"Even that is too soon for safety," said the Doctor back over his shoulder, for already he had started downward.
It was nearly twelve o'clock when they stopped again for rest. At this time the valley appeared about seven or eight thousand feet deep: they estimated themselves to be slightly more than half-way down. From eleven until twelve they had momentarily expected some disturbing phenomena attendant upon the removal of the ring by the Banker from the clubroom to its place in the Museum. But nothing unusual had occurred.
"He probably decided to leave it alone for a while," commented the Big Business Man, as they were discussing the matter. "Glad he showed that much sense."
"It would not bother us much now," the Doctor replied. "We're too far down. See how the light is changing."
The sky showed now only as a narrow ribbon of blue between the edges of the cañon's walls. The sun was behind the wall down which they were climbing, out of sight, and throwing their side of the valley into shadow. And already they could begin to see a dim phosphorescence glowing from the rocks near at hand.
The Very Young Man, sitting beside the Doctor, suddenly gripped his friend by the arm. "A bird," he said, pointing down the valley. "See it there?"
From far off they could see a bird coming up the center of the valley at a height apparently almost level with their own position, and flying towards them. They watched it in silence as it rapidly approached.
"Great Scott, it's big!" muttered the Big Business Man in an undertone.
As the bird came closer they saw it was fully fifty feet across the wings. It was flying straight down the valley at tremendous speed. When it was nearly opposite them they heard a familiar "cheep, cheep," come echoing across the valley.
"The sparrow," whispered the Very Young Man. "Oh, my gosh, look how big it is!"