“If we want to get up the wall we won’t want any scaling ladders,” remarked Tom grimly.  “Oh, if only we knew that Dick and Uncle Randolph were safe!”

“I’m going to find out pretty soon,” replied Sam.  “I’ll tell you what I think.  I think they are being held for ransom.”

“I was thinking of that, too.  But I didn’t dream of such a thing being done down here although, I know it is done further north in Africa among the Moors and Algerians.”

Cujo now went off on another scout and did not return until the sun was setting.  Again he was full of smiles.

“I can show you a way up de rocks,” he said.  “We can get to the walls of um fort, as you call um, without being seen.”

Soon night was upon them, for in the tropics there is rarely any twilight.  Tom now declared himself able to walk once more, and they moved off silently, like so many shadows, beside the swamp and then over a fallen palm to where a series of rocks, led up to the cliff proper.

“Sh-ah!” came presently from Cujo.  “Man ahead!”

They came to a halt, and through the gloom saw a solitary figure sitting on a rock.  The sentinel held a gun over his knees and was smoking a cigarette.

“If he sees us he will give the alarm,” whispered Tom.  “Can’t we capture him without making a noise?”

“Dat’s de talk,” returned Aleck.  “Cujo, let us dun try dat trick.”

Cujo nodded.  “Urn boys stay here,” he said.  “Cujo fix dat feller!”

And off he crawled through the wet grass, taking a circuitous route which brought him up on the sentinel’s left.

Presently the sentinel started to rise.  As he did so Cujo leaped from the grass and threw him to the earth.  Then a long knife flashed in the air.  “No speak, or um diet” came softly; but, the Frenchman realized that the African meant what he said.

“I will be silent!” he growled, in the language of the African.  “Don’t —­ don’t choke me.”

Cujo let out a low whistle, which the others rightly guessed was a signal for them to come up.  Finding himself surrounded, the Frenchman gave up his gun and other weapons without a struggle.  He could talk no English, so what followed had to be translated by Cujo.

“Yes, de man an’ boy are dare,” explained Cujo, pointing to the fort.  “Da chained up, so dis rascal say.  De captain ob de band want heap money to let um go.”

“Ask him how many of the band there are,” asked Sam.

But at this question the Frenchman shook his head.  Either he did not know or would not tell.

After a consultation the rascal was made to march back to safer ground.  Then he was strapped to a tree and gagged.  The straps were not fastened very tightly, so that the man was sure to gain his liberty sooner or later.  “If we didn’t come back and he was too tight he might starve to death,” said Tom.

“Not but wot he deserves to starve,” said Aleck, with a scowl at the crestfallen prisoner.