"Why then," returned Bill, "ain't it more likely that Bentley's time was wrong? If he came in from the west across the whole darned stretch o' sand-ridges, I reckon he would bust things up a bit."
Bob was startled into fresh energy. "Of course, you're right, Bill!" he cried excitedly. "I've been so anxiously looking for a possible error in my own instrument, I never thought of it occurring with Bentley's. I believe you've hit the solution of the whole difficulty. We'll find Fortunate Spring due east of us in that case, for his latitude would be sure to be right."
"We'll get under way at oncet then," grunted Never Never Dave. "We're bound to meet Mackay comin' back."
At once Jack rushed to Misery's head, and the others hastened to their posts. Bob picked up the sextant and chronometer, and with a surging hope in his heart led the way in the direction that Mackay had taken. Slowly, slowly, they broke through the scrub, Misery's bell sending out its melancholy note, and shattering the oppressive stillness which had prevailed but a few minutes before. Onward they went and onward, and yet no sign of Mackay, and no sign of a spring to gladden their weary eyes. About two miles had been traversed, and the spirits of the forlorn party were drooping fast, when from the bush but a few hundred yards ahead a revolver shot boomed out loudly. With one accord the camels stopped dead. They seemed to realize that something was about to happen. Again came the sonorous echoes of an exploding cartridge, and a hoarse cheer burst from the eagerly listening quartet.
"Mackay has found it! Hurrah! Hurrah!" roared the Shadow, and with renewed effort a path was forced on towards the origin of the welcome sound. Five minutes more and they broke into a rough clearing in the bush in the centre of which a tall lime tree reared high above its dwarfed surroundings; and seated by the tree gazing at some rude markings that showed faintly on the gaunt white trunk, was Mackay. At his feet, sunk among the spreading roots, and half hidden by enclustering grassy growths, gleamed the water of the spring. Bob gave a gasp of relief and thankfulness. Emu Bill and Never Never Dave calmly began to unload the camels, the Shadow after vainly trying to find his speech, mechanically pulled out his musical instrument, and sought to indicate his joy thereon.
Then Mackay arose to his feet, "Dinna desecrate the place, Shadow," said he, in gentle reproach. "Remember this is a monument to the dead."
He motioned Bob and Jack to come forward and view the mossy inscription on the tree, and silently they obeyed his summons. Deep graven in the wood was the legend: "Fortunate Spring, 1898. Bentley's Expedition. Lat. 28° 17´ 5´´, long. 125° 19´ 6´´ (Dead Reck.) Course E." Then followed a list of the initials of the party headed by those of Mackay: "J. M."
By this time Emu Bill, Never Never Dave, and the Shadow had also gathered round to view the symbols left by Mackay's old leader, and as each man traced out the lettering for himself, he doffed his tattered hat reverently.
"Ay, boys," spoke Mackay, breaking the solemn hush that reigned, "it was a fortunate spring for us then, and it's a fortunate spring for this expedition now. But how did you manage to come straight for it, Bob? It took me a good time zig-zagging through the bush before I sighted the tree."
In a few words the young navigator explained the cause of their coming, then he pointed to the inscription "Dead Reck." "That shows that Bentley did not think his readings altogether accurate," he said gravely, "and he meant it as a warning to others, though why he didn't put it on his chart is strange to me."