Bob flushed. "I forgot," said he, "that there was any reason for keeping it secret."
The elder man laughed grimly. "My laddie," he began, with grave earnestness, "are ye no' aware that there should be a fortune in this for you. There may be tens o' thousands o' tons o' the stuff in this Flat, and allowin' ye made a charge of, say, £2 a ton—which is little more than battery price—don't you see what a tremendous profit would be made? You canna patent a discovery, Bob; and your only safety is in keeping it secret. The great danger lies in the simplicity o' the process. We must be vera careful, my lad, vera careful indeed."
"But did I really tell them everything?" said Bob, abashed; for in truth he had forgotten the presence of his audience, so wrapped up had he been in the interest of his subject.
"Oh yes, you telt them richt enough; but you clothed your observations in such elegant scientific language that I'm sure not a man among them kent what ye were talkin' aboot."
"You did give them a pretty bad time," grinned Jack. "It was a treat to see them wrestling with hydrocarbonaceous compounds, and electrolytical principles; but didn't they howl when they saw the gold!"
"I reckon that talks every time," said Mackay.
No time was now lost in erecting the vat and other appliances necessary for the bulk treatment of the strange deposit. Wood was obtained from the saw mill, and Mackay, assisted by Jack and the Shadow, started to build the giant trough for the retention of the ore. Only half-sawn, rounded timber was used, for that alone could support the strain that must finally be put upon the structure; a movable bottom was also fixed to allow of the ultimate residue being drawn off easily, and the whole was mounted on a stout standard of logs raised about five feet from the ground.
As may be imagined, a constant stream of visitors came to view the peculiar erection before it was nearly half completed; but when Bob's important chemical and electrical arrangements were ready to be fitted, Mackay, much to the disgust of the beholders, screened the entire plant from their gaze by building a tall canvas wall around it. By the end of the week everything was in readiness for the trial, which was given out to take place in the evening, and a vast assembly gathered to witness the inauguration of what was now known as the "Hope of Golden Flat." So speedily had the news travelled concerning it, and so vastly interested had even the outside world become in the problematical future of the Flat's odd formation, that by Saturday morning quite a number of men from Kalgoorlie and far outlying townships made their appearance, and a steady stream of buggies and horsemen poured in along the track all day. Indeed, it seemed as if a fresh rush had set in, so keen was the excitement.
But Mackay was ill at ease. Among the throng of new-comers he had recognized several of the cleverest mining engineers in the State, and none of them had reputations for being over-scrupulous.
"There'll be a careful eye kept on us to-night, Bob," said he. "An' I'm just a wee bit dubious o' the intentions o' some o' our visitors."