"Orders, sir!" he bawled, whipping his mouthpiece aside for the moment. "This here's a fine old mess!" "Must get those gas valves open and the engines started again. Here," Dick gasped in answer. "Make this cylinder fast to my shoulders. It's too loose for my liking. There's a bit of rope yonder. That'll do it. Quick!" He had no breath for more; but Hawkins seemed to see his meaning in an instant, and soon had the cylinder of oxygen more secure on Dick's back. Then, with a dexterity which even this critical situation could not mar, he secured his own cylinder in similar manner. Dick gripped a hammer. Hawkins took a huge spanner. "Now," said our hero. "We must get to the upper deck. Then start in the centre, each going in opposite directions. Force open every other valve. Even if you have to smash them to pieces you must contrive to open them. Come--no time to be lost." His orders were given in short gasping spurts. But Hawkins understood and nodded. Then they clambered over the bodies of their comrades, won their way up the engine ladder, and raced as fast as they could along the gallery. Not that the pace was great, for each step seemed to be an effort. They gained the liftway, and stared upward. "No motor working. Must climb," Dick managed to gasp. "Up we go." He felt as if his heart would burst long before he gained the upper deck. That organ was indeed thudding heavily against his ribs, while the veins in his forehead, on his hands and face, were distended and purple. But there was pluck and determination to drive Mr. Dicky Hamshaw onward, while Hawkins was not the man to be beaten by an officer or to leave one in the lurch. And so, after a struggle which cost them dear, they won their way to the summit of that tiresome and never-ending ladder. A minute later, almost too fatigued to deliver a blow, they attacked the valves affixed to each of the many gas chambers, beginning with those at the centre. "Frozen hard as rocks. Deck covered with frost and ice. The weight'll be an advantage. But how are we to get these valves open?" It was difficult enough under that white covering to detect their presence, though, fortunately for all, both Dick and Hawkins had more than once examined the valves. Now they set to work with hammer and spanner, breaking away the coating of ice, and smashing the firm joint which the intense cold had formed round each seating. It was with a shrill, half-stifled cry of delight that Dick contrived to free the first of the valves. "Wide open. Can smell the gas coming out," he told himself. "That'll fix her. A few more will do the trick. Wish to goodness she'd remain level."