on our right, that is to the north, dunes without old vegetation. The sand increased perceptibly in quantity. Then we turned to the south-west, and after that once more to the west. A pool, with an area of about 50,000 sq. m., the water of which had a temperature of 14°.2 C. at noon, was, on the evidence of my new guides, a perfectly new creation. It was very interesting to observe the way in which the water here spread and worked its way north. The pool in question was evidently completely isolated and disconnected, for the water which reached it all came up from below; we actually saw it bubbling and boiling up with a loud noise, just as boiling water gurgles in the pot (Pl. 14). In two or three places the upgush was so strong that it formed domed pillars one dm. high, rippling unceasingly, like a miniature geysir. The air which accompanied this upgushing water formed bubbles and rings of froth round each little geysir, and these were drifted by the gentle east wind into the western bays. When I saw similar collections of froth a long way to the east of this position, I did not understand how they could have originated, but attributed them to the last storm which swept across the country. During the time we remained on the shore of this pool — and it was entirely surrounded by drift-sand — we observed the water distinctly rising. Owing to the constant upflow in the middle there was a slow centrifugal movement outwards towards the periphery, and in two or three places, where the shore was flat, small arms or emissaries were being formed, which hastened to empty themselves into the little hollows at the sides. Hence the shape and outline of the newly formed pools were determined by the dunes which stood around them. Strangely enough, the water here was fresher than it was at the two adjacent Camps Nos. CLXXII (sp. gr. = 1.0069) and CLXXIII (sp. gr. = 1.0059), whereas here the sp. gr. was only 1.0036: that is to say to us it was almost perfectly fresh. One would naturally suppose that the water which came boiling up out of the ground would be salter than that which came streaming along the surface. The fact that it was not so proves that the soil just here was not especially salt; indeed it may perhaps be taken as a proof that it had been a freshwater lake up through the sedimentary deposits of which the water was making its way.
The water was not perfectly clear, and I only found out where the bottom was by sending in a Loplik who could swim, to measure the depth with two of the tent-spars. In the pool there was a jardang, which even then was not in the slightest degree softened by the water. The greatest depth amounted to 2.22 m. I may mention that the whole of this pool, and innumerable others in the course of the day's march were all formed since my two attendants, the Cossack Tschernoff and the Loplik Tokta Achun, son of Kuntschekan Bek, rode past them on their way out to me. Tschernoff had even drawn a sketch-map to show the way they had come; but there was no need of it, the tracks of their horses were quite sufficient. They had travelled diagonally across the pool, for it was at that time dry ground. Now on the way back, they rode straight down into the water on the west side and up out of it again on the opposite or east side. How far the track was continued across the 2.22 m. deep depression could not be determined; it is very possible therefore that seven days before there had likewise been a pool in the bottom of it which the men had forgotten. In another pool, smaller and shallower, they were able to retrace their
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