Principally our work consists of keeping German airmen away from our lines, and in attacking them when opportunity offers. We traverse the brown band and enter enemy territory to the accompaniment of an antiaircraft cannonade. Most of the shots are wild, however, and we pay little attention to them. When the shrapnel comes uncomfortably close, one shifts position slightly to evade the range. One glances up to see if there is another machine higher than one's own. Low and far within the German lines are several enemy planes, a dull white in appearance, resembling sand flies against the mottled earth. High above them one glimpses the mosquito-like forms of two Fokkers. Away off to one side white shrapnel puffs are vaguely visible, perhaps directed against a German crossing the lines. We approach the enemy machines ahead, only to find them slanting at a rapid rate into their own country. High above them lurks a protection plane. The man doing the "ceiling work," as it is called, will look after him for us. TACTICS OF AN AIR BATTLE Getting started is the hardest part of an attack. Once you have begun diving you're all right. The pilot just ahead turns tail up like a trout dropping back to water, and swoops down in irregular curves and circles. You follow at an angle so steep your feet seem to be holding you back in your seat. Now the black Maltese crosses on the German's wings stand out clearly. You think of him as some sort of big bug. Then you hear the rapid tut-tut-tut of his machine gun. The man that dived ahead of you becomes mixed up with the topmost German. He is so close it looks as if he had hit the enemy machine. You hear the staccato barking of his mitrailleuse and see him pass from under the German's tail. The rattle of the gun that is aimed at you leaves you undisturbed. Only when the bullets pierce the wings a few feet off do you become uncomfortable. You see the gunner crouched down behind his weapon, but you aim at where the pilot ought to be--there are two men aboard the German craft--and press on the release hard. Your mitrailleuse hammers out a stream of bullets as you pass over and dive, nose down, to get out of range. Then, hopefully, you re-dress and look back at the foe. He ought to be dropping earthward at several miles a minute. As a matter of fact, however, he is sailing serenely on. They have an annoying habit of doing that, these Boches.