Bombing brought to being a number of crude devices in the first year of the War. Allied pilots of the very early days carried up bombs packed in a small box and threw them over by hand, while, a little later, the bombs were strung like apples on wings and undercarriage, so that the pilot who did not get rid of his load before landing risked an explosion. Then came a properly designed carrying apparatus, crude but fairly efficient, and with 1916 development had proceeded as far as the proper bomb-racks with releasing gear. Reconnaissance work developed, so that fighting machines went as escort to observing squadrons and scouting operations were undertaken up to 100 miles behind the enemy lines; out of this grew the art of camouflage, when ammunition dumps were painted to resemble herds of cows, guns were screened by foliage or painted to merge into a ground scheme, and many other schemes were devised to prevent aerial observation. Troops were moved by night for the most part, owing to the keen eyes of the air pilots and the danger of bombs, though occasionally the aviator had his chance. There is one story concerning a British pilot who, on returning from a reconnaissance flight, observed a German Staff car on the road under him; he descended and bombed and machine--gunned the car until the German General and his chauffeur abandoned it, took to their heels, and ran like rabbits. Later still, when Allied air superiority was assured, there came the phase of machine-gunning bodies of enemy troops from the air. Disregarding all antiaircraft measures, machines would sweep down and throw battalions into panic or upset the military traffic along a road, demoralising a battery or a transport train and causing as much damage through congestion of traffic as with their actual machine-gun fire. Aerial photography, too, became a fine art; the ordinary long focus cameras were used at the outset with automatic plate changers, but later on photographing aeroplanes had cameras of wide angle lens type built into the fuselage. These were very simply operated, one lever registering the exposure and changing the plate. In many cases, aerial photographs gave information which the human eye had missed, and it is noteworthy that photographs of ground showed when troops had marched over it, while the aerial observer was quite unable to detect the marks left by their passing.