The meal brightened Rob up wonderfully. After eating it he sat on the edge of the bunk casting about for something to keep his mind off his troubles, when he suddenly recollected the mysterious cipher found on the _Good Hope_. Reaching into his pocket he pulled it out and began figuring with the stump of a pencil on the back of an old envelope. But ingenious as he was, he found it hard to decipher. He tried half a dozen well-known systems on it and was about to give up in despair when he recalled the "Letter" method of reading cryptic numeral ciphers. This system requires the operator to figure out the recurrence of different numerals and the order in which they appear. Rob noticed that the number 5 occurred most frequently. Now E is the most used letter in any bit of English writing, so the lad set down 5 as answering for E. After this he figured industriously till he had managed to make something like sense out of the first paragraph of the old writing. It would be wearisome to take the matter step by step in all its details. Suffice it to say, therefore, that Rob found that he had hit on a correct system and at the end of two hours had the following message before him. "It is buried twenty-four paces from dead cypress and to the west. The island lies in long. 80 degrees 50 minutes and lat. 33 degrees 24 minutes. To whoever finds this and reads it, I will the ivory. Death is close to me now. Good bye to all." When his task had been completed, Rob sat gazing at the paper before him. Unquestionably it gave the location of the dead whaler's cache. For an instant the boy thought, with a thrill, that he was within reach of a fortune. But the next moment he recalled where he was, which, in the interest of his task, he had forgotten. Then, too, he remembered that the dead man's two companions who marooned him on his own ship had probably carried out their intention of returning and carrying off the precious hoard. "So that's all of that," mused the boy, "but just the same, if I ever get out of this scrape, I mean to hunt up that island and see if I can locate the fate of those mammoth tusks." All day the boat moved swiftly along, and it was not till the following morning that anchor was dropped, as Rob knew by feeling the motion of the craft stopped, and by hearing the rattle of the anchor chain. "I wonder what is going to happen to me now?" he mused. He had not long to wait. "Come out on deck and help us row the dinghy ashore," Gyp muttered as he unlocked the door. Heartily glad to get out of his cramped quarters, Rob obeyed. Coming on deck he found Berghoff and Mike already there. The former had a formidable-looking revolver strapped on him. The boat was lying off a small, sandy island, isolated from the others, in one of the groups that are common on that part of the coast.