August 23.—Starting early, I traced the course of the lake north–westerly for ten miles, and was then able to satisfy myself that it was a part of the same vast basin I had seen so much further to the north, it inclined here considerably to the westward, and this circumstance added to the high sandy ridges intervening between it and Flinders range fully explained the cause of our not having observed its course to the north of west from the hills near our depot. Crossing the sandy ridge bounding the basin of the lake, I was surprised to see its bed apparently much contracted, and the opposite shore distinctly visible, high, rocky and bluff to the edge of the water, seemingly only seven or eight miles distant, and with several small islands or rocks scattered over its surface. This was however only deceptive, and caused by the very refractive state of the atmosphere at the time, for upon dismounting and leading the horses into the bed of the lake, the opposite shore appeared to recede, and the rocks or islands turned out to be only very small lumps of dirt or clay lying in the bed of the lake, and increased in magnitude by refraction.
I penetrated into the basin of the lake for about six miles, and found it so far without surface water. On entering at first, the horses sunk a little in a stiff mud, after breaking through a white crust of salt, which everywhere coated the surface and was about one eighth of an inch in thickness, as we advanced the mud became much softer and greatly mixed with salt water below the surface, until at last we found it impossible to advance a step further, as the horses had already sunk up to their bellies in the bog, and I was afraid we should never be able to extricate them, and get them safely back to the shore. Could we have gone on for some distance, I have no doubt that we should have found the bed of the lake occupied by water, as there was every appearance of a large body of it at a few miles to the west. As we advanced a great alteration had taken place, in the aspect of the western shores. The bluff rocky banks were no longer visible, but a low level country appeared to the view at seemingly about fifteen or twenty miles distance. From the extraordinary and deceptive appearances, caused by mirage and refraction, however, it was impossible to tell what to make of sensible objects, or what to believe on the evidence of vision, for upon turning back to retrace our steps to the eastward, a vast sheet of water appeared to intervene between us and the shore, whilst the Mount Deception ranges, which I knew to be at least thirty–five miles distant, seemed to rise out of the bed of the lake itself, the mock waters of which were laving their base, and reflecting the inverted outline of their rugged summits. The whole scene partook more of enchantment than reality, and as the eye wandered over the smooth and unbroken crust of pure white salt which glazed the basin of the lake, and which was lit up by the dazzling rays of a noonday sun, the effect was glittering, and brilliant beyond conception.
[Very similar appearances seem to have been observed by Monsieur Peron, on the S. W. coast near Geographe Bay. “A cette epoque nous eprouvions les effets les plus singuliers du mirage; tantot les terres les plus uniformes et les plus basses nous paroissoient portees au dessus des eaux, et profondement dechirrees dans toutes leurs parties; tantot leurs cretes superieures sembloient renversees, et reposer ainsi sur les vagues; a chaque instant on croyoit voir au large de longues chaines de recifs, et de brisans qui sembloient se reculer a mesure qu’on s’en approchoit davantage.”—VOYAGE DE DECOUVERTES AUX TERRES AUSTRALES REDIGE PAR PERON.]
Upon regaining the eastern shore, I found that all I had been able to effect was to determine that the lake still continued its course to the N.W. that it was still guided as before, by a ridge like a sea shore, that its area was undiminished, that its bed was dry on the surface for at least six miles from the outer margin, and that from the increasing softness of the mud, occasioned by its admixture with water, as I proceeded there was every probability that still further west, water would be found upon the surface. Beyond these few facts, all was uncertainty and conjecture in this region of magic. Turning away from the lake, I retraced my steps towards the depot, and halted at dark after a stage of nearly forty miles. Here was neither grass nor water, and again I was obliged to tie up the unfortunate horses, jaded, hungry and thirsty.
During the night, I released one of the poor animals for an hour or two, thinking he would not stray from his companion, and might, perhaps, crop a few of the little shrubs growing on the sand ridges, but on searching for him in the morning he was gone, and I had to walk twelve miles over the heavy sand tracking him, the boy following along our outward track with the other horse, for fear of missing the man who was to meet us with water.
The stray horse had fortunately kept near the line we had followed in going to the lake, and I came upon him in a very weak and miserable condition, soon after the arrival of the man who had been sent to meet us with water. By care and slow travelling, we reached the depot safely in the afternoon, having crossed in going and returning, upwards of 100 miles of desert country, during the last three days, in which the horses had got nothing either to eat or drink. It is painful in the extreme, to be obliged to subject them to such hardships, but alas, in such a country, what else can be done.
In the evening, I directed the overseer to have every thing got ready for breaking up our encampment on the morrow, as the party had been fifteen days in depot, and little else than mud remained in the hole which had supplied them with water.