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 canon'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!"

In another moment it had passed them; they watched in silence until it
disappeared in the distance.

"Well," said the Very Young Man, "if that had ever seen us----" He drew
a long breath, leaving the rest to the imagination of his hearers.

"What a wonderful thing!" said the Big Business Man, with a note of awe
in his voice. "Just think--that sparrow when we last saw it was
infinitesimally small."

The Doctor laughed. "It's far smaller now than it was then," he said.
"Only since we last saw it we have changed size to a much greater extent
than it has."

"Foolish of us to have sent it in here," remarked the Big Business Man
casually. "Suppose that----" He stopped abruptly.

The Very Young Man started hastily to