Our party consisted of four machines, each complete with pilot, observer, and several hundred rounds of ammunition. The job was an offensive patrol--that is to say, we were to hunt trouble around a given area behind the Boche lines. A great deal of the credit for our "mastery of the air"--that glib phrase of the question-asking politician--during the Somme Push of 1916, belongs to those who organised and those who led these fighting expeditions over enemy country. Thanks to them, our aircraft were able to carry out reconnaissance, artillery observation, and photography with a minimum of interruption, while the German planes were so hard pressed to defend their place in the air that they could seldom guide their own guns or collect useful information. To this satisfactory result must be added the irritative effect on enemy morale of the knowledge that whenever the weather was fine our machines hummed overhead, ready to molest and be molested. Offensive patrols are well worth while, but for the comfort of those directly concerned they are rather too exciting. When friends are below during an air duel a pilot is warmly conscious that should he or his machine be crippled he can break away and land, and there's an end of it. But if a pilot be wounded in a scrap far away from home, before he can land he must fly for many miles, under shell fire and probably pursued by enemies. He must conquer the blighting faintness which accompanies loss of blood, keep clear-headed enough to deal instantaneously with adverse emergency, and make an unwilling brain command unwilling hands and feet to control a delicate apparatus. Worst of all, if his engine be put out of action at a spot beyond gliding distance of the lines, there is nothing for it but to descend and tamely surrender. And always he is within reach of that vindictive exponent of frightfulness, Archibald the Ever-Ready. As we climbed to 4000 feet the machines above threw glints of sunlight on the screen of blue infinity. We ranged ourselves and departed. Passing the red roofs and heart-shaped citadel of Doulens and a jagged wood suggestive of a lion rampant, we followed the straight road to Arras. Arrived there, the leader turned south, for we were not yet high enough. As we moved along the brown band of shell-pocked desolation we continued to climb. Patches of smoke from the guns hovered over the ground at intervals. A score of lazy-looking kite balloons hung motionless.