Ere long a change came over the scene.  About two-thirds of the distance round the verge of the horizon a faint light appeared, resembling the scene when a dense curtain of clouds hangs over head, and the rays of the morning sun steal under the edge of the thick vapour.  But the stars could be seen, and the only appearance of clouds was immediately above the circle of light.  In a very few minutes the terrible truth flashed upon the mind of Glenn.  The dim light along the horizon was changed to an approaching flame!  Columns of smoke could be seen rolling upwards, while the fire beneath imparted a lurid glare to them.  The wind blew more fiercely, and the fire approached from almost every quarter with the swiftness of a race horse.  The darkened vault above became gradually illuminated with a crimson reflection, and the young man shuddered with the horrid apprehension of being burnt alive!  It was madness to proceed in a direction that must inevitably hasten their fate, the fire extending in one unbroken line from left to right, and in front of them; and they turned in a course which seemed to place the greatest distance between them and the furious element.  Ever and anon a frightened deer or elk leaped past.  The hounds no longer noticed them, but remained close to the horses.  The leaping flames came in awful rapidity.  The light increased in brilliance, and objects were distinguishable far over the prairie.  A red glare could be seen on the sides of the deer as they bounded over the tall, dry grass, which was soon to be no longer a refuge for them.  The young men heard a low, continued roar, that increased every moment in loudness, and looking in the direction whence they supposed it proceeded, they observed an immense, dark, moving mass, the nature of which they could not divine, but it threatened to annihilate every thing that opposed it.  While gazing at this additional source of danger, the horses, blinded by the surrounding light, plunged into a deep ditch that the rain had washed in the rich soil.  Neither men nor horses, fortunately, were injured; and after several ineffectual efforts to extricate themselves, they here resolved to await the coming of the fire.  Ringwood and Jowler whined fearfully on the verge of the ditch for an instant, and then sprang in and crouched trembling at the feet of their master.  The next instant the dark, thundering mass passed over head, being nothing less than an immense herd of buffalo driven forwards by the flames!  The horses bowed their heads as if a thunderbolt was passing.  The fire and the heavens were hid from view, and the roar above resembled the rush of mighty waters.  When the last animal had sprung over the chasm, Glenn thanked the propitious accident that thus providentially prevented him from being crushed to atoms, and uttered a prayer to Heaven that he might by a like means be rescued from the fiery ordeal that awaited him.  It now occurred to him that the accumulation of weeds and grass in the chasm, which saved them from injury when