un her in easy," came the captain's order. "Keep a sharp lookout for
hidden rocks."

To the whispering plash of the oars they moved from sunlight into
twilight, from twilight into darkness. Of a sudden the oars jerked
convulsively. A great roar had broken upon the ears of the sailors; the
invisible roof above them, the water heaving beneath them, the walls that
hemmed them in, called, with a multiplication of resonance, upon the name
of Darrow. The boat quivered with the start of its occupants. Then one or
two laughed weakly as they realised that what they had heard was no
supernatural voice. It was the captain hailing for the marooned man.

No vocal answer came. But an indeterminable space away they could hear a
low splash followed by a second and a third. Something coughed weakly in
front and to the right. Trendon's hand went to his revolver. The men sat,
stiffened. One of them swore, in a whisper, and the oath came back upon
them, echoing the name of the Saviour in hideous sibilance.

"Silence in the boat," said the captain, in such buoyant tones that the
men braced themselves against the expected peril.

"Light the lantern and pass it to me," came the order. "Keep below the
gunwale, men."

As the match spluttered: "Do you see something, a few rods to port?" asked
the captain in Trendon's ear.

"Pair of green lights," said Trendon. "Eyes. _Seals!_"

"_Seals! Seals! Seals_!" shouted the walls, for the surgeon had suddenly
released his voice. And as the mockery boomed, the green lights
disappeared and there was more splashing from the distance. The crew sat
up again.

The lantern spread its radiance. It was reflected from battlements of
fairy beauty. Everywhere the walls were set, as with gems, in broad wales
of varied and vivid hues. Dazzled at first, the explorers soon were able
to discern the general nature of the subterranean world which they had
entered. In most places the walls rose sheer and unscaleable from the
water. In others, turretted rocks thrust their gleaming crags upward. Over
to starboard a little beach shone with Quaker greyness in that spectacular
display. The end of the cavern was still beyond the area of light.

"Must have been a swimmer to get in here," commented Trendon, glancing at
the walls.

"Unless he had a boat," said the captain. "But why doesn't he answer?"

"Better try again. No telling how much more there is of this."

The surgeon raised his ponderous bellow, and the cave ro