Here was the clue to a melancholy story. Samuel Vernon, under the guidance of Negoro, and taking with him his dog Dingo, had set out on an exploration of a district of Central Africa; he had taken a considerable quantity of money to procure the necessary supplies on the way, and this had excited the cupidity of his guide, who seized the opportunity, whilst they were encamping on the banks of the Congo, to assassinate his employer, and get possession of his property. Negoro, however, had not escaped; he had fallen into the hands of the Portuguese, by whom he was recognized as an agent of the slave-dealer Alvez, and condemned to spend the rest of his days in prison. He contrived after a while to make his escape, and, as has been already mentioned, found his way to New Zealand, whence he had returned by securing an engagement on board the "Pilgrim." Between the time when he was attacked by Negoro and the moment of his death, Vernon had managed to write the few brief lines of which the fragments still survived, and to deposit the document in the box from which the money had been stolen, and by a last effort had traced out his initials in blood upon the naked wood which formed the wall of the hut. For many days Dingo watched beside his master, and throughout that time his eyes were resting so perpetually upon the two crimson letters in front of him, that mere instinct seemed to fasten them indelibly on his memory. Quitting his watch one day, perhaps to pacify his hunger, the dog wandered to the coast, where he was picked up by the captain of the "Waldeck," afterwards to be transferred to the very ship on which his owner's murderer had been engaged as cook.

All throughout this time poor Vernon's bones had been bleaching in the African forest, and the first resolution of Dick and Mrs. Weldon was to give the residue of his remains some semblance of a decent burial. They were just proceeding to their task when Dingo gave a furious growl, and dashed out of the hut; another moment, and a terrible shriek made it evident that he was in conflict with some dread antagonist.

Hercules was quickly in pursuit, and the whole party followed in time to witness the giant hurl himself upon a man with whom already Dingo was in mortal combat.

[Illustration: The dog was griping the man by the throat]

The dog was griping the man by the throat, the man was lifting his cutlass high above the head of the dog.

That man was Negoro. The rascal, on getting his letter at Kazonndé, instead of embarking at once for America, had left his native escort for a while, and returned to the scene of his crime to secure the treasure which he had left buried at a little distance in a spot that he had marked. At this very moment he was in the act of digging up the gold he had concealed; some glistening coins scattered here and there betrayed his purpose; but in the midst of his labours he had been startled by the dashing forward of a dog; another instant, and the dog had fixed itself upon his throat, whilst he, in an agony of desperation, had drawn his cutlass and plunged it deep into the creature's side.

Hercules came up at the very climax of the death-struggle.

"You villain! you accursed villain! I have you now!" he cried, about to seize hold of his victim.

But vengeance was already accomplished. Negoro gave no sign of life; death had overtaken him on the very scene of his guilt. Dingo, too, had received a mortal wound; he dragged himself back to the hut, lay down beside the remains of his master, and expired.

The sad task of burying Vernon's bones, and laying his faithful dog beside them having been accomplished, the whole party was obliged to turn their thoughts to their own safety. Although Negoro was dead, it as very likely that the natives that he had taken with him were at no great distance, and would come to search for him.