On taking into consideration the reduced number and strength of our horses, it was quite evident that we had but little prospect of being able to cross the tract of dry sandy country that had already occasioned us so much loss and trouble; yet there were many reasons to stimulate us to make the attempt. Not only had we now attained to within a very few miles of the longitude in which, from various geographical data, there are just grounds for believing that a large river may be found to exist, draining Central Australia, but the character of the country appeared strongly to indicate the vicinity of such a feature; added to which, the gradual decline in the elevation of the country, notwithstanding our increasing distance from the coast, tended towards the same conclusion. Nor should we omit the strong evidences that the remarkable ridges of drift-sand which encumbered the plains must in the first instance, have been brought from the interior by water, and then have been blown by the strong prevailing south-east winds across the country in a direction at least 50 degrees from that which they originally came from; this, with the clean water-worn appearance of the sand, the bold outlines of the hills seen to the far east, and the number of native fires observed in the same direction, must all tend to support the hypothesis that the western half of Australia is probably drained by a large river in about this meridian. I could not, therefore, help regretting more than ever that we should be driven back at such an interesting spot; but mature reflection convinced me that any further attempt with our present means, at this period of the year, was almost certain to be attended with the most disastrous results; I therefore decided upon adopting the only other useful course open to us--that of examining down to the sea the rivers already discovered. With this in view, we to-day fell back five or six miles across the ranges to a tributary to the Oakover, called the Davis, when one of the horses became so crippled by a strain in the loins that we were obliged to halt to give him a chance of recovery, affording me leisure to verify our position by observing another set of lunar distances, which I found to agree well with those formerly taken ten miles to the westward. Camp 78. DOWN THE OAKOVER RIVER. 12th September. We commenced the descent of the Davis, having much difficulty in getting along the sick horse, as it required the united strength of the party to lift him on his legs every time he fell, which he at last did so frequently that I ordered him to be shot, as it was hopeless to attempt to bring him on, and if left, he must have died of starvation. By 2.0 p.m. we reached the junction of the stream we were upon with the Oakover, and halted two miles south of Camp 72; most of the party being now dismounted, shoe-leather was beginning to get very scarce with us. Camp 79. 13th September.