At once a gurgling boiling sound arose from the vat, and its contents swelled up in bubbling circles of slime and soapy ooze. Mackay, obeying a motion from Bob, hastily pulled out the overflow tap, and so caused the more solid matter within to subside. Again Bob loaded the vat, and again Mackay allowed the foaming mass to overflow, and never a word was spoken. The operation was repeated until fully a hundredweight of the refractory substance had been utilized, and by this time the floor of the tent was aswim with the dense oily scum let loose.
"That should be enough to calculate on," said Bob. "And now comes the crucial point." He undid all connections and handed the muddy box to Mackay, who took it silently, and emptied the coarse sandy residue into an awaiting gold-pan.
"It's lost its puggy nature, anyway," he commented, pouring on it some water from a kerosene tin. He gave the pan a rapid swirl, then an oblique turn, and gasped. The bottom of the basin was literally covered with a thin film of the finest imaginable golden grains, which blazed and sparkled in the penetrating sunlight!
Bob looked and heaved a sigh of profound thankfulness. Jack looked, and celebrated his joy by whooping like a red Indian. Mackay looked and looked, indeed, he did not once take his eyes off the dazzling spectacle. Bob guessed his fears, and at once dispersed them.
"It's the genuine article this time," he said with assurance. "If it was going to melt away it would have done so in the acid solution; but the fact is it has just been set free from the solution, and so is now as stable and tangible as the sands of the desert."
The rough, horny handed pioneer set the pan down on the floor, and wiped the beaded perspiration from his forehead, then he reached out his great fist and took Bob's hand in a fervent grasp.
"It's no' often I have to acknowledge a better man than mysel'," he said grimly; "but I must admit you've knocked the wind clean out o' me wi' this grand process o' yours. Why, my laddie, it means fortune for you in the years to come, an ever growin' fortune, for ye can charge what ye like for your discovery. An' you little mair than a youngster, too! Man, Bob, you've got a held that any professor might well envy."
Bob laughed right heartily as he returned the elder man's grip. The tension on his nerves had gone, and he felt almost constrained, like Jack, to shout in his gladness.
"If it means fortune, I shall refuse to take more than my third of it," he said, with grave emphasis. "This is a partnership affair. I'd rather break the whole concern up now than make a halfpenny that you two didn't share." Then he gave utterance to a firm, fixed belief, which had done much to sustain him during his intricate studies of the deceptive formation. "As for my youth," he continued, with a smile, and addressing himself more directly to Mackay, "I won't allow that that should entitle me to any credit, for the same brain is with us always, and, surely, when it is young, and fully developed, it should be able to grasp and evolve theories which, when older, it would hesitate to accept. The beaten track is so hard to forsake when one grows old in text-book experience. If the ordinary science professor came along here now and examined my theories concerning this stuff and its treatment, without being shown their proof in practice, he would call them absurd and irrational. And why? Because I have gone wide of all precedent and text-book knowledge, and treated the compound for gold in an unstable state, and in that unstable state it is not supposed to exist." The young man spoke clearly and logically, yet with an unusual twinkle in his keen blue eyes.
When he had finished, Mackay ventured a word of admonition.