Thermograph, thermistor, and thermometer readings at a 30 m. deep bergschrund from June 6 to July 22, 1953, showed that there was little direct relationship between air temperatures outside and at the bottom of the Schrund. The air temperature inside ranged from −3.7° C. (253° F.) to +0.5° C. (32.9° F.), but from July 2 onwards it oscillated between –0.5° C. and +0.5° C., with a 3–4 day periodicity. The ice temperature at the bottom of the schrund behaved similarly, though it was about 0.5° C. colder. The oscillations may have been caused by the interplay of flowing melt water (source of heat) and air drainage in quiet weather (source of cold). The granite-gneiss headwall, where not sheathed by refrozen melt water, appeared to be chemically and mechanically unweathered, which supported the conclusions of Battle’s earlier tests in deep bergschrunds and in the laboratory.