Then Jack was silent, marvelling greatly that in his earlier youth at school he had learned so little concerning the vast sandy wastes of Australia. Soon, as they kept on their altered course, the retarding undulations began to grow less and less high, and by late afternoon they had merged into the monotonous plains, now welcome indeed to the travellers after their encounter with the formidable sand-ridges. But their progress that day had barely totalled ten miles, and the camels were well-nigh exhausted after their extreme exertions. The poor brutes had had a severe experience from the beginning, and the rough usage was telling heavily upon their strength. That night they could scarcely muster up sufficient spirit to chew their usual meal of saltbush tips, and, after a few weak efforts, Remorse and Repentance lay down in the sand, while Misery and Fireworks gazed at the little group around the camp-fire with mute, appealing eyes.
"I hope we don't have any trouble finding that spring," said Mackay, anxiously, and instinctively they all turned to Bob with a questioning look. The young navigator winced as he took out his notebook and hurriedly checked his previous calculations.
"We were in latitude 28° 24´ 7´´ at noon to-day," he said quietly; "that should make us about seven miles only from the location of Fortunate Spring, allowing we made five miles since lunch."
"But the longitude, Bob?" asked Mackay. "How do we stand for that?"
Bob again examined his log-book. "I have it marked at 125° 11´ 17´´," he answered, "but we came a good bit easterly since that. I'll try it again in the morning, though I think we're almost on the correct line now, and should hit the Spring by going due north."
He handed the book to Mackay, who glanced at the figures and mentally checked the simpler calculations, but he did not ask for Bob's table of logarithms, and the young man felt satisfied. Bob, indeed, was sure of his positions; they had been worked out with painful exactitude, but he could not help feeling anxious about the morrow. The country in the vicinity seemed so utterly arid and barren. Could the original figures he received be correct? Might not possibly some mistake have crept into Bentley's estimates? He shuddered at the thought, then was immediately sorry for the passing doubt. Who was he who dared question the accuracy of an old and tried explorer's chart? Yet Bob went to sleep that night feeling vaguely uneasy, and by early sunrise he was up taking altitudes, Jack and the Shadow attending him to mark the time of his observations. It was nearly nine o'clock before they were ready to move out that morning; the camels had for a long time refused to be loaded, and when loaded they could not be prevailed upon to arise to their feet, until forced to do so by the necessarily cruel expedient of lighting fires under their noses.
"That's nothing, Jack," Mackay said with a laugh, for he had noticed the look of pain on the boy's face. "They get up long before they're hurt; their hide is like leather, you know, and camels are vera often stubborn and annoying when there's really no occasion for it."
But he knew well that the poor animals were not refractory without reason on this morning, though he endeavoured to make light of the fact. Wearily the heavily laden beasts trudged along, and when the first hour passed, and the sand showed signs of hardening, the Shadow made a valiant effort to infuse life into their hulking movements by blowing at his long-unused mouth-organ vociferously, and making the air resound with discordant notes, for his cracked lips could ill glide along the reeds with any degree of certainty. Bob, who was striding along well in advance, smiled as he heard the concert thus let loose, and he smiled the more when the dismal voices of Emu Bill and Never Never Dave were added to the chorus; and, looking back, he observed these two worthies prancing on with martial steps, though certainly not with martial grace, for their bodies were bent as they pulled their reluctant charges onwards, and their feet, notwithstanding their jaunty uplifting, went down almost in the same place. And Mackay, looking back at the perspiring musician, nodded encouragingly, much to that alert youth's amazement, for he had expected but a rude check as a reward for his labours. Not only did he thus ostensibly appreciate the lively music, but he joined in with his comrades lustily in their vocal exercises; and in this way the labouring train progressed, and almost unnoticeably a thin, straggling array of mallee and mulga shrubs began to dot the hardening sand surface, a slight dip in the land had obscured them from earlier view. By eleven o'clock the sand had merged into the longed-for iron-pebble strewn plains, and now the scrub was comparatively abundant all around, and the tough, wiry grasses which the camels loved appeared in greater profusion. Yet no signs of Fortunate Spring.
"It can't be far off now," said Bob, hopefully. "I'd better fix our position again before we go further, in case we might pass it."
"And that would be easily done, my lad," spoke Mackay. "I remember well that the water was in a mallee flat, just scrubby country like this, but there was no kind o' landmark except a fair-sized lime tree which grew beside it, an' I canna see any lime trees about here."