Almost the whole of the Flanders country is intersected by waterways and canals. This is of extreme value to the air pilot, and aids him greatly in the matter of navigation. Railway systems there are in plenty, mostly following an east or west direction. The junctions of these railway lines are the nerve centers of the German Army in the field; they control entirely the supplies of reinforcements, ammunition, and supplies to the firing line. It is for this reason that so many of our own air raids have been made on Bruges, Courtrai, Roubaix, Lille, Tournai, and Douai. Each of these towns mentioned contains an important railway junction. The large majority of the Belgian towns in the enemy country, immediately behind the firing line, have been totally deserted by their inhabitants and the soldiers alike; it is not considered either safe or desirable to remain within the area of a conspicuous landmark, of which the enemy artillery can obtain an exact bearing with the utmost ease. Added to this, frequent allied air-raids, and the accurate firing of the Allied artillery have reduced them to untenable masses of fallen masonry. A point regarding aerial photography is worthy of note; if the surface of the earth has been disturbed in any way within two days previous to the photo being taken, that is, disturbed by the explosion of a shell, or a new path across a field made by the tramp of many feet, such disturbance will always show up prominently on the camera negative. CHAPTER X THE FIRST TRIP ACROSS THE LINE _Somewhere in France, Monday._ A most important entry in my little diary, this, the day of my first trip across the “lines.” And here in the privacy of my thoughts and of my pen let it be said that at first I was troubled with qualms of fear--qualms that I had experienced in the previous life after a stormy Channel crossing, or prior to a visit to my dentist. As I stood there on the dreary, wind-swept aerodrome in the chilly rays of the early morning sun, forebodings filled my mind. Visions of an awful death in mid-air, and a yet more awful vision of a downward rush of thousands of feet to the ground below. Comforting myself with the reflections that, after all, out of the large number of machines that must daily cross the lines the proportion of those reported missing was extremely small, I was roused from my pessimistic thoughts by the voice of the pilot, who was already in his seat enjoying the luxury of the last few puffs at his “gasper” (cigarette) before testing the engine. He invited me cordially to “hop in,” and once in to strap myself in securely. With his calm matter-of-fact air, which, incidentally cheered me up considerably, one would have thought that we were about to start for a motor run through Piccadilly and the Park rather than, as he so picturesquely styled it, “to play the part of a clay pigeon atop of a firework show.”