Once more we pulled out over the soft snow, but although a little refreshed by our good sleep we found the work extremely trying and toilsome. We crossed an ice donga, and about four miles out reached the edge of a second donga. Here we determined to leave everything but our sledge, tent, sleeping-bag, cooking apparatus, oil and food, and make a forced march to the Drygalski depot. Accordingly we camped and having fixed up our depot, we marked the spot with a little blue flag tied on to an ice-axe. The sledge thus lightened was far easier to pull, and having crossed the donga by a snow-bridge we pulled steadily onwards, Mawson occasionally sweeping the horizon with our field-glasses in hopes of sighting our depot. Suddenly he exclaimed that he saw the depot flag distinctly on its ice mound, about seven miles distant, but when Mackay and I looked through the glasses neither of us could see any trace of the flag. Mawson considered that both of us must be snow-blind, but when he looked again he at once exclaimed that he could no longer see the flag. The horizon seemed to be walloping up and down, just as though it was boiling, evidently the result of a mirage. Mawson, however, was so confident that he had seen the flag, well round on the starboard bow of our sledge that we altered our course, and after going a little over a mile, we were rejoiced to hear that he could distinctly see the depot flag. Full of hope we kept on sledging for several miles farther, but at midnight when the temperature had fallen to zero I felt that one of my big toes was getting frost-bitten. All day my socks had been wet through, and with the sudden fall of temperature the water in the socks had turned to ice. So we halted for me to change my socks and for all of us to have a midnight meal, and much refreshed we started off again, thinking that at last we should reach our depot, or at all events the small inlet a little over a mile from it. But "the best laid schemes of mice and men gang aft agley." There was an ominous white streak ahead of us with a dark streak just behind it, and soon we saw that this was due to a ravine in the snow and ice surface interposing itself between ourselves and our depot, and shortly afterwards we reached the near cliff of the ravine. This ravine was 200 yds. broad, and from 30 to 40 ft. deep; and it was bounded by a vertical cliff or very steeply inclined slope on the north-west side, and by an overhanging cliff on the south-east side. Inland the ravine extended as far as the eye could reach.