That night we encamped only a few miles from the ridges, at a place where there was a little dry grass, and where both camels and horses were let go in hobbles.  Long before daylight on the following morning, old Jimmy and I were tracking the camels by torchlight, the horse-bells indicating that those animals were not far off; the camel-bells had gone out of hearing early in the night.  Old Jimmy was a splendid tracker; indeed, no human being in the world but an Australian aboriginal, and that a half or wholly wild one, could track a camel on some surfaces, for where there is any clayey soil, the creature leaves no more mark on the ground than an ant—­black children often amuse themselves by tracking ants—­and to follow such marks as they do leave, by firelight, was marvellous.  Occasionally they would leave some marks that no one could mistake, where they passed over sandy ground; but for many hundreds beyond, it would appear as though they must have flown over the ground and had never put their feet to the earth at all.  By the time daylight appeared, old Jimmy had tracked them about three miles; then he went off, apparently quite regardless of any tracks at all, walking at such a pace, that I could only keep up with him by occasionally running.  We came upon the camels at length at about six miles from the camp, amongst some dry clay-pans, and they were evidently looking for water.  The old cow, which was the only riding camel, was so poor and bony, it was too excruciating to ride her without a saddle or a pad of some sort, which now we had not got, so we took it in turns to ride the bull, and he made many attempts to shake us off; but as he had so much hair on his hump, we could cling on by that as we sat behind it.  It was necessary for whoever was walking to lead him by his nose-rope, or he would have bolted away and rubbed his encumbrance off against a tree, or else rolled on it.  In consequence of the camels having strayed so far, it was late in the day when we again started, the two horses looking fearfully hollow and bad.  The morning as usual was very hot.  There not being now a horse a piece to ride, and the water which one camel had carried having been drank by the animals, Peter Nicholls rode the old cow again, both she and the bull being much more easy to manage and get along than when we started from Youldeh.  Our great difficulty was with the nose-ropes; the calf persisted in getting in front of its mother and twisting her nose-rope round his neck, also in placing itself right in between the fore-legs of the bull.  This would make him stop, pull back and break his rope, or else the button would tear through the nose; this caused detention a dozen times a day, and I was so annoyed with the young animal, I could scarcely keep from shooting it many times.  The young creature was most endearing now, when caught, and evidently suffered greatly from thirst.