A suppressed cheer broke from some of the bystanders, who had no cause to love Macguire. He scowled fiercely at them as he climbed back to his seat.
"I'll get even with you, you young thief, when there are no interferin' Wardens about," he cried as he drove away, glaring with impotent rage at the object of his exceeding wrath.
The Shadow smilingly waved him a polite adieu.
CHAPTER VII Bob's Triumph
It was three days after the Shadow's departure. The sun was shining fiercely on Golden Flat, and its scintillating rays reflected from the white mullock heaps at the various workings caused the eyes of the miners when they came to the surface to quiver and close painfully. The air was filled with dancing sand particles, and they shimmered kaleidoscope-like in the intense heat haze which rose and fell on the surface of the land like the waters of a boundless ethereal sea. The regular thud, thud of picks resounded loudly from the end of the lead where Nuggety Dick and his brawny compatriots were doggedly digging out the golden gravel, and away at the other end of the field Macguire's satellites made noisy din as they busied themselves sinking several shafts over the supposed trend of the mysterious channel.
The weather had been excessively hot since the Shadow left, and this fact had done much to restore the spirits of the gang, for, judging from their own feelings, they considered that the energy of Mackay's messenger would be spent long before he could hope to reach the township. At the Golden Promise the windlass was deserted, and the red symbol hung limp overhead. But it was not lack of energy that had occasioned this apparent lapse of duty. Mackay and Jack had been in the tent all morning watching Bob's final experiments with the refractory clay formation which were to decide whether or no the great bulk of the Flat's treasure could be saved to them. Bob's head was now quite better, but prolonged study in a clime which is not adapted for acute mental effort had made his young face appear drawn and haggard, yet his eyes shone with the light of enthusiasm as he busied himself with his rather crude appliances and set them in order for a last conclusive test. Mackay had hastily constructed a small vat for him, made from the hardest wood to be found in the bush, with an overflow tap some halfway up its height. This the young chemist now quarter filled with the crushed compound to be tested, and made up the level with water, to which he afterwards added some salt.
"It will ensure its conductivity," he explained; but neither Mackay nor Jack were much enlightened, so they held their peace. Next a rubber tube, with an oddly-conceived wooden shield on its exposed extremity was thrust into the receptacle, then a small bottle containing some liquid which bubbled and effervesced alarmingly, was brought forward, and its loose nozzle connected to the free end of the tube.
"A simple method of generating hydrogen," said Bob dreamily, "just iron pebbles and very dilute sulphuric acid." Mackay ventured a non-committal grunt, but Jack's face now showed keen appreciation. Lastly the two wires of a very small electric battery—Bob's own manufacture—were connected to corresponding metallic sheets lining the opposing ends of the vat. "That is merely as an added assistance to help the decomposing of the stuff into its elements," muttered Bob; then he fixed the nozzle of the hydrogen generator tightly and stepped back.