Again, the radius of activity of these whirlies was strictly limited; objects directly in their path only being disturbed. For instance, Laseron one day was skinning at one end of a seal and remained in perfect calm, while McLean, at the other extremity, was on the edge of a furious vortex. Travelling over the sea the whirlies displayed fresh capabilities. Columns of brash-ice, frozen spray and water-vapour were frequently seen lifted to heights of from two hundred to four hundred feet, simulating water spouts. Reverting to the afternoon of March 19. Beyond the strange stillness of the immediate vicinity, broken occasionally by the tumult of a passing, wandering whirly, an incessant, seething roar could be heard. One could not be certain from whence it came, but it seemed to proceed either from the south or overhead. Away on the icy promontories to the east and west, where the slopes were visible, mounting to an altitude of several thousand feet, clouds of drift-snow blotted out the details of the surface above a level of about six hundred feet. It certainly appeared as if the gale, for some reason, had lifted and was still raging overhead. At 7.30 P.M. the sound we had heard, like the distant lashing of ocean waves, became louder. Soon gusts swept the tops of the rocky ridges, gradually descending to throw up the snow at a lower level. Then a volley raked the Hut, and within a few minutes we were once more enveloped in a sea of drifting snow, and the wind blew stronger than ever. The duration of the lulls was ordinarily from a few minutes to several hours; that of March 19 was longer than usual. In the course of time, after repeated observations, much light was thrown on this phenomenon. On one occasion, a party ascending the ice slopes to the south met the wind blowing at an elevation of four hundred feet. At the same time snow could be seen pouring over the "Barrier" to the west of the Winter Quarters, and across a foaming turmoil of water. This was evidently the main cause of the seething roar, but it was mingled with an undernote of deeper tone from the upland plateau--like the wind in a million tree-tops. In the early spring, while we were transporting provisions to the south, frequent journeys were made to higher elevations. It was then established that even when whole days of calm prevailed at the Hut, the wind almost without exception blew above a level of one thousand feet. On such occasions it appeared that the gale was impelled to blow straight out from the plateau slopes over a lower stratum of dead-air. An explanation was thereby afforded of the movement of condensation clouds which appeared in the zenith at these times. A formation of delicate, gauzy clouds developed at a low altitude, apparently in still air, but doubtless at the base of a hurricane stratum. Whirling round rapidly in eddying flocculi, they quickly tailed away to the north, evaporating and disappearing.