While in the sleeping-bag I tried to think out some rapid way of discovering what was wrong with the engine. The only conclusion to which I could come was that it would be best to proceed to the cave at eleven and three-quarter miles--Cathedral Grotto--and there remove the faulty cylinder, if the weather seemed likely to be favourable; if it did not, to go on independently with our man-hauled sledge. On December 4 the wind was still blowing about twenty miles per hour when we set to work on the machine. I poured some oil straight into the crank-case to make sure that there was sufficient, and we also tested and improved the ignition. At four o'clock the wind dropped, and in an hour the engine was started. While moving along, the idle cylinder was ejecting oil, and this, together with the fact that it had no compression, made me hope that broken piston-rings were the source of the trouble. It would only take two hours to remove three cylinders, take one ring from each of the two sound ones for the faulty one, and all might yet be well! These thoughts were brought to a sudden close by the engine, without any warning, pulling up with such a jerk that the propeller was smashed. On moving the latter, something fell into the oil in the crank-case and fizzled, while the propeller could only be swung through an angle of about 30 deg.. We did not wait to examine any further, but fixed up the man-hauling sledge, which had so far been carried by the air-tractor sledge, and cached all except absolute necessities. We were sorry to leave the machine, though we had never dared to expect a great deal from it in the face of the unsuitable conditions found to prevail in Adelie Land. However, the present situation was disappointing. Having stuffed up the exhaust-pipes to keep out the drift, we turned our backs to the aero-sledge and made for the eleven-and-three-quarter-mile cave, arriving there at 8 P.M. There was a cheering note from Bage in the "Grotto", wishing us good luck. To avoid crevasses we steered first of all to the southwest on the morning of the 5th, which was clear and bright. After six miles the sastrugi became hard and compact, so the course was changed to due west. Shortly afterwards, a piece of rock ** which we took to be a meteorite, was found on the surface of the snow. It measured approximately five inches by three inches by three and a half inches and was covered with a black scale which in places had blistered; three or four small pieces of this scale were lying within three inches of the main piece. Most of the surface was rounded, except one face which looked as if it had been fractured. It was lying on the snow, in a slight depression, about two and a half inches below the mean surface, and there was nothing to indicate that there had been any violent impact.