Essays - Henry David Thoreau (best e reader for android .TXT) 📗

equal to 72,000 millions of men, or for every mile of coast, a power of 24,000,000 men.

“Rafts, of any extent, fastened on the ground of the sea, along the shore, and stretching far into the sea, may be covered with fertile soil, bearing vegetables and trees, of every description, the finest gardens, equal to those the firm land may admit of, and buildings and machineries, which may operate, not only on the sea, where they are, but which also, by means of mechanical connections, may extend their operations for many miles into the continent. (Etzler’s Mechanical System, page 24.) Thus this power may cultivate the artificial soil for many miles upon the surface of the sea, near the shores, and, for several miles, the dry land, along the shore, in the most superior manner imaginable; it may build cities along the shore, consisting of the most magnificent palaces, every one surrounded by gardens and the most delightful sceneries; it may level the hills and unevennesses, or raise eminences for enjoying open prospect into the country and upon the sea; it may cover the barren shore with fertile soil, and beautify the same in various ways; it may clear the sea of shallows, and make easy the approach to the land, not merely of vessels, but of large floating islands, which may come from, and go to distant parts of the world, islands that have every commodity and security for their inhabitants which the firm land affords.”

“Thus may a power, derived from the gravity of the moon and the ocean, hitherto but the objects of idle curiosity to the studious man, be made eminently subservient for creating the most delightful abodes along the coasts, where men may enjoy at the same time all the advantages of sea and dry land; the coasts may hereafter be continuous paradisiacal skirts between land and sea, everywhere crowded with the densest population. The shores and the sea along them will be no more as raw nature presents them now, but everywhere of easy and charming access, not even molested by the roar of waves, shaped as it may suit the purposes of their inhabitants; the sea will be cleared of every obstruction to free passage everywhere, and its productions in fishes, etc., will be gathered in large, appropriate receptacles, to present them to the inhabitants of the shores and of the sea.”

Verily, the land would wear a busy aspect at the spring and neap tide, and these island ships⁠—these terra infirma⁠—which realise the fables of antiquity, affect our imagination. We have often thought that the fittest locality for a human dwelling was on the edge of the land, that there the constant lesson and impression of the sea might sink deep into the life and character of the landsman, and perhaps impart a marine tint to his imagination. It is a noble word, that mariner⁠—one who is conversant with the sea. There should be more of what it signifies in each of us. It is a worthy country to belong to⁠—we look to see him not disgrace it. Perhaps we should be equally mariners and terreners, and even our Green Mountains need some of that sea-green to be mixed with them.

The computation of the power of the Waves is less satisfactory. While only the average power of the wind and the average height of the tide were taken before, now the extreme height of the waves is used, for they are made to rise ten feet above the level of the sea, to which, adding ten more for depression, we have twenty feet, or the extreme height of a wave. Indeed, the power of the waves, which is produced by the wind blowing obliquely and at disadvantage upon the water, is made to be, not only three thousand times greater than that of the tide, but one hundred times greater than that of the wind itself, meeting its object at right angles. Moreover, this power is measured by the area of the vessel, and not by its length mainly, and it seems to be forgotten that the motion of the waves is chiefly undulatory, and exerts a power only within the limits of a vibration, else the very continents, with their extensive coasts, would soon be set adrift.

Finally, there is the power to be derived from sunshine, by the principle on which Archimedes contrived his burning-mirrors, a multiplication of mirrors reflecting the rays of the sun upon the same spot, till the requisite degree of heat is obtained. The principal application of this power will be to the boiling of water and production of steam.

“How to create rivulets of sweet and wholesome water, on floating islands, in the midst of the ocean, will be no riddle now. Seawater changed into steam, will distill into sweet water, leaving the salt on the bottom. Thus the steam engines on floating islands, for their propulsion and other mechanical purposes, will serve, at the same time, for the distillery of sweet water, which, collected in basins, may be led through channels over the island, while, where required, it may be refrigerated by artificial means, and changed into cool water, surpassing, in salubrity, the best spring water, because nature hardly ever distils water so purely, and without admixture of less wholesome matter.”

So much for these few and more obvious powers, already used to a trifling extent. But there are innumerable others in nature, not described nor discovered. These, however, will do for the present. This would be to make the sun and the moon equally our satellites. For, as the moon is the cause of the tides, and the sun the cause of the wind, which, in turn, is the cause of the waves, all the work of this planet would be performed by these far influences.

“But as these powers are very irregular and subject to interruptions; the next object is to show how they may be converted into powers that operate continually and uniformly forever, until the machinery be