within half an hour the gig had reached the mouth of the cave. as the coxswain had predicted, the seas ran into the lofty entrance. elsewhere the surf fell whitely, but through the arch the waves rolled unbroken into a heavy stillness. only as the boat hovered for a moment at the face of the cliff could the exploring party hear, far within, the hollow boom that told of breakers on a distant, subterranean beach.

"run 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 roared again with the summons. silence, formidable and unbroken, succeeded.

"house to house search is now in order," he said. "must be in here somewhere--unless the seals got him."

cautiously the boat moved forward. once she grazed on a half submerged rock. again a tiny islet loomed before her. scattered bones glistened on the rocky shore, but they were not human relics. occasional beaches tempted a landing, but all of these led back to precipitous cliffs except one, from the side of which opened two small caves. into the first the lantern cast its glare, revealing emptiness, for the arch was wide and the cave shallow. the entrance to the other was so narrow as to send a visitor to his knees. but inside it seemed to open out. moreover, there were fish bones at the entrance. the captain, the surgeon, and congdon, the coxswain, landed. captain parkinson reached the spot first. stooping, he thrust his head in at the orifice. a sharp exclamation broke from him. he rose to his feet, turning a contorted face to the others.

"poisonous," he cried.

"more volcano," said trendon. he bent to the black hole and sniffed cautiously.

"i'll go in, sir," volunteered congdon. "i've had fire-practice."

"my business," said trendon, briefly. "decomposition; unpleasant, but not dangerous."

pushing the lantern before him, he wormed his way until the light was blotted out. presently it shone forth from the funnel, showing that the explorer had reached the inner open space. captain parkinson dropped down and peered in, but the evil odour was too much for him. he retired, gagging and coughing. trendon was gone for what seemed an interminable time. his superior officer fidgeted uneasily. at last he could stand it no longer.

"dr. trendon, are you all right?" he shouted.

"yup," answered a choked voice. "cubbing oud dow."

again the funnel was darkened. a pair of feet appeared; then the surgeon's chunky trunk, his head, and the lantern. once, twice, and thrice he inhaled deeply.

"phew!" he gasped. "thought i was tough, but--phee-ee-ee-ew!"

"did you find--"

"no, sir. not darrow. only a poor devil of a seal that crawled in there to die."

the exploration continued. half a mile, as they estimated, from the open, they reached a narrow beach, shut off by a perpendicular wall of rock. skirting this, they returned on the other side, minutely examining every possible crevice. when they again reached the light of day, they had arrived at the certain conclusion that no living man was within those walls.

"would a corpse rise to the surface soon in waters such as these, dr. trendon?" asked the captain.

"might, sir. might not. no telling that."

the captain ruminated. then he beat his fist on his knee.

"the other cave!"

"what other cave?" asked the surgeon.

"the cave where they killed the seals."

"surely!" exclaimed trendon. "wait, though. didn't slade say it was between here and the point?"

"yes. beyond the small beach."

"no cave there," declared the surgeon positively.

"there must be. congdon, did you see an opening anywhere in the cliff as we came along?"

"no, sir. this is the only one, sir."

"we'll see about that," said the captain, grimly. "head her about. skirt the shore as near the breakers as you safely can."

the gig retraced its journey.

"there's the beach, as slade described it," said captain parkinson, as they came abreast of the little reach of sand.

"and what are those two bird-roosts on it?" asked trendon. "see 'em? dead against that patch of shore-weed."

"bits of wreckage fixed in the sand."

"don't think so, sir. too well matched."

"we have no time to settle the matter now," said the captain impatiently. "we must find that cave, if it is to be found."

hovering just outside the final drag of the surf, under the skilful guidance of congdon, the boat moved slowly along the line of beach to the line of cliff. all was open as the day. the blazing sun picked out each detail of jut and hollow. evidently the poisonous vapours from the volcano had not spread their blight here, for the face of the precipice was bright with many flowers. so close in moved the boat that its occupants could even see butterflies fluttering above the bloom. but that which their eager eyes sought was still denied them. no opening offered in that smiling cliff-side. not by so much as would admit a terrier did the mass of rock and rubble gape.

"and slade described the cave as big enough to ram the _wolverine_ into," muttered trendon.

up to the point of the headland, and back, passed the boat. blank disappointment was the result.

"what is your opinion now, dr. trendon?" asked the captain of the older man.

"don't know, sir," answered the surgeon hopelessly. "looks as if the cave might have been a hallucination."

"i shall have something to say to mr. slade on our return," said the captain crisply. "if the cave was an hallucination, as you suggest, the seal-murder was fiction."

"looks so," agreed the other.

"and the murder of the captain. how about that?"

"and the mutiny of the men," added the surgeon.

"and the killing of the doctor. your patient seems to be a romantic genius."

"and the escape of darrow. hold hard," quoth trendon. "darrow's no romance. nothing fictional about the flag and ledger."

"true enough," said the captain, and fell to consideration.

"anyway," said trendon vigorously, "i'd like to have a look at those bird- roosts. mighty like signposts, to my mind."

"very well," said the captain. "it'll cost us only a wetting. run her in, congdon."

with all the coxswain's skill, and the oarsmen's technique, the passage of the surf was a lively one, and little driblets of water marked the trail of the officers as they shuffled up the beach.

the two slabs stood less than fifty yards beyond high water tide. nearing them, the visitors saw that each marked a mound, but not until they were close up could they read the neat carving on the first. it ran as follows:

_here lies_

solomon anderson

_alias_

handy solomon

_who murdered his employer,

his captain, and his shipmates,

and was found, dead

of his deserts, on these shores,

june 5, 1904.

this slab is erected as a

memento of admiring esteem

by

the last of his victims.

"and you can kiss the

book on that."_

"percy darrow _fecit_," said the surgeon. "you can kiss the book on _that_, too."

"then slade was telling the truth!"

"apparently. seems good corroboration."

the captain turned to the other mound. its slab was carved by the same hand.

_sacred to the memory of an

ensign of the u. s. navy,

whose body, washed upon this

coast, is here buried with all

reverence, by strange hands;

whose soul may god rest.

"the seas shall sing his

requiem." june the sixth,

mxmiv._

"billy edwards," said the captain, very low.

he uncovered. the surgeon did likewise. so, for a space, they stood with bared heads between the twin graves.