The alchemist, still in the trance, arose, and leaned over the brazier. Something flaky and white and inflammable was tucked close to the bottom to act as kindling, and a coal brought from a farther brazier and laid upon this. It turned all black for a minute, then sizzled into an intense heat and ignited the brazier’s contents. The flame was at first yellow and creeping, then it changed to blue and leaping. Kreutz put a vessel filled with sulphur into the flames, and sure enough in a moment the spirit of the sulphur arose in fumes that filled the room. Both leaned over the brazier eagerly as the alchemist shook mercury over the melted sulphur. As the parchment had decreed, so the reaction followed; in a short time the glittering mercury had mingled with the melted sulphur and became an ugly black substance. Tring handed to Kreutz another vessel which was closed at the top. Kreutz shook the hot material from the first vessel into the second and put the latter back on the brazier. In all his motions he acted mechanically as if he were but working out the will of another. He opened this second vessel after a few seconds and, sure enough, the black substance was becoming a lively red. “The niter; the niter,” exclaimed Tring eagerly at his elbow. The alchemist took the package from his hands and tossed it into the substance now seething with heat. As he did so, as if obeying some unconscious instinct of self-preservation, he leaped back into the middle of the room and drew Tring with him. The exclamation of anger on Tring’s lips was cut in half, for at that instant the loft of the house rocked in a terrific explosion! “Quick, seize the crystal and descend!” screamed Tring, who was already speeding through the doorway, frantically wiping sparks of fire from his clothing. The exploding substances had sent their flames into the dry roof and walls of the house, and fire was leaping through them merrily. Everything in the room was beginning to blaze, and in two minutes more it would have been impossible to leave. The alchemist, still in a daze, took the crystal as he had been commanded, and made for the stairway. The stone gleamed in his hands like a million diamonds, rubies, and emeralds where the flames fell upon it, and he clutched it with all the strength of his right hand as he clung to the stair rail with his left, now swaying out over the court like a drunken man, now regaining his hold and descending another stair. But the student had been more nimble, and by the time that the alchemist had descended to the third floor of the house, Johann was down the stairs and through the gate, calling with all his might for the watch to notify the water master that the house above him was in flames. No watch was in sight and so he sought one at full speed, and while he was searching, Pan Kreutz had reached the open door and disappeared in the night, the Great Tarnov Crystal hidden under the folds of his black gown.