Bartram and his little son, while they were talking thus, sat watching the same lime-kiln that had been the scene of Ethan Brand's solitary and meditative life, before he began his search for the Unpardonable Sin. Many years, as we have seen, had now elapsed, since that portentous night when the Idea was first developed. The kiln, however, on the mountain-side, stood unimpaired, and was in nothing changed since he had thrown his dark thoughts into the intense glow of its furnace, and melted them, as it were, into the one thought that took possession of his life. It was a rude, round, tower-like structure, about twenty feet high, heavily built of rough stones, and with a hillock of earth heaped about the larger part of its circumference; so that the blocks and fragments of marble might be drawn by cart-loads, and thrown in at the top. There was an opening at the bottom of the tower, like an oven-mouth, but large enough to admit a man in a stooping posture, and provided with a massive iron door. With the smoke and jets of flame issuing from the chinks and crevices of this door, which seemed to give admittance into the hillside, it resembled nothing so much as the private entrance to the infernal regions, which the shepherds of the Delectable Mountains were accustomed to show to pilgrims. There are many such lime-kilns in that tract of country, for the purpose of burning the white marble which composes a large part of the substance of the hills. Some of them, built years ago, and long deserted, with weeds growing in the vacant round of the interior, which is open to the sky, and grass and wild-flowers rooting themselves into the chinks of the stones, look already like relics of antiquity, and may yet be overspread with the lichens of centuries to come. Others, where the lime-burner still feeds his daily and night-long fire, afford points of interest to the wanderer among the hills, who seats himself on a log of wood or a fragment of marble, to hold a chat with the solitary man. It is a lonesome, and, when the character is inclined to thought, may be an intensely thoughtful occupation; as it proved in the case of Ethan Brand, who had mused to such strange purpose, in days gone by, while the fire in this very kiln was burning.