A Belgian doctor who called upon me in London in April, immediately on his arrival from Belgium, told me of a dramatic account of the British air raid on the railway at Courtrai, given to him by the guard of a train which had been standing in the station at the time. The man had been wounded, and my Belgian friend had been called in to attend him. The guard said that, on the appearance of the British aeroplane over the station, a number of German soldiers rushed out on to the line and started to fire at the raider with their rifles. The British airman suddenly planed down, and the Germans, thinking he had been hit, streamed together with shouts of joy into a dense crowd to await his landing. But their triumph was short-lived. When he was not more than a hundred feet from the ground the raider dropped four bombs in rapid succession right into the midst of the crowd; then, with a quick jerk of his elevating plane, soared aloft and away. The bombs worked havoc among that dense mass. A score or more of soldiers and railwaymen were killed, and as many more wounded. The train was wrecked; and as for the guard, who was a German, the doctor said he became positively panic-stricken at the mere thought of what he had seen that day. The development which the war has produced in what I may call air tactics is positively prodigious. It must be remembered that, at the outset, the aeroplane had practically never been tried on active service, for the experiments made in the Tripoli and Balkan wars, and by the French in Morocco, were more in the nature of sporting flights than serious military tests. Our pilots have had to learn by their own experience in the air--and a gallant and bravely bought experience it has been--the fighting tactics of the aeroplane. They have had to learn to distinguish “by silhouette” the different types of German machine, and to discover the most efficacious way of dealing with each one, according as the position of the propeller and of the driving-seat in relation to the planes restricts the field of fire of the enemy machine-gun. They have had to learn for themselves how to manœuvre for position when tackling an adversary in the air, to find out the vital spots in the different types of enemy machines. Active service has brought them their first taste of flying under fire. They have learnt to keep a cool head with high-explosive shrapnel from the enemy “Archies” bursting all around them, and bullets from the machine-guns of attacking aeroplanes whistling about their ears or rustling through the canvas stretches of their wings. They have learnt to make those twists and turns, those swoops and dives, which I have so often seen them making high in the air above the lines, to avoid those pretty little puffs which carry instant destruction in their folds of white smoke.