Some little time before evening set in they were ready to fill up the last opening. The rest of the dam was finished, every little crack and cranny that they could find had been filled up with a turf which was well pressed home, they had strengthened it here and there, and, so far, the work held good. The moment to try its firmness would be when the last opening was closed and the dam would have to resist the full weight of the water. The boys had collected a great pile of rocks and stones and large and small sods of turf and earth by the side of the narrow opening, through which the whole force of the stream now rushed. They stood with a huge lump of stone hanging just over the opening.
"Are you ready, Geordie?"
"Yes."
"Let go."
With a mighty splash the stone fell just where it was wanted, and without waiting a second both boys began piling on and round it lumps of rock and turf and large rounded pebbles. It was an exciting moment, for the flow of the waterfall had entirely ceased, and the strange silence was fraught with a significance in their ears that was far greater and more imposing to them than was the loud roar to which they were accustomed. Wildly they continued piling on turf, and then lumps of rock to fix it, till the opening was filled up to the level of the rest of the dam.
It was an anxious time for them as they saw the water rising, rising rapidly, towards the top of their little embankment. In one or two places it began to creep in a little wriggling streak over the topmost layer of turf and rock; but it was never allowed to flow, for one or other of the boys rushed into the water, that now reached half-way up their thighs, and added more material and jammed it firmly down. Would the dam hold out? Could it withstand the enormous pressure of the water? Yes, yes. Hurrah! See there, a silver streak is flowing into the old disused channel which the boys have so carefully cleared for it. Every moment, every second it grows broader, deeper, and in a short time a splash is heard where the new waterfall is beginning to pour itself over the cliff, not into the pool but on to the dry hot rocks of the gully some little way to one side of the basin. Every moment this noise grows louder and louder, till in a very few seconds the roar of this new cascade is as deep and thundering as the silenced voice of its dead brother, and the water is pouring down the gully along a fresh course till it joins the stream again just at the bend of the ravine.
It is a proud moment for those young engineers, and they feel that glow of honest satisfaction in successful work which is worth so much more than other peoples' praises, that are so often given for what one does not value.
"Well, I suppose we have done half the work," said Alec, as they sat by the fire in front of the humpie when they had finished their supper.
"Yes, but it is the harder half that is left to be done. It will take a long time to drill a hole into the rock."
"I don't know how we are going to do it, for we haven't a chisel or a bit of steel that we can use for one."