As they again approached Mount Harris on the Macquarie, where they expected to find a relief party with fresh supplies, fears began to be entertained regarding the safety of those who might be awaiting them at the depôt. The reed beds were in flames in all parts, and the few natives they met displayed a guilty timidity, and one was observed with a jacket in his possession. Their fears were, however, fortunately vain, the natives had made one attempt to surprise the camp, but it had been frustrated, and the relief party had now been some three weeks awaiting the return of the explorers.
Sturt rested for some days, during which time Hume made a short western trip.. to the south of the marsh land. He reported that for thirty miles the country was superior to anything they had yet seen, and exceedingly well watered; beyond that distance the plains and brush of the remote interior again resumed their sway.
On the 7th March the party struck camp and made for the Castlereagh, the relief going back to Bathurst. On the 10th they reached the Castlereagh, and found it apparently without a drop of water in its bed. From here downwards the old harassing hunt for water commenced once more, and as they descended the river they were further puzzled by the intricate windings of its course and the number of channels that intersected the depressed country they were travelling through. On the 29th they again struck the Darling, ninety miles above the spot where they had discovered it:
"This singular river still preserved its character so strikingly that it was impossible not to have recognised it in a moment. The same steep banks and lofty timber, the same deep reaches, alive with fish, were here visible as when we left it. A hope naturally arose to our minds, that if it was unchanged in other respects, it might have lost the saltness that rendered its waters unfit for use; but in this we were disappointed-even its waters continued the same."
Fortunately the adventurers were not this time in such unhappy straits for water as before, so that the disappointment was less intense. Knowing what they might expect if they followed the Darling down south, the party at once halted. It was evident that to the east and north-east, the rigorous drought had put its mark on the land, from the fact that large bodies of natives driven in from that direction were congregated round the few permanent waters left. A reconnoitring expedition across the Darling to the N.W. was accordingly determined on, to see if any advance into the interior was possible, and after a camp had been formed Sturt and Hume started on the quest. No encouragement to proceed resulted. By four p.m. they found themselves on a plain that stretched far away and bounded the horizon.
"It was dismally brown, a few trees only served to mark the distance. Up one of the highest I sent Hopkins on, who reported that he could not see the end of it, and that all around looked blank and desolate. It is a singular fact that during the whole day we had not seen a drop of water or a blade of grass.
"To have stopped where we were would, therefore, have been impossible; to have advanced would probably have been ruin. Had there been one favourable circumstance to have encouraged me with the hope of success I would have proceeded. Had we picked up a stone, as indicating our approach to high land, I would have gone on; or had there been a break in the country, or even a change in the vegetation; but we had left all traces of the natives behind us, and this seemed a desert they never entered—that not even a bird inhabited. I could not encourage a hope of success, and therefore gave up the point, not from want of means, but a conviction of the inutility of any further efforts. If there is any blame to be attached to the measure it is I who am in fault; but none who had not like me traversed the interior at such a season would believe the state of the country over which I had wandered. During the short interval I had been out, I had seen rivers cease to flow before me and sheets of water disappear, and had it not been for a merciful Providence should, ere reaching the Darling, have been overwhelmed by misfortune.
"I am giving no false picture of the reality. So long had the drought continued that the vegetable kingdom was almost annihilated, and minor vegetation had disappeared."
Once more the order to retreat from the inhospitable Darling was given, and the weary march home recommenced. On their way they traced and followed a defined channel, or depression, formerly crossed by Hume, and ascertained it to be the outflow of the Macquarie Marshes. On the 7th of April, 1829, they reached Mount Harris.
The mystery of the Macquarie was now, to a certain extent, cleared up, but there still remained another riddle to solve in the course and outlet of the Darling. Sturt, the discoverer of this river, was destined to find the answer to this problem as well.