On the table in the centre of the room are the various instruments by the aid of which the aviators are enabled to figure out their magnetic courses. Every afternoon the map-room is crowded with aviators. Here all the plans for the raid are made, the courses figured and marked on individual charts, the photographs or plans of targets studied and the best methods of approaching the target discussed. In the evening the wind soundings made by the meteorological expert are reported and again the map-room is crowded with aviators figuring out "drift" and "ground speed" and making out charts which will facilitate their navigation when in the air. CHAPTER IV A NIGHT RAID Every precaution having been taken, the engines run, the controls tested, the compasses swung, the courses made out, the charts prepared, and the drift figured, the Bedouins sat down to dinner free from care or worry. The dinner hour was always set, winter or summer, at least two hours before the night's raid was to start. A guest of the Bedouin mess on the night of an important raid would have been surprised if told that the jolly, laughing officers, who apparently had no thought in the world other than the enjoyment of various wines and viands, were soon to set out on a pioneer raid against a far-distant German industrial centre. For the Bedouins made the best of the present; they all knew what a long-distance raid over Germany usually meant; many of their jolly comrades would not be seen again. So they made merry at dinner and drank each other's health. The wine, however, was light, and even the most reckless Bedouin drank it in tiny sips, for the work to be done was important. The personal dangers of the raid the reckless Bedouins might ignore, but they knew that these raids fitted into the general tactical plan of operations; consequently, every Bedouin was imbued with a spirit of determination in spite of an apparent frivolity. On entering the ward-room a few moments before dinner, the guest of the Bedouin mess would have been greeted joyfully by the officers who were singing lustily in perfect tune with a piano which was very much out of tune. A few moments later he would see these rollicking fellows stand silently at attention on the entry of the Commanding Officer until "Good-evening, gentlemen," from the C.O. granted them permission to "carry on."