The few words at the end of this document tell an interesting story! Ted's first round of interrogation at Dulag Luft was in a cell which contained a powerful electric heater. The controls for this were located outside the cell and the guards would alter the temperature settings so that there were huge variations of temperature. This was part of the "softening up" procedure prior to interrogation. This is the "sweat-box" reference. Ted was then sent to Stalag Luft 4B. After several months he was returned to Dulag Luft for further interrogation. He spent 14 days in solitary confinement (the cooler). Ted understands that new radio equipment had been found in the wreckage of his Lancaster and the Luftwaffe wished to attempt to find out more about this equipment.