What would the past generation have said of a man who had prophesied great armies fighting in the air? Even in the early months of the war there were but few who realized what an important part of the war was to be carried on in the newly conquered element. When the infantry saw an occasional box-kite-looking machine drifting slowly over the lines, struggling to keep itself aloft, how many, I wonder, foresaw that in a few months these machines would be swooping down on them like swallows, raking them with machine guns by day and bombing them by night? How many artillery officers laughed at the suggestion that a day was coming when thousands of great guns would be directed from the air? Yet in a few short months two great blind fighting giants, their arms stretching from the Belgian coast to the Swiss border, learned to see each other; and their eyes were in the air. The first aeroplanes to cross the lines carried no armament; they were for reconnaissance work only; they would fly a few miles back of the enemy lines, have a good look around, and then come back and report what they had seen. Often British and German machines would pass quite close to each other. Flying was considered sufficiently dangerous, not to add a further danger to it by attacking enemy machines. The Germans, however, because they greatly outnumbered the British in the air, had more eyes to see with; something had to be done; so rifles were carried by the British and a finer sport than shooting ducks came into vogue. This quickly led to the carrying of machine guns. Ingenuity in devising sights to compensate for the speed of our own machines and to gauge a proper deflection according to the speed and angle of approach of the enemy machine, soon decreased the advantage the enemy aviators had through superior numbers. For example, if our machine was flying at the rate of one hundred miles per hour and the enemy's machine was travelling past us in the opposite direction at an equal rate, our fore-sight nullified our motion and enabled us to shoot as if from a stationary base, while our back-sight helped us to gauge that imaginary point at which to shoot where our bullets and the enemy machine would meet. In other words, we shot at an enemy machine although we ourselves were travelling rapidly, exactly as a sportsman shoots at a bird on the wing.