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.