Bob looked thoughtful. "I'll fix up a dummy battery and an extra generator for their special benefit," he suggested.
"A good idea, my lad, and I'll see that Emu Bill and the boys are close handy in case o' accident. Jack can stand by an' help you. I'll attend to the dumping o' the ore, and the overflow arrangements, an' flatten out any man wha's troubled wi' an excess o' inquisitiveness."
"An' I," spoke the Shadow, "I reckons I'll keep my blinkers open for any suspicious-lookin' cusses, an'—— Howlin' centipedes! there's one now! Blow me if it ain't that pestiferous son o' a gun back again."
They looked and saw Macguire in close conversation with a short, nattily dressed man of about middle age. Then the crowd closed up again, and hid the plotters—for such they undoubtedly were—from view.
The trial had been arranged to take place at seven o'clock in the evening, chiefly because the great heat of the sun at an earlier period would have been most trying for the spectators and experimentalists alike, but Mackay had also the idea that at such a time the working arrangements would be less visible to the onlookers, and though he did not then think that any danger was likely to arise in this respect, he now congratulated himself on his cautionary scruples. Indeed, if the three partners could have foreseen that so many outsiders were to be present, no public exhibition of the process would have been promised. But it was too late now to alter their plans; the test must go on, come what may; and though Bob was confident of success, his mind was somewhat troubled by the appearance on the scene of so many strangers, and the arrival of Macguire added much to his apprehensions. An hour before the stated time all was in readiness for the ordeal. The gas generators and batteries were placed behind the vat and loosely covered by some old ore-bags, then the enclosing canvas screen was pulled away. A number of oil lamps hung around gave ample light, while at the same time their reflectors were so arranged as to cast a deep shadow over the lowly placed chemical plant. Every safeguard against prying eyes had been employed before the curtain was taken down, and now the interested spectators gazed curiously on the huge wooden structure which revealed itself to them. Ten tons of the ore to be treated rested on a platform built at the top of the vat; it was all neatly arranged in bags, each of ten claims having provided a ton, while an extra half-dozen tons taken from the Golden Promise lay conveniently near at hand.
Bob stepped with apparent carelessness to the concealed batteries and made the connections secure; Mackay mounted the platform to tip in the ore, and Jack casually stood guard in front of the hidden plant. Then Macguire's harsh voice cackled out in protest—
"We want to see the inside o' the concern before you start; you may have salted it for all we knows."
Bob's lips compressed tightly at the words. "I am not a professional conjurer," he said with dignity, "and I have nothing to gain one way or another from any of you. If you represent the feelings of the miners here, I shall go no further."
A cry of dissent at once arose, and Macguire's safety seemed for the moment imperilled; but in the midst of the uproar, Bob calmly unscrewed the bottom from the vat and pulled it forth for inspection, and he noted that those who came forward at his request were without exception the men whose good intentions Mackay had so much doubted. The interruption did not delay matters for more than a minute or so, then Mackay began to load the vat, and in a short space the onlookers were listening to its turbulent outbursts in amazed silence. At this stage, Macguire, accompanied by the man he had been seen with earlier in the evening, pushed his way forward until he was almost touching the foaming caldron. But they did not escape the lynx eyes of Emu Bill and the Shadow, whose stern grips were on their shoulders at once.
"Let them stay, Bill, if they want," said Bob, quietly.