FOOTNOTES:

Steadfast, serene, immovable, the sameYear after year.

Directly we see the coast, or even a ship, the case is altered. Boats may remain the same for centuries, but ships are continually being changed. The wooden walls of old England are things of the past, and the ironclads of to-day will soon be themselves improved off the face of the ocean.

The great characteristic of Lakes is peace, that of the Sea is energy, somewhat restless, perhaps, but still movement without fatigue.

The Earth lies quiet like a child asleep,The deep heart of the Heaven is calm and still,Must thou alone a restless vigil keep,And with thy sobbing all the silence fill.[59]

A Lake in a storm rather gives us the impression of a beautiful Water Spirit tormented by some Evil Demon; but a storm at Sea is one of the grandest manifestations of Nature.

Yet more; the billows and the depths have more;High hearts and brave are gathered to thy breast;They hear not now the booming waters roar,The battle thunders will not break their rest.Keep thy red gold and gems, thou stormy grave;Give back the true and brave.[60]

The most vivid description of a storm at sea is, I think, the following passage from Ruskin'sModern Painters:

"Few people, comparatively, have ever seen the effect on the sea of a powerful gale continued without intermission for three or four days and nights; and to those who have not, I believe it must be unimaginable, not from the mere force or size of the surge, but from the complete annihilation of the limit between sea and air. The water from its prolonged agitation is beaten, not into mere creaming foam, but into masses of accumulated yeast, which hangs in ropes and wreaths from wave to wave, and, where one curls over to break, form a festoon like a drapery from its edge; these are taken up by the wind, not in dissipating dust, but bodily, in writhing, hanging, coiling masses, which make the airwhite and thick as with snow, only the flakes are a foot or two long each: the surges themselves are full of foam in their very bodies underneath, making them white all through, as the water is under a great cataract; and their masses, being thus half water and half air, are torn to pieces by the wind whenever they rise, and carried away in roaring smoke, which chokes and strangles like actual water. Add to this, that when the air has been exhausted of its moisture by long rain, the spray of the sea is caught by it as described above, and covers its surface not merely with the smoke of finely divided water, but with boiling mist; imagine also the low rain-clouds brought down to the very level of the sea, as I have often seen them, whirling and flying in rags and fragments from wave to wave; and finally, conceive the surges themselves in their utmost pitch of power, velocity, vastness, and madness, lifting themselves in precipices and peaks, furrowed with their whirl of ascent, through all this chaos, and you will understand that there is indeed no distinction left between the sea and air; that no object, norhorizon, nor any landmark or natural evidence of position is left; and the heaven is all spray, and the ocean all cloud, and that you can see no further in any direction than you see through a cataract."

The Sea teems with life. The Great Sea Serpent is, indeed, as much a myth as the Kraken of Pontoppidan, but other monsters, scarcely less marvellous, are actual realities. The Giant Cuttle Fish of Newfoundland, though the body is comparatively small, may measure 60 feet from the tip of one arm to that of another. The Whalebone Whale reaches a length of over 70 feet, but is timid and inoffensive. The Cachalot or Sperm Whale, which almost alone among animals roams over the whole ocean, is as large, and much more formidable. It is armed with powerful teeth, and is said to feed mainly on Cuttle Fish, but sometimes on true fishes, or even Seals. When wounded it often attacks boats, and its companions do not hesitate tocome to the rescue. In one case, indeed, an American ship was actually attacked, stove in, and sunk by a gigantic male Cachalot.

The Great Roqual is still more formidable, and has been said to attain a length of 120 feet, but this is probably an exaggeration. So far as we know, the largest species of all is Simmond's Whale, which reaches a maximum of 85 to 90 feet.

In former times Whales were frequent on our coasts, so that, as Bishop Pontoppidan said, the sea sometimes appeared as if covered with smoking chimneys, but they have been gradually driven further and further north, and are still becoming rarer. As they retreated man followed, and to them we owe much of our progress in geography. Is it not, however, worth considering whether they might not also be allowed a "truce of God," whether some part of the ocean might not be allotted to them where they might be allowed to breed in peace? As a mere mercantile arrangement the maritime nations would probably find this very remunerative. The reckless slaughter of Whales, Sea Elephants, Seals,and other marine animals is a sad blot, not only on the character, but on the common sense, of man.

The monsters of the ocean require large quantities of food, but they are supplied abundantly. Scoresby mentions cases in which the sea was for miles tinged of an olive green by a species of Medusa. He calculates that in a cubic mile there must have been 23,888,000,000,000,000, and though no doubt the living mass did not reach to any great depth, still, as he sailed through water thus discoloured for many miles, the number must have been almost incalculable.

This is, moreover, no rare or exceptional case. Navigators often sail for leagues through shoals of creatures, which alter the whole colour of the sea, and actually change it, as Reclus says, into "une masse animée."

Still, though the whole ocean teems with life, both animals and plants are most abundant near the coast. Air-breathing animals, whether mammals or insects, are naturally not well adapted to live far from dry land. Even Seals, though some of them make remarkablemigrations, remain habitually near the shore. Whales alone are specially modified so as to make the wide ocean their home. Of birds the greatest wanderer is the Albatross, which has such powers of flight that it is said even to sleep on the wing.

Many Pelagic animals—Jelly-fishes, Molluscs, Cuttle-fishes, Worms, Crustacea, and some true fishes—are remarkable for having become perfectly transparent; their shells, muscles, and even their blood have lost all colour, or even undergone the further modification of having become blue, often with beautiful opalescent reflections. This obviously renders them less visible, and less liable to danger.

The sea-shore, wherever a firm hold can be obtained, is covered with Sea-weeds, which fall roughly into two main divisions, olive-green and red, the latter colour having a special relation to light. These Sea-weeds afford food and shelter to innumerable animals.

The clear rocky pools left by the retiring tide are richly clothed with green sea-weeds, while against the sides are tufts of beautifulfilmy red algæ, interspersed with Sea-anemones,—white, creamy, pink, yellow, purple, with a coronet of blue beads, and of many mixed colours; Sponges, Corallines, Starfish, Limpets, Barnacles, and other shell-fish; feathery Zoophytes and Annelides expand their pink or white disks, while here and there a Crab scuttles across; little Fish or Shrimps timidly come out from crevices in the rocks, or from among the fronds of the sea-weeds, or hastily dart from shelter to shelter; each little pool is, in fact, a miniature ocean in itself, and the longer one looks the more and more one will see.

The dark green and brown sea-weeds do not live beyond a few—say about 15—fathoms in depth. Below them occur delicate scarlet species, with Corallines and a different set of shells, Sea-urchins, etc. Down to about 100 fathoms the animals and plants are still numerous and varied. But they gradually diminish in numbers, and are replaced by new forms.

To appreciate fully the extreme loveliness of marine animals they must be seen alive."A tuft of Sertularia, laden with white, or brilliantly tinted Polypites," says Hincks, "like blossoms on some tropical tree, is a perfect marvel of beauty. The unfolding of a mass of Plumularia, taken from amongst the miscellaneous contents of the dredge, and thrown into a bottle of clear sea-water, is a sight which, once seen, no dredger will forget. A tree of Campanularia, when each one of its thousand transparent calycles—itself a study of form—is crowned by a circlet of beaded arms, drooping over its margin like the petals of a flower, offers a rare combination of the elements of beauty.

"The rocky wall of some deep tidal pool, thickly studded with the long and slender stems of Tubularia, surmounted by the bright rose-coloured heads, is like the gay parterre of a garden. Equally beautiful is the dense growth of Campanularia, covering (as I have seen it in Plymouth Sound) large tracts of the rock, its delicate shoots swaying to and fro with each movement of the water, like trees in a storm, or the colony of Obelia on the waving frond of the tangle looking almostethereal in its grace, transparency, and delicacy, as seen against the coarse dark surface that supports it."

Few things are more beautiful than to look down from a boat into transparent water. At the bottom wave graceful sea-weeds, brown, green, or rose-coloured, and of most varied forms; on them and on the sands or rocks rest starfishes, mollusca, crustaceans, Sea-anemones, and innumerable other animals of strange forms and varied colours; in the clear water float or dart about endless creatures; true fishes, many of them brilliantly coloured; Cuttle-fishes like bad dreams; Lobsters and Crabs with graceful, transparent Shrimps; Worms swimming about like living ribbons, some with thousands of coloured eyes, and Medusæ like living glass of the richest and softest hues, or glittering in the sunshine with all the colours of the rainbow.

And on calm, cool nights how often have I stood on the deck of a ship watching with wonder and awe the stars overhead, and the sea-fire below, especially in the foaming, silvery wake of the vessel, where often suddenlyappear globes of soft and lambent light, given out perhaps from the surface of some large Medusa.

"A beautiful white cloud of foam," says Coleridge, "at momently intervals coursed by the side of the vessel with a roar, and little stars of flame danced and sparkled and went out in it; and every now and then light detachments of this white cloud-like foam darted off from the vessel's side, each with its own small constellation, over the sea, and scoured out of sight like a Tartar troop over a wilderness."

Fish also are sometimes luminous. The Sun-fish has been seen to glow like a white-hot cannon-ball, and in one species of Shark (Squalus fulgens) the whole surface sometimes gives out a greenish lurid light which makes it a most ghastly object, like some great ravenous spectre.

The Land bears a rich harvest of life, but only at the surface. The Ocean, on the contrary,though more richly peopled in its upper layers, which swarm with such innumerable multitudes of living creatures that they are, so to say, almost themselves alive—teems throughout with living beings.

The deepest abysses have a fauna of their own, which makes up for the comparative scantiness of its numbers, by the peculiarity and interest of their forms and organisation. The middle waters are the home of various Fishes, Medusæ, and animalcules, while the upper layers swarm with an inexhaustible variety of living creatures.

It used to be supposed that the depths of the Ocean were destitute of animal life, but recent researches, and especially those made during our great national expedition in the "Challenger," have shown that this is not the case, but that the Ocean depths have a wonderful and peculiar life of their own. Fish have been dredged up even from a depth of 2750 fathoms.

The conditions of life in the Ocean depths are very peculiar. The light of the sun cannot penetrate beyond about two hundredfathoms; deeper than this complete darkness prevails. Hence in many species the eyes have more or less completely disappeared.

Sir Wyville Thomson mentions a kind of Crab (Ethusa granulata), which when living near the surface has well developed eyes; in deeper water, 100 to 400 fathoms, eyestalks are present, but the animal is apparently blind, the eyes themselves being absent; while in specimens from a depth of 500-700 fathoms the eyestalks themselves have lost their special character, and have become fixed, their terminations being combined into a strong, pointed beak.

In other deep sea creatures, on the contrary, the eyes gradually become more and more developed, so that while in some species the eyes gradually dwindle, in others they become unusually large.

Many of the latter species may be said to be a light to themselves, being provided with a larger or smaller number of curious luminous organs. The deep sea fish are either silvery, pink, or in many cases black, sometimes relieved with scarlet, and when the luminousorgans flash out must present a very remarkable appearance.

We have still much to learn as to the structure and functions of these organs, but there are cases in which their use can be surmised with some probability. The light is evidently under the will of the fish.[61]It is easy to imagine a Photichthys (Light Fish) swimming in the black depths of the Ocean, suddenly flashing out light from its luminous organs, and thus bringing into view any prey which may be near; while, if danger is disclosed, the light is again at once extinguished. It may be observed that the largest of these organs is in this species situated just under the eye, so that the fish is actually provided with a bull's eye lantern. In other cases the light may rather serve as a defence, some having, as, for instance, in the genus Scopelus, a pair of large ones in the tail, so that "a strong ray of light shot forth from the stern-chaser may dazzle and frighten an enemy."

In other cases they appear to serve aslures. The "Sea-devil" or "Angler" of our coasts has on its head three long, very flexible, reddish filaments, while all round its head are fringed appendages, closely resembling fronds of sea-weed. The fish conceals itself at the bottom, in the sand or among sea-weed, and dangles the long filaments in front of its mouth. Little fishes, taking these filaments for worms, unsuspectingly approach, and thus fall victims.

Several species of the same family live at great depths, and have very similar habits. A mere red filament would be invisible in the dark and therefore useless. They have, however, developed a luminous organ, a living "glow-lamp," at the end of the filament, which doubtless proves a very effective lure.

In the great depths, however, fish are comparatively rare. Nor are Molluscs much more abundant. Sea-urchins, Sea Slugs, and Starfish are more numerous, and on one occasion 20,000 specimens of an Echinus were brought up at a single haul. True corals are rare, nor are Hydrozoa frequent, though a giant species, allied to the little Hydra of our ponds butupwards of 6 feet in height, has more than once been met with. Sponges are numerous, and often very beautiful. The now well known Euplectella, "Venus's Flower-basket," resembles an exquisitely delicate fabric woven in spun silk; it is in the form of a gracefully curved tube, expanding slightly upwards and ending in an elegant frill. The wall is formed of parallel bands of glassy siliceous fibres, crossed by others at right angles, so as to form a square meshed net. These sponges are anchored on the fine ooze by wisps of glassy filaments, which often attain a considerable length. Many of these beautiful organisms, moreover, glow when alive with a soft diffused light, flickering and sparkling at every touch. What would one not give to be able to wander a while in these wonderful regions!

It is curious that no plants, so far as we know, grow in the depths of the Ocean, or, indeed, as far as our present information goes, at a greater depth than about 100 fathoms.

As regards the nature of the bottom itself, it is in the neighbourhood of land mainlycomposed of materials, brought down by rivers or washed from the shore, coarser near the coast, and tending to become finer and finer as the distance increases and the water deepens. The bed of the Atlantic from 400 to 2000 fathoms is covered with an ooze, or very fine chalky deposit, consisting to a great extent of minute and more or less broken shells, especially those of Globigerina. At still greater depths the carbonate of lime gradually disappears, and the bottom consists of fine red clay, with numerous minute particles, some of volcanic, some of meteoric, origin, fragments of shooting stars, over 100,000,000 of which are said to strike the surface of our earth every year. How slow the process of deposition must be, may be inferred from the fact that the trawl sometimes brings up many teeth of Sharks and ear-bones of Whales (in one case no less than 600 teeth and 100 ear-bones), often semi-fossil, and which from their great density had remained intact for ages, long after all the softer parts had perished and disappeared.

The greatest depth of the Ocean appearsto coincide roughly with the greatest height of the mountains. There are indeed cases recorded in which it is said that "no bottom" was found even at 39,000 feet. It is, however, by no means easy to sound at such great depths, and it is now generally considered that these earlier observations are untrustworthy. The greatest depth known in the Atlantic is 3875 fathoms—a little to the north of the Virgin Islands, but the soundings as yet made in the deeper parts of the Ocean are few in number, and it is not to be supposed that the greatest depth has yet been ascertained.

In many parts of the world the geography itself has been modified by the enormous development of animal life. Most islands fall into one of three principal categories:

Firstly, Those which are in reality a part of the continent near which they lie, being connected by comparatively shallow water, and standing to the continent somewhat inthe relation of planets to the sun; as, for instance, the Cape de Verde Islands to Africa, Ceylon to India, or Tasmania to Australia.

Secondly, Volcanic islands; and

Thirdly, Those which owe their origin to the growth of Coral reefs.

Fig. 49.—Whitsunday Island.Fig. 49.—Whitsunday Island.

Coral islands are especially numerous in the Indian and Pacific Oceans, where there are innumerable islets, in the form of rings, or which together form rings, the rings themselves being sometimes made up of ringlets. These "atolls" contain a circular basin of yellowish green, clear, shallow water, while outside is the dark blue deep water of the Ocean. The islands themselves are quite low, with a beach of white sand rising but a fewfeet above the level of the water, and bear generally groups of tufted Cocoa Palms.

It used to be supposed that these were the summits of submarine volcanoes on which the coral had grown. But as the reef-making coral does not live at greater depths than about twenty-five fathoms, the immense number of these reefs formed an almost insuperable objection to this theory. The Laccadives and Maldives for instance—meaning literally the "lac of or 100,000 islands," and the "thousand islands"—are a series of such atolls, and it was impossible to imagine so great a number of craters, all so nearly of the same altitude.

In shallow tracts of sea, coral reefs no doubt tend to assume the well-known circular form, but the difficulty was to account for the numerous atolls which rise to the surface from the abysses of the ocean, while the coral-forming zoophytes can only live near the surface.

Darwin showed that so far from the ring of corals resting on a corresponding ridge of rocks, the lagoons, on the contrary,now occupy the place which was once the highest land. He pointed out that some lagoons, as for instance that of Vanikoro, contain an island in the middle; while other islands, such as Tahiti, are surrounded by a margin of smooth water separated from the ocean by a coral reef. Now if we suppose that Tahiti were to sink slowly it would gradually approximate to the condition of Vanikoro; and if Vanikoro gradually sank, the central island would disappear, while on the contrary the growth of the coral might neutralise the subsidence of the reef, so that we should have simply an atoll with its lagoon. The same considerations explain the origin of the "barrier reefs," such as that which runs for nearly a thousand miles, along the north-east coast of Australia. Thus Darwin's theory explains the form and the approximate identity of altitude of these coral islands. But it does more than this, because it shows that there are great areas in process of subsidence, which though slow, is of great importance in physical geography.

The lagoon islands have received much attention; which "is not surprising, for every one must be struck with astonishment, when he first beholds one of these vast rings of coral-rock, often many leagues in diameter, here and there surmounted by a low verdant island with dazzling white shores, bathed on the outside by the foaming breakers of the ocean, and on the inside surrounding a calm expanse of water, which, from reflection is generally of a bright but pale green colour. The naturalist will feel this astonishment more deeply after having examined the soft and almost gelatinous bodies of these apparently insignificant coral-polypifers, and when he knows that the solid reef increases only on the outer edge, which day and night is lashed by the breakers of an ocean never at rest. Well did François Pyrard de Laval, in the year 1605 exclaim, 'C'est une merveille de voir chacun de ces atollons, environné d'un grand banc de pierre tout autour, n'y ayant point d'artifice humain.'"[62]

Of the enchanting beauty of the coral bedsthemselves we are assured that language conveys no adequate idea. "There were corals," says Prof. Ball, "which, in their living state, are of many shades of fawn, buff, pink, and blue, while some were tipped with a magenta-like bloom. Sponges which looked as hard as stone spread over wide areas, while sprays of coralline added their graceful forms to the picture. Through the vistas so formed, golden-banded and metallic-blue fish meandered, while on the patches of sand here and there Holothurias and various mollusca and crustaceans might be seen slowly crawling."

Abercromby also gives a very graphic description of a Coral reef. "As we approached," he says, "the roaring surf on the outside, fingery lumps of beautiful live coral began to appear of the palest lavender-blue colour; and when at last we were almost within the spray, the whole floor was one mass of living branches of coral.

"But it is only when venturing as far as is prudent into the water, over the outward edge of the great sea wall, that the true character of the reef and all the beauties of the oceancan be really seen. After walking over a flat uninteresting tract of nearly bare rock, you look down and see a steep irregular wall, expanding deeper into the ocean than the eye can follow, and broken into lovely grottoes and holes and canals, through which small resplendent fish of the brightest blue or gold flit fitfully between the lumps of coral. The sides of these natural grottoes are entirely covered with endless forms of tender-coloured coral, but all beautiful, and all more or less of the fingery or branching species, known as madrepores. It is really impossible to draw or describe the sight, which must be taken with all its surroundings as adjuncts."[63]

The vegetation of these fairy lands is also very lovely; the Coral tree (Erythrina) with light green leaves and bunches of scarlet blossoms, the Cocoa-nut always beautiful, the breadfruit, the graceful tree ferns, the Barringtonia, with large pink and white flowers, several species of Convolvulus, and many others unknown to us even by name.

In considering these exquisite scenes, the beauty of the Southern skies must not be omitted. "From the time we entered the torrid zone," says Humboldt, "we were never wearied with admiring, every night, the beauty of the southern sky, which, as we advanced towards the south, opened new constellations to our view. We feel an indescribable sensation, when, on approaching the equator, and particularly on passing from one hemisphere to the other, we see those stars which we have contemplated from our infancy, progressively sink, and finally disappear. Nothing awakens in the traveller a livelier remembrance of the immense distance by which he is separated from his country, than the aspect of an unknown firmament. The grouping of the stars of the first magnitude, some scattered nebulæ rivalling in splendour the milky way, and tracts of space remarkable for their extreme blackness, give a particular physiognomy to the southern sky. This sight fills with admiration even those,who, uninstructed in the branches of accurate science, feel the same emotions of delight in the contemplation of the heavenly vault, as in the view of a beautiful landscape, or a majestic river. A traveller has no need of being a botanist to recognise the torrid zone on the mere aspect of its vegetation; and, without having acquired any notion of astronomy, he feels he is not in Europe, when he sees the immense constellation of the Ship, or the phosphorescent clouds of Magellan, arise on the horizon. The heaven and the earth, in the equinoctial regions, assume an exotic character."

"The sunsets in the Eastern Archipelago," says H. O. Forbes,[64]"were scenes to be remembered for a lifetime. The tall cones of Sibissie and Krakatoa rose dark purple out of an unruffled golden sea, which stretched away to the south-west, where the sun went down; over the horizon gray fleecy clouds lay in banks and streaks, above them pale blue lanes of sky, alternating with orange bands, which higher up gave place to an expanse ofred stretching round the whole heavens. Gradually as the sun retreated deeper and deeper, the sky became a marvellous golden curtain, in front of which the gray clouds coiled themselves into weird forms before dissolving into space...."

The Arctic and Antarctic regions have always exercised a peculiar fascination over the human mind. Until now every attempt to reach the North Pole has failed, and the South has proved even more inaccessible. In the north, Parry all but reached lat. 83; in the south no one has penetrated beyond lat. 71.11. And yet, while no one can say what there may be round the North Pole, and some still imagine that open water might be found there, we can picture to ourselves the extreme South with somewhat more confidence.

Whenever ships have sailed southwards, except at a few places where land has been met with, they have come at last to a wall of ice, from fifty to four hundred feet high. Inthose regions it snows, if not incessantly, at least very frequently, and the snow melts but little. As far as the eye can reach nothing is to be seen but snow. Now this snow must gradually accumulate, and solidify into ice, until it attains such a slope that it will move forward as a glacier. The enormous Icebergs of the Southern Ocean, moreover, show that it does so, and that the snow of the extreme south, after condensing into ice, moves slowly outward and at length forms a wall of ice, from which Icebergs, from time to time, break away. We do not exactly know what, under such circumstances, the slope would be; but Mr. Croll points out that if we take it at only half a degree, and this seems quite a minimum, the Ice cap at the South Pole must be no less than twelve miles in thickness. It is indeed probably even more, for some of the Southern tabular icebergs attain a height of eight hundred, or even a thousand feet above water, indicating a total thickness of the ice sheet even at the edge, of over a mile.

Sir James Ross mentions that—"Whilst measuring some angles for the survey nearMount Lubbock an island suddenly appeared, which he was quite sure was not to be seen two or three hours previously. He was much astonished, but it eventually turned out to be a large iceberg, which had turned over, and so exposed a new surface covered with earth and stones."

The condition of the Arctic regions is quite different. There is much more land, and no such enormous solid cap of ice. Spitzbergen, the land of "pointed mountains," is said to be very beautiful. Lord Dufferin describes his first view of it as "a forest of thin lilac peaks, so faint, so pale, that had it not been for the gem-like distinctness of their outline one could have deemed them as unsubstantial as the spires of Fairyland."

It is, however, very desolate; scarcely any vegetation excepting a dark moss, and even this goes but a little way up the mountain side. Scoresby ascended one of the hills near Horn Sound, and describes the view as "most extensive and grand. A fine sheltered bay was seen to the east of us, an arm of the same on the north-east, and the sea, whose glassysurface was unruffled by a breeze, formed an immense expanse on the west; the glaciers, rearing their proud crests almost to the tops of mountains between which they were lodged, and defying the power of the solar beams, were scattered in various directions about the sea-coast and in the adjoining bays. Beds of snow and ice filling extensive hollows, and giving an enamelled coat to adjoining valleys, one of which, commencing at the foot of the mountain where we stood, extended in a continual line towards the north, as far as the eye could reach—mountain rising above mountain, until by distance they dwindled into insignificance, the whole contrasted by a cloudless canopy of deepest azure, and enlightened by the rays of a blazing sun, and the effect, aided by a feeling of danger, seated as we were on the pinnacle of a rock almost surrounded by tremendous precipices—all united to constitute a picture singularly sublime."

One of the glaciers of Spitzbergen is 11 miles in breadth when it reaches the sea-coast, the highest part of the precipitous front adjoining the sea being over 400 feet, and itextends far upwards towards the summit of the mountain. The surface forms an inclined plane of smooth unsullied snow, the beauty and brightness of which render it a conspicuous landmark on that inhospitable shore. From the perpendicular face great masses of ice from time to time break away,

Whose blocks of sapphire seem to mortal eyeHewn from cærulean quarries of the sky.[65]

Field ice is comparatively flat, though it may be piled up perhaps as much as 50 feet. It is from glaciers that true icebergs, the beauty and brilliance of which Arctic travellers are never tired of describing, take their origin.

The attempts to reach the North Pole have cost many valuable lives; Willoughby and Hudson, Behring and Franklin, and many other brave mariners; but yet there are few expeditions more popular than those to "the Arctic," and we cannot but hope that it is still reserved for the British Navy after so many gallant attempts at length to reach the North Pole.

FOOTNOTES:[56]Shelley.[57]Campbell.[58]Holmes.[59]Bell.[60]Hemans.[61]Gunther,History of Fishes.[62]Darwin,Coral Reefs.[63]Abercromby,Seas and Skies in many Latitudes.[64]A Naturalist's Wanderings in the Eastern Archipelago.[65]Montgomery.

[56]Shelley.

[57]Campbell.

[58]Holmes.

[59]Bell.

[60]Hemans.

[61]Gunther,History of Fishes.

[62]Darwin,Coral Reefs.

[63]Abercromby,Seas and Skies in many Latitudes.

[64]A Naturalist's Wanderings in the Eastern Archipelago.

[65]Montgomery.

A man can hardly lift up his eyes towards the heavens without wonder and veneration, to see so many millions of radiant lights, and to observe their courses and revolutions, even without any respect to the common good of the Universe.—Seneca.

Many years ago I paid a visit to Naples, and ascended Vesuvius to see the sun rise from the top of the mountain. We went up to the Observatory in the evening and spent the night outside. The sky was clear; at our feet was the sea, and round the bay the lights of Naples formed a lovely semicircle. Far more beautiful, however, were the moon and the stars overhead; the moon throwing a silver path over the water, and the stars shining in that clear atmosphere with a brilliance which I shall never forget.

For ages and ages past men have admired the same glorious spectacle, and yet neither the imagination of Man nor the genius of Poetry had risen to the truer and granderconceptions of the Heavens for which we are indebted to astronomical Science. The mechanical contrivances by which it was attempted to explain the movements of the heavenly bodies were clumsy and prosaic when compared with the great discovery of Newton. Ruskin is unjust I think when he says "Science teaches us that the clouds are a sleety mist; Art, that they are a golden throne." I should be the last to disparage the debt we owe to Art, but for our knowledge, and even more, for our appreciation, feeble as even yet it is, of the overwhelming grandeur of the Heavens, we are mainly indebted to Science.

There is scarcely a form which the fancy of Man has not sometimes detected in the clouds,—chains of mountains, splendid cities, storms at sea, flights of birds, groups of animals, monsters of all kinds,—and our superstitious ancestors often terrified themselves by fantastic visions of arms and warriors and battles which they regarded as portents of coming calamities. There is hardly a day on which Clouds do not delight and surprise us by their forms and colours. They belong, however, to our Earth, and I must now pass on to the heavenly bodies.

THE MOON.THE MOON.To face page 377.

The Moon is the nearest, and being the nearest, appears to us, with the single exception of the Sun, the largest, although it is in reality one of the smallest, of the heavenly bodies. Just as the Earth goes round the Sun, and the period of revolution constitutes a year, so the Moon goes round the Earth approximately in a period of one month. But while we turn on our axis every twenty-four hours, thus causing the alternation of light and darkness—day and night—the Moon takes a month to revolve on hers, so that she always presents the same, or very nearly the same, surface to us.

Seeing her as we do, not like the Sun and Stars, by light of her own, but by the reflected light of the Sun, her form appears to change, because the side upon which the Sun shines is not always that which we see. Hence the"phases" of the Moon, which add so much to her beauty and interest.

Who is there who has not watched them with admiration? "We first see her as an exquisite crescent of pale light in the western sky after sunset. Night after night she moves further and further to the east, until she becomes full, and rises about the same time that the Sun sets. From the time of full moon the disc of light begins to diminish, until the last quarter is reached. Then it is that the Moon is seen high in the heavens in the morning. As the days pass by, the crescent shape is again assumed. The crescent wanes thinner and thinner as the Moon draws closer to the Sun. Finally, she becomes lost in the overpowering light of the Sun, again to emerge as the new moon, and again to go through the same cycle of changes."[66]

But although she is so small the Moon is not only, next to the Sun, by far the most beautiful, but also for us the most important, of the heavenly bodies. Her attraction, aided by that of the Sun, causes the tides, whichare of such essential service to navigation. They carry our vessels in and out of port, and, indeed, but for them many of our ports would themselves cease to exist, being silted up by the rivers running into them. The Moon is also of invaluable service to sailors by enabling them to determine where they are, and guiding them over the pathless waters.

The geography of the Moon, so far as concerns the side turned towards us, has been carefully mapped and studied, and may almost be said to be as well known as that of our own earth. The scenery is in a high degree weird and rugged; it is a great wilderness of extinct volcanoes, and, seen with even a very moderate telescope, is a most beautiful object. The mountains are of great size. Our loftiest mountain, Mount Everest, is generally stated as about 29,000 feet in height. The mountains of the Moon reach an altitude of over 42,000, but this reckons to the lowest depression, and it must be remembered that we reckon the height of mountains to the sea level only. Several of the craters on the Moon have a diameter of 40 or 50—one ofthem even as much as 78—miles. Many also have central cones, closely resembling those in our own volcanic regions. In some cases the craters are filled nearly to the brim with lava. The volcanoes seem, however, to be all extinct; and there is not a single case in which we have conclusive evidence of any change in a lunar mountain.

Fig. 50.—A group of Lunar Volcanoes.Fig. 50.—A group of Lunar Volcanoes.

The Moon, being so much smaller than the earth, cooled, of course, much more rapidly, and it is probable that these mountains are millions of years old—much older than manyof our mountain chains. Yet no one can look at a map of the Moon without being struck with the very rugged character of its mountain scenery. This is mainly due to the absence of air and water. To these two mighty agencies, not merely "the cloud-capped towers, the gorgeous palaces, the solemn temples," but the very mountains themselves, are inevitable victims. Not merely storms and hurricanes, but every gentle shower, every fall of snow, tends to soften our scenery and lower the mountain peaks. These agencies are absent from the Moon, and the mountains stand to-day just as they were formed millions of years ago.

But though we find on our own globe (see, for instance, Fig. 21) volcanic regions closely resembling those of the Moon, there are other phenomena on the Moon's surface for which our earth presents as yet no explanation. From Tycho, for instance, a crater 17,000 feet high and 50 miles across, a number of rays or streaks diverge, which for hundreds, or in some cases two or three thousand, miles pass straight across plains, craters, and mountains.The true nature of these streaks is not yet understood.

The Sun is more than 400 times as distant as the Moon; a mighty glowing globe, infinitely hotter than any earthly fiery furnace, 300,000 times as heavy, and 1,000,000 times as large as the earth. Its diameter is 865,000 miles, and it revolves on its axis in between 25 and 26 days. Its distance is 92,500,000 miles. And yet it is only a star, and by no means one of the first magnitude.

The surface of the Sun is the seat of violent storms and tempests. From it gigantic flames, consisting mainly of hydrogen, flicker and leap. Professor Young describes one as being, when first observed, 40,000 miles high. Suddenly it became very brilliant, and in half an hour sprang up 40,000 more. For another hour it soared higher and higher, reaching finally an elevation of no less than 350,000 miles, after which it slowly faded away, and in a couple of hours had entirely disappeared. This was no doubt an exceptionalcase, but a height of 100,000 miles is not unusual, and the velocity frequently reaches 100 miles in a second.

The proverbial spots on the Sun in many respects resemble the appearances which would be presented if a comparatively dark central mass was here and there exposed by apertures through the more brilliant outer gases, but their true nature is still a matter of discussion.

During total eclipses it is seen that the Sun is surrounded by a "corona," or aureola of light, consisting of radiant filaments, beams, and sheets of light, which radiate in all directions, and the true nature of which is still doubtful.

Another stupendous problem connected with the Sun is the fact that, as geology teaches us, it has given off nearly the same quantity of light and heat for millions of years. How has this come to pass? Certainly not by any process of burning such as we are familiar with. Indeed, if the heat of the Sun were due to combustion it would be burnt up in 6000 years. It has been suggested thatthe meteors, which fall in showers on to the Sun, replace the heat which is emitted. To some slight extent perhaps they do so, but the main cause seems to be the slow condensation of the Sun itself. Mathematicians tell us that a contraction of about 220 feet a year would account for the whole heat emitted, and as the present diameter of the Sun is about 860,000 miles, the potential store of heat is still enormous.

To the Sun we owe our light and heat; it is not only the centre of our planetary system, it is the source and ruler of our lives. It draws up water from the ocean, and pours it down in rain to fill the rivers and refresh the plants; it raises the winds, which purify the air and waft our ships over the seas; it draws our carriages and drives our steam-engines, for coal is but the heat of former ages stored up for our use; animals live and move by the Sun's warmth; it inspires the song of birds, paints the flowers, and ripens the fruit. Through it the trees grow. For the beauties of nature, for our food and drink, for our clothing, for our light and life, for the verypossibility of our existence, we are indebted to the Sun.

What is the Sun made of? Comte mentioned as a problem, which it was impossible that man could ever solve, any attempt to determine the chemical composition of the heavenly bodies. "Nous concevons," he said, "la possibilité de déterminer leurs formes, leurs distances, leurs grandeurs, et leurs mouvements, tandis que nous ne saurions jamais étudier par aucun moyen leur composition chimique ou leur structure minéralogique." To do so might well have seemed hopeless, and yet the possibility has been proved, and a beginning has been made. In the early part of this century Wollaston observed that the bright band of colours thrown by a prism, and known as the spectrum, was traversed by dark lines, which were also discovered, and described more in detail, by Fraunhofer, after whom they are generally called "Fraunhofer's lines." The next step was made by Wheatstone, who showed that the spectrum formed by incandescent vapours was formed of bright lines, which differed for each substance, andmight, therefore, be used as a convenient mode of analysis. In fact, by this process several new substances have actually been discovered. These bright lines were found on comparison to coincide with the dark lines in the spectrum, and to Kirchhoff and Bunsen is due the credit of applying this method of research to astronomical science. They arranged their apparatus so that one-half was lighted by the Sun, the other by the incandescent gas they were examining. When the vapour of sodium was treated in this way they found that the bright line in the flame of soda exactly coincided with a line in the Sun's spectrum. The conclusion was obvious; there is sodium in the Sun. It must, indeed, have been a glorious moment when the thought flashed upon them; and the discovery, with its results, is one of the greatest triumphs of human genius.

The Sun has thus been proved to contain hydrogen, sodium, barium, magnesium, calcium, aluminium, chromium, iron, nickle, manganese, titanium, cobalt, lead, zinc, copper, cadmium, strontium, cerium, uranium, potassium,etc., in all 36 of our terrestrial elements, while as regards some others the evidence is not conclusive. We cannot as yet say that any of our elements are absent, nor though there are various lines which cannot as yet be certainly referred to any known substance, have we clear proof that the Sun contains any element which does not exist on our earth. On the whole, then, the chemical composition of the Sun appears closely to resemble that of our earth.

The Syrian shepherds watching their flocks by night long ago noticed—and they were probably not the first—that there were five stars which did not follow the regular course of the rest, but, apparently at least, moved about irregularly. These they appropriately named Planets, or wanderers.

Further observations have shown that this irregularity of their path is only apparent, and that, like our own Earth, they really revolve round the Sun. To the five first observed—Mercury,Venus, Mars, Jupiter, and Saturn—two large ones, Uranus and Neptune, and a group of minor bodies, have since been added.

The following two diagrams give the relative orbits of the Planets.

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