Early in 1916 this deadly weapon of aerial warfare made its appearance, and for a while the civilian population of England and France read with dismay of its conquests. Mounting high into the clouds, it would await its victim. The moment a machine of the Allies appeared beneath it, the _Fokker_ turned its nose straight down and went speeding in the direction of its prey, opening fire as soon as it got within range. There was no use of the unfortunate airplane trying to escape. The _Fokker_ could, by wobbling its nose slightly in spiral fashion as it descended, produce, not a straight stream of bullets ahead of it but a cone of fire from its machine gun, with the victim in the center of the circle. Whichever way the latter turned to escape it met a curtain of bullets which could destroy it. The Allied machines could only combat it in groups of three and for a time at least it held supremacy in the skies. When itself pursued by a superior number of planes, it was quick as an acrobat, and speedy at climbing, so that it very seldom could be caught. This was the machine in which the two famous German airmen, Immelmann and Boelke performed some of their most daring exploits. It traveled at a speed of more than 100 miles per hour and could perform surprising feats with the most alarming ease. But while the _Fokker's_ début over the trenches caused the British House of Commons to debate the new peril gravely, French and British airmen sprang quickly and gaily to the challenge. Heedless of the danger, they braved the bullets of the _Fokker_ in order to get a better view of its mechanism, and they soon answered it with swift and powerful machines like the British _De Havilland_. It was only a short while before the Fokker monoplane was "behind the times." Faster machines with greater climbing powers overtook it in the skies and swooped down upon it from superior altitudes, as it had swooped down upon so many of its victims. Its day of triumph at an end, it withdrew to the seclusion of its hangar, and the _Fokker biplane_ replaced it in the air. This in its turn became the steed of many of Germany's star aerial performers. Now came the days when Captain Baron von Richthofen held forth in the heavens with his squadrons of variegated planes which the British airmen nicknamed "Richthofen's circus." These queerly "camouflaged" planes were German Albatroses. The _Albatros_ was one of the best designed of the German airplanes, and although the first models produced were not remarkable for their speed, they were good climbers and weight-carriers and thoroughly reliable. They were later developed in two distinct types: a fast "speed scout" biplane single-seater, equipped with two machine guns both firing across the propeller; and a slower reconnaissance airplane, for general service over the lines. The latter carried both a pilot and an observer, and had two machine guns, one to be fired by each of them.