For this marvellous city, of which such legends are related, was after all only of brick, and when the ivy grew over and trees and shrubs sprang up, and, lastly, the waters underneath burst in, this huge metropolis was soon overthrown. At this day all those parts which were built upon low ground are marshes and swamps. Those houses that were upon high ground were, of course, like the other towns, ransacked of all they contained by the remnant that was left; the iron, too, was extracted. Trees growing up by them in time cracked the walls, and they fell in. Trees and bushes covered them; ivy and nettles concealed the crumbling masses of brick.
The same was the case with the lesser cities and towns whose sites are known in the woods. For though many of our present towns bear the ancient names, they do not stand upon the ancient sites, but are two or three, and sometimes ten miles distant. The founders carried with them the name of their original residence.
Thus the low-lying parts of the mighty city of London became swamps, and the higher grounds were clad with bushes. The very largest of the buildings fell in, and there was nothing visible but trees and hawthorns on the upper lands, and willows, flags, reeds, and rushes on the lower. These crumbling ruins still more choked the stream, and almost, if not quite, turned it back. If any water ooze past, it is not perceptible, and there is no channel through to the salt ocean. It is a vast stagnant swamp, which no man dare enter, since death would be his inevitable fate.
There exhales from this oozy mass so fatal a vapour that no animal can endure it. The black water bears a greenish-brown floating scum, which forever bubbles up from the putrid mud of the bottom. When the wind collects the miasma, and, as it were, presses it together, it becomes visible as a low cloud which hangs over the place. The cloud does not advance beyond the limit of the marsh, seeming to stay there by some constant attraction; and well it is for us that it does not, since at such times when the vapour is thickest, the very wildfowl leave the reeds, and fly from the poison. There are no fishes, neither can eels exist in the mud, nor even newts. It is dead.
The flags and reeds are coated with slime and noisome to the touch; there is one place where even these do not grow, and where there is nothing but an oily liquid, green and rank. It is plain there are no fishes in the water, for herons do not go thither, nor the kingfishers, not one of which approaches the spot. They say the sun is sometimes hidden by the vapour when it is thickest, but I do not see how any can tell this, since they could not enter the cloud, as to breathe it when collected by the wind is immediately fatal. For all the rottenness of a thousand years and of many hundred millions of human beings is there festering under the stagnant water, which has sunk down into and penetrated the earth, and floated up to the surface the contents of the buried cloacae.
Many scores of men have, I fear, perished in the attempt to enter this fearful place, carried on by their desire of gain. For it can scarcely be disputed that untold treasures lie hidden therein, but guarded by terrors greater than fiery serpents. These have usually made their endeavours to enter in severe and continued frost, or in the height of a drought. Frost diminishes the power of the vapour, and the marshes can then, too, be partially traversed, for there is no channel for a boat. But the moment anything be moved, whether it be a bush, or a willow, even a flag, if the ice be broken, the pestilence rises yet stronger. Besides which, there are portions which never freeze, and which may be approached unawares, or a turn of the wind may drift the gas towards the explorer.
In the midst of summer, after long heat, the vapour rises, and is in a degree dissipated into the sky, and then by following devious ways an entrance may be effected, but always at the cost of illness. If the explorer be unable to quit the spot before night, whether in summer or winter, his death is certain. In the earlier times some bold and adventurous men did indeed succeed in getting a few jewels, but since then the marsh has become more dangerous, and its pestilent character, indeed, increases year by year, as the stagnant water penetrates deeper. So that now for very many years no such attempts have been made.
The extent of these foul swamps is not known with certainty, but it is generally believed that they are, at the widest, twenty miles across, and that they reach in a winding line for nearly forty. But the outside parts are much less fatal; it is only the interior which is avoided.
Towards the Lake the sand thrown up by the waves has long since formed a partial barrier between the sweet water and the stagnant, rising up to within a few feet of the surface. This barrier is overgrown with flags and reeds, where it is shallow. Here it is possible to sail along the sweet water within an arrow-shot of the swamp. Nor, indeed, would the
