The boys gazed awe-struck at this mighty spectacle, drenched by the spray that seemed to fill the vast cavern. As he gazed, a desperate plan took form in Phil’s mind, and he lost no time in communicating it to the others.
He pointed to the rushing river, and started removing his coat and shoes. The others divined his purpose, and with a reckless light in their eyes they followed suit.
They had heard of underground rivers, and knew that they nearly always come out into the open at some point. They were all good swimmers, and preferred to trust to the river rather than waste their strength in aimless gropings through the endless subterranean tunnels. But it required the highest kind of courage to plunge into the black and raging torrent, knowing that the chances were all against them.
Phil was the first to take the plunge, closely followed by the others. The roaring flood caught avidly at them, like some ferocious monster seizing his prey. They were whirled away like chips on the surface of the torrent, caught up in eddies, drawn under the surface, battered and buffeted, but always fighting gamely for life against overwhelming odds. The river flowed deep and strong, and they were carried at tremendous speed for what seemed an infinite lapse of time. In the black darkness, no one knew what had become of the others, but each one struggled valiantly against the mighty torrent that was beating the life from him.
At last, far away, they caught a glimpse of daylight, and the sight put renewed strength into their tired muscles. Buffeted about on the torrent, they shot out from black gloom into the glorious light of the setting sun. By some miracle, they were all close together, and they started then to work across the stream toward the bank. After the river emerged from the mountain, it broadened out and slowed down somewhat, so that it was not long before the three comrades reached the bank, and dragged themselves out onto a gravelly beach.
Chilled to the bone by the icy water, and exhausted by the struggle, they could hardly move at first, but soon their lusty youth asserted itself. Phil was the first to struggle to his feet, pale and dripping, but with a brave attempt at a smile nevertheless.
Dick and Tom sat up, and then got to their feet, and the three friends silently shook hands. Then they set out to locate the aeroplane, as they knew it would soon be dark, and they had no desire to spend the night hungry and in their wet clothing.
But it took them longer to find the Arrow than they had anticipated. The place where the river emerged from the mountain was almost on the opposite side to that where they had left their machine, and it was only after nearly two hours of heartbreaking struggle through dense woods and underbrush that they finally came in sight of the white-winged airship. But almost at the same moment they caught sight of something else that whipped their flagging energies into instant action.
On a slight eminence about a mile distant were gathered a group of horsemen. They had caught sight of the airship, which was a conspicuous mark against the green background. They were pointing and gesticulating, and even as the boys watched them, headed their horses at a gallop in the direction of the airship.
The Radio Boys were several hundred yards from the Arrow at this time, and they fought their way silently and savagely through the dense underbrush. As they neared their machine, they could hear the Mexicans’ horses crashing through the bushes and the cries and oaths of their riders.