Andy jammed the sweep with which he had been steering between his knee and the stake at the rear of the sledge, and put his gun to his shoulder. "Shoot into the nearest bears, boys," he commanded. "You both take that big fellow right ahead. Get him down and I'll try to pepper those on either side." But the bears were all shuffling across the ice to get at the sailing sleds. They were fast bunching immediately in the front of their human enemies. Jack and Mark obeyed the old hunter's order. They poured their fire into the huge, shaggy beast that rose on its hind legs before the sled, and roaring, spread its huge paws abroad ready to seize it and its human burden. Fortunately the wind had suddenly increased as the sleds rounded the wooded point. They were traveling faster. The lead pumped from the rifles of the two boys spattered against the breast of the great grizzly, and stained its coat crimson in great blotches. But he stood, roaring in rage and pain, until the sled was right upon him. Jack and Mark were forward of the sail, which was hoisted amidships. The sled was surrounded by the savage beasts, and when it struck the tottering brute that alone stood in its direct path, there seemed to be at least half a dozen of the bears on either side, rising on their haunches in preparation to strike. The collision almost overbalanced the sled. It certainly overbalanced the bear, that had been hit by eight bullets from the rifles of Jack and Mark. And the huge body, lying right across the path of the sledge, halted it. "Swing your guns, boys!" bawled Andy. "Jack to the left, Mark to the right hand." Our heroes understood this command. They had been in tight places before with the old hunter, and now they partook of his enthusiasm. The rifles spattered the lead among the nearest bears. Some of the creatures fell back wounded. Some were merely enraged the more and, roaring their wrath, continued to advance. Meanwhile the old hunter had seized the steering sweep and endeavored to turn the sled aside. It had rebounded from the heavy carcass of the bear which had dropped upon the ice before it. Now Andy tried to work the sled around this obstruction. The second sled came; on, the professor relieving Roebach at the helm, and the oil man and Washington White pouring in volley after volley at the bears. The black man was a good shot and in the excitement of the battle he forgot to be terrified. His bullets told as well as did those from the rifle of Phineas Roebach. And fortunately the aged scientist brought this second sled safely through the line of bears. The first sled took the brunt of the battle. When that on which the professor sailed was a hundred yards beyond the herd of Kodiaks, he swerved it into the eye of the wind and so brought it to a halt without lowering the blanket that served as a sail. "Come on back and help' em!" cried Phineas Roebach, leaping out upon the ice.