had blown from off the northern or southern shore.

HUGH MILLER.

THE CATARACT OF VELINO.

The roar of waters !—from the headlong height
Velino cleaves the wave-worn precipice ;
The fall of waters ! rapid as the light
The flashing mass foams shaking the abyss ;
The hell of waters, where they howl and hiss,
And boil in endless torture ; while the sweat
Of their great agony, wrung from out this

Their Phlegethon, curls round the rocks of jet
That gird the gulf around, in pitiless horror set,

And mounts in spray the skies, and thence again
Returns in an unceasing shower, which round,
With its unemptied cloud of gentle rain,
Is an eternal April to the ground,

Making it all one emerald :-how profound
The gulf ! and how the giant element
From rock to rock leaps with delirious bound,

Crushing the cliffs, which, downward worn and rent
With his fierce footsteps, yield in chasms a fearful vent

To the broad column which rolls

on,

and shows
More like the fountain of an infant sea
Torn from the womb of mountains by the throes
Of a new world, than only thus to be
Parent of rivers, which flow gushingly,
With many windings, through the vale :-Look back !
Lo, where it comes like an eternity,

As if to sweep down all things in its track,
Charming the eye with dread,-a matchless cataract,

Horribly beautiful ! but on the verge,
From side to side, beneath the glittering morn,
An Iris sits, amidst the infernal surge,
Like Hope upon a death-bed ; and, unworn
Its steady dyes, while all around is torn
By the distracted waters, bears serene
Its brilliant hues with all their beams unshorn :

Resembling, 'mid the torture of the scene,
Love watching Madness with unalterable mien.

LORD BYRON.

COLOURS OF SEA WATER.

THERE are portions of the ocean in which, when we look down upon them, we can hardly see a trace of blue ; at the most, a mere hint of indigo reaches the eye.

The water, indeed, is practically black, and this is an indication both of its depth and of its freedom from mechanically suspended matter. In small thicknesses water is sensibly transparent to all kinds of light; but, as the thickness increases, the rays of low refrangibility are first absorbed, and after them the other rays. Where, therefore, the water is very deep and very pure, all the colours are absorbed, and such water ought to appear black, as no light is sent from its interior to the eye. The approximation of the Atlantic Ocean to this condition is an indication of its extreme purity.

Throw a white pebble into such water; as it sinks it becomes greener and greener, and before it disappears, it reaches a vivid blue - green. Break such a pebble into fragments, each of these will behave like the unbroken mass ; grind the pebble to powder, every particle will yield its modicum of green ; and if the particles be so fine as to remain suspended in the water, the scattered light will be a uniform green. Hence the greenness of shoal water. You go to bed with the black Atlantic around you. You rise in the morning, find it a vivid green, and correctly infer that you are crossing the Bank of Newfoundland. Such water is found charged with fine matter in a state of mechanical suspension. The light from the bottom may sometimes come into play, but it is not necessary. A storm can render the water muddy, by rendering the particles too numerous and gross. Such a case occurred towards the close of a visit I paid to Niagara. There had been rain and storm in the upper lake-regions, and the quantity of suspended matter brought down quite extinguished the fascinating green of the Horseshoe.

Nothing can be more superb than the green of the Atlantic waves, when the circumstances are favourable to the exhibition of the colour. As long as a wave remains unbroken no colour appears ; but when the foam just doubles over the crest, like an Alpine snow-cornice, under the cornice we often see a display of the most exquisite green. It is metallic in its brilliancy. But the foam is necessary to its production. The foam is first illuminated, and it scatters the light in all directions; the light which passes ough the higher portion of the wave alone reaches the eye, and gives to that portion

« AnteriorContinuar »