My worthy uncle, the Professor, saw clearly that my legs refused further service, and that, in fact, I was utterly exhausted. Despite his hot and feverish impatience, he decided, with a sigh, upon a halt. He called the eider-duck hunter to his side. That worthy, however, shook his head. "Ofvanfor," was his sole spoken reply. "It appears," says my uncle with a woebegone look, "that we must go higher." He then turned to Hans, and asked him to give some reason for this decisive response. "Mistour," replied the guide. "Ja, mistour--yes, the mistour," cried one of the Icelandic guides in a terrified tone. It was the first time he had spoken. "What does this mysterious word signify?" I anxiously inquired. "Look," said my uncle. I looked down upon the plain below, and I saw a vast, a prodigious volume of pulverized pumice stone, of sand, of dust, rising to the heavens in the form of a mighty waterspout. It resembled the fearful phenomenon of a similar character known to the travelers in the desert of the great Sahara. The wind was driving it directly towards that side of Sneffels on which we were perched. This opaque veil standing up between us and the sun projected a deep shadow on the flanks of the mountain. If this sand spout broke over us, we must all be infallibly destroyed, crushed in its fearful embraces. This extraordinary phenomenon, very common when the wind shakes the glaciers, and sweeps over the arid plains, is in the Icelandic tongue called "mistour." "Hastigt, hastigt!" cried our guide. Now I certainly knew nothing of Danish, but I thoroughly understood that his gestures were meant to quicken us. The guide turned rapidly in a direction which would take us to the back of the crater, all the while ascending slightly. We followed rapidly, despite our excessive fatigue. A quarter of an hour later Hans paused to enable us to look back. The mighty whirlwind of sand was spreading up the slope of the mountain to the very spot where we had proposed to halt. Huge stones were caught up, cast into the air, and thrown about as during an eruption. We were happily a little out of the direction of the wind, and therefore out of reach of danger. But for the precaution and knowledge of our guide, our dislocated bodies, our crushed and broken limbs, would have been cast to the wind, like dust from some unknown meteor. Hans, however, did not think it prudent to pass the night on the bare side of the cone. We therefore continued our journey in a zigzag direction. The fifteen hundred feet which remained to be accomplished took us at least five hours. The turnings and windings, the no-thoroughfares, the marches and marches, turned that insignificant distance into at least three leagues. I never felt such misery, fatigue and exhaustion in my life. I was ready to faint from hunger and cold. The rarefied air at the same time painfully acted upon my lungs.