He did not dare to look down into the awful void beneath him—vast and empty as eternity itself. Keeping his eyes steadily fixed on the bulging bag, Nat climbed by sheer force of will power till he was up to the network that encased the bag.
Right here began the most difficult and terrifying part of his task. Hanging desperately above the immensity beneath him, he had to make his way to the upper part of the bag. He did not dare to think of what he was doing. The very notion of it made him feel sick and dizzy. The lad just climbed, fixing his mind on the thought of reaching and opening the valve.
Somehow—to this day Nat couldn’t tell you how—he clambered round under the bulge of the bag and began the easier task of making his way up the tightly rounded sides to the top of the great cylindrical gas container. As the professor had surmised, ice had formed on the outside of the bag, and made Nat’s endeavor ten times more hazardous and difficult. This ice had clogged the valve ropes, and Nat saw that the only thing to do was, as he had made up his mind, to climb on till he reached the top of the bag.
The possibilities of a slip were awful, and Nat no more dared think about them than he had about the chances of his slipping when he was hanging between earth and sky under the lower part of the bag. He resolutely dismissed them from his mind.
But the physical difficulties of the lad’s self-imposed task were almost overwhelming. There was a sharp pain in his chest, and his limbs felt as if they had leaden weights attached to them. Suddenly a warm stream of something Nat knew to be blood, gushed from his nose; but still he worked his way upward, climbing amidst the network meshes like a sailor on ratlines.
Once or twice he was compelled to pause from sheer exhaustion, and, clinging on with might and main, to spread himself flat on the surface of the gas bag to rest.
If Nat had not been a clean-lived lad all his life, and had not been a hater of smoking and bad company, he would never have been able to endure this ordeal; but somehow, his young vitality won out, and at last he could reach out a hand and touch the valve.
Bracing himself against the rigging, he tugged with all his might. But the condensed moisture had formed ice on the valve, and it stuck.
Nat felt a childish rage take possession of him. Raising his fists, he beat and tore at the valve, while tears of physical weakness and exhaustion streamed down his cheeks.