by the arms or to
leap a wicked-looking crevice, the four took their way up the black
side of the rock. Birds of the cliffs, disturbed from long rest,
wheeled and screamed about them, almost brushing their faces with
long, fearless wings. There was an occasional shelf where, with
backs against the wall spotted with crystals of feldspar, they
waited to breathe, hardly looking down from the dizzy ledge. Great
slabs of obsidian were piled about them between stretches of
calcareous stone, and the soil which was like beds of old lava
covered by thin layers of limestone, was everywhere pierced by sharp
shoulders of stone lying in savage disarray. Gradually rock-slides
and rock-edges yielded a less insecure footing on the upper reaches,
but the chasms widened and water dripping from lateral crevasses
made the vague trail slippery and the occasional earth sodden and
treacherous. For a quarter of a mile their way lay over a kind of
porous gravel into which their feet sank, and beyond at the summit
of a ridge Jarvo halted and threw back to them a summary warning to
prepare for "a long leap." A sharp angle of rock, jutting out, had
been split down the middle by some ancient force--very likely a
Paleozoic butterfly had brushed it with its wing--and the edges had
been worn away in a treacherous slope to the very lip of the
crumbling promontory. From this edge to the edge of the opposite
abutment there was a gap of wicked width, and between was a sheer
drop into space wherefrom rose the sound of tumbling waters. When
Jarvo had taken the leap, easily and gracefully, alighting on the
other side like the greyhound that he resembled, and the others,
following, had cleared the edge by as safe a margin as if the abyss
were a minor field-day event, St. George and Amory looked back with
sudden wonder over the path by which they had come.

"I feel as if I weighed about ninety pounds," said St. George; "am I
fading away or anything?"

Amory stood still.

"I was thinking the same thing," he said. "By Jove--do you
suppose--what if Little Cawthorne hit the other end of the
nail, as usual? Suppose the specific gravity--suppose there is
something--suppose it doesn't hold good in this dimension that
a body--by Jove," said Amory, "wouldn't that be the deuce?"

St. George looked at Jarvo, bounding up the stony way as easily as
if he were bounding down.

"Ah well now," he said, "you know on the moon an ordinary man would
weigh only twenty-six