Except for a small tribute in the shape of fish food and certain salts the ocean is to-day almost a dead loss to the world, and what is worse, the greatest of all obstacles to progress. It separates us from our kin, wrecks our ships, claims a yearly toll of dead, and is barren, fruitless, a mere receptacle for garbage. A hundred years hence we shall have awakened to these facts and found means to make “the caverns vast of ocean old” something better than a subject for the poet and a resting-place for the dead whom it murders.

Not every dream, however, can be realised—not even the engineer’s. Some years ago certain ardent spirits in France announced that the desert of Sahara lay below the level of the sea and could be flooded with the Atlantic or Mediterranean. The effect of this, it was considered, would not merely be to inconvenience certain Arabs, but to change entirely the climate of the rest of equatorial Africa. Laved by the beneficent waves of ocean, lands at present uninhabitable would, it was declared, become fertile and salubrious. The project was dismissed or shelved as impracticable from engineering difficulties. Shall we, a hundred years hence, have met these difficulties?

Probably not. To work such changes in the distribution of land and water will be a thing not indeed beyond the power of the next century’s engineers, but beyond their daring. The accomplishment of them might, if at all rapid, be attended by frightful disasters, some of which can be readily estimated, but of which the worst would probably remain unforeseen and unimagined until the irrevocable moment of fulfilment. To increase to this extent the area of the world’s oceans, without increasing (as of course we could not increase) their mass, would perceptibly lower the level of the sea everywhere, and in accordance with the well-known hydrostatic law things would “right themselves” on a cataclysmal scale. Every narrow strait in the world, every oceanic canal would become, for the time being, a roaring cataract. The Mediterranean would rush tumultuously out through the Straits of Gibraltar and the Suez Canal, and the overflow would flood the adjacent lands. The Straits of Dover would roar like Niagara, and all Kent, and the low-lying north-east corner of France, would be devastated. The isthmus of Panama might at the same time be swept away, for the narrow banks of the completed Panama Canal would certainly give way before the weight of the two oceans. All the rivers of the world would rush down in spate until they ran nearly dry from the increased outfall. The sea would recede from all the coasts. Along with this fall in the level of the sea would come tempests such as, since the appearance of man on the planet, the world has never known. For the sea-supported atmosphere would suck into its vacuum the whole weight of the over-lying air until pressure was equalised. And the climate of all the world would be reconstituted in new and probably inconvenient ways.

No. We cannot venture thus to change the face of creation. What we can and shall do is to make the best of it. In a hundred years’ time many countries at present undeveloped will be rich and populous. Canada, for one example, has an area greater than that of the United States, with a population smaller than the population of Greater London. And Canada, endowed as it is with almost every source of wealth, will before long become perhaps the richest country in the world. By this time next century it will also be one of the most populous. Siberia, again, with many fertile and salubrious tracts, will certainly have been more intelligently utilised than by making a vast prison of it. But when all the regions available for human habitation are populated and made use of, the centres of civilisation will probably lie very much where they lie now; and here the congested populations will have found that they can no longer tolerate the waste of a neglected ocean. As we push outward from the centre of the continents, the seaboard will have to be utilised and extended. There is nothing to daunt the engineers of a hundred years hence in the project of erecting on the sea a vast floating city, fully as convenient as the present cities of terra firma, and, while vastly more healthful, quite substantial enough to resist storm and every motion of the sea, except the tides on which the city will rise and fall—tides which will no doubt furnish the motive power of many conveniences in ocean cities.

There are great advantages in a city thus founded, as compared with those we at present inhabit; and we certainly shall not be able to neglect them. There will be no particular reason for economy of space or for insalubrious overcrowding (since the sea has no landlord), and breadth would make for stability as well as for convenience. Urban traffic will employ an entirely new light vehicle, the skimmer. It has been mentioned as a thing beyond doubt that the ships of a hundred years hence will no longer float in the sea, but ride on its surface, thus evading both the instability and the resistance at present so troublesome to marine engineers. As soon as the necessity arises for providing street traffic in the ocean city—when “the sea is in the broad, the narrow streets, ebbing and flowing, and the salt weed clings to the marble of her palaces”—invention will meet the demand, and light street waggons and carriages will everywhere glide about, performing the daily needs of the inhabitants. Something in the nature of break-waters will provide against wave-play and form an unequalled exterior boulevard; and by means of an invention which will long since have been called for by the requirements of other localities, the air of dwelling-houses in the ocean city will be wholesomely freed from damp.

For we shall certainly not have failed to act upon our knowledge of the fact that irregularities in the proportion of atmospheric moisture are responsible for the unhealthiness of certain areas; and we shall have learned, by means of the anhydrator, to provide any place with exactly the degree of damp or dryness necessary to health. The same apparatus, by desiccating the air to the extreme point, will keep the houses of an ocean city dry and thus do away with an objection which would make homes built on the water insufferable to-day.

If we have not wholly reformed throughout the world our system of land tenure, the conquered ocean will unquestionably relieve the tension which is created by it, and perhaps a radical change of this character will only become possible when the enormous advantages of it have been practically exemplified.

But there is another way in which the conquest of ocean ought to prove a great economic boon to the world. Except in the case of a few coal mines, with shafts sunk near the sea beach, we have hardly at all begun to investigate the contents of the ocean floor. There is, so far as I am aware, no particular reason to doubt that the constitution of the subterranean world is in most respects very much the same under the sea as under the land. Probably vast riches, as yet undreamed of, lie below the surface of the ocean and beneath its floor. There can be no question that the needs of the world will make us eager to tap them, as we should already have begun to, if any way could be discovered of overcoming the engineering difficulties involved. These difficulties, in the present state of our knowledge, may well appal the stoutest imagination. The problem presented by the immense and paralysing air pressure in a mine at this great depth would have to be overcome. Even in some great terrestrial excavations already made the problem occurs: and where (as in river tunnels and elsewhere) men attempt to work in great air-pressures artificially induced, the phenomenon called caisson-disease occasions practical difficulty. But the mere fact of an achievement being almost inconceivable in the light of present knowledge and invention must not be allowed to put a clog upon a forecast of what next century may attain. It is a hypothesis which the reader has been invited to accept, not merely that discovery and invention will go on, but that they will go at a constantly-increasing pace. We must not, therefore, allow what may well seem, at the present day, insuperable engineering difficulties to forbid the belief that the undiscovered wealth of the earth below the sea will be tapped for the benefit of the new age. What minerals may lie there, a rich heirloom for the coming time, we can but roughly imagine. But enterprise and the world’s necessities will spur us on to search them out, until the new people, deriving like a fresh AntÆus constant stores of strength from Mother Earth, will enter into possessions which must vastly relieve their necessities. Individual enterprise will solve the problems and reap its store of profits. But the ocean is no-man’s land, and the people—perhaps a world-people, for this purpose at least not subdivided into antagonistic communities—will beyond doubt take toll, for the relief of general taxation, from the earnings of the new mineralogy.

In other ways, too, the sea itself will be made use of. We shall get our salt from it, the process of separation being electrolytic. Fish will probably be eaten later than any other form of animal food. But the chief gift of the sea to the life of the future will be the two gases of which water is composed—oxygen and hydrogen: and the other gas, chlorine, which forms half the salt, as well as the metal sodium which forms the other half, will probably have many new uses found for them. Liquefied oxygen will no doubt be our sole disinfectant. It will also replace the poisonous, noisome and destructive bleaching agents used to-day. Hydrogen, the lightest of all gases, will be another staple of commerce. It will (as we have elsewhere seen) probably be the only fuel employed, for its combustion furnishes the greatest heat terrestrially known, and its flame is smokeless and yields no poisonous by-product. Moreover, the evaporation of liquid hydrogen, by a sort of curious revenge, produces the greatest available cold. If anything in the nature of balloons should survive the century hydrogen will inflate them, and both our hydrogen and our oxygen will most likely be got by preference from the sea. There are many reasons for this preference. Probably there will be some advantage in the matter of expense, since the salts of ocean water would be a by-product of the operation, and it is conceivable that a use may be found for the rarer among them, which could only be obtained in satisfactory quantities by reducing to dryness huge amounts of water. And potable or spring waters will perhaps be too precious a commodity to be consumed unnecessarily. Distilled water could no doubt be used for drinking purposes, and bacteriologically it is of course unexceptionable; but there are certain objections to it, and though these may doubtless be overcome, natural waters have a value which cannot be ignored.

Thus the oceans of the world, as yet mere watery deserts, useful to hardly a calculable percentage of the people (and then only at the expense of the rest) will have become the world’s inheritance, and its hoarded wealth will stave off the time—whose coming we must not ignore—when our world-capital begins to be exhausted. For that time must come. We are living upon the hoards which the womb of our mother the earth has borne to our father the sun. But our mother is, in respect at all events of mineral wealth, past the age of conception; and every century brings us more rapidly near to the time when we shall, like spendthrifts, have lived out our capital. Already the end of coal is in sight. When, at the end of a vista however long, we begin to be able to foresee the exhaustion of other minerals, we shall face a problem appalling in its nature. Perhaps before our store of heat gives out and reduces earth to the state of a dead world like the moon, we shall already have exhausted our stock. No economies in the use of scrap metal and the re-employment of the material of machines which have been superseded can save us from ultimate metallic bankruptcy in a future calculated perhaps in thousands (but not many thousands) of years. Our only succour seems to lie in a conception for which (despite the efforts of some lively thinkers who have been obliged to ignore all but the least important difficulties of the subject) we have no material—the conception of means by which the cold depths of interplanetary space may be traversed. Even if we allow imagination, untrammelled by the most evident necessities of the case, to suggest a speed of transport computable only by astronomical analogies, we still lag behind anything which could serve this purpose, unless we concurrently believe that human life shall, by that time, be lengthened into centuries. Otherwise, however recklessly we may conceive of speed in interplanetary travel, man would almost require to live for many centuries in order to reach and return from any destination which would not inevitably destroy him by fire or cold when he arrived at it. Most likely man is for ever destined to accept the bounds of his own planet, and to be limited by its resources. In order that these resources may be utilised to the uttermost of his needs, the contents of the ocean floor must undoubtedly be laid under contribution, and probably we shall not antedate this achievement if we consider that it will have been at least entered upon a hundred years hence.