 Complete the following phrase:  In September 1917, Crawfordwho had been promoted to the position of squadron intelligence officerjoined 48 Squadron RFC, for which he again took aerial photographs during reconnaissance missions. While on one flight in February 1918, Crawfords aircraft was shot at and forced to land in German-held territory; he and his pilot were taken as prisoners of war. He was initially imprisoned at Landshut in Bavaria, from where he tried to escape by swimming down the River Isar; the river current proved too strong and he was soon recaptured. He was then transferred to Holzminden prisoner-of-war camp, where he was aware of an escape plan involving tunnelling out of the camp, but did not take part. Instead he spent much of his time working on Man and his Past and reading works by Wells, Carl Jung, and Samuel Butler. Crawford remained in the camp for seven months, until the 