Hardly had Jack time to note this, when the light was suddenly blotted out, as if a great curtain had been drawn across the sun. There was a mighty roaring, like that of a thousand huge cataracts in his ears, and he knew that they had entered the water tunnel.
Where would it lead them?
Fortunately, to Jack, fresh as he was, it was not hard to support Ralph, who was almost exhausted, and keep his own head above water at the same time. All that the Western boy now feared was that he would give out before they reached the mouth of the tunnel, or a still more alarming possibility which he hardly dared to dwell on.
What if the tunnel narrowed?
In that case they would be completely submerged, and if the water were enclosed in an iron tube for any great distance, they would inevitably be miserably drowned. The roaring in the tunnel was terrific, but at least it meant one thing, and that was that there was space for sound to reverberate.
On and on they shot, borne like straws on the surface of the mad torrent.
"Does this thing never end, or have they run it clear through to the Pacific?" Jack began to wonder.
It seemed to him they had been traveling for hours. In reality it was only a few minutes.
All at once the boy was hurled against the side of the tunnel, and his feet touched bottom. If it had not been for the velocity of the current, he could have stopped his mad course right there. But the smooth sides of the tube afforded no hand hold, and the rapidity of the stream precluded all idea of attempting to stem the torrent.