These observation balloons are used by both sides in conjunction with the artillery. A man sits up in the balloon with a wireless apparatus and directs the firing of the guns. From his point of vantage he can follow the work of his own artillery with a remarkable degree of accuracy and at the same time he can observe the enemy's movements and report them. The Germans are very good at this work and they use a great number of these balloons. It was considered a very important part of our work to keep them out of the sky. There are two ways of going after a balloon in a machine. One of them is to cross the lines at a low altitude, flying so near the ground that the man with the anti-aircraft gun can't bother you. You fly along until you get to the level of the balloon, and if, in the mean time, they have not drawn the balloon down, you open fire on it and the bullets you use will set it on fire if they land. The other way is to fly over where you know the balloons to be, put your machine in a spin so that they can't hit you, get above them, spin over the balloon, and then open fire. In going back over the line you cross at a few hundred feet. This is one of the hardest jobs in the service. There is less danger in attacking an enemy's aircraft. Nevertheless, I had made up my mind either to get those balloons or make them descend, and I only hoped that they would stay on the job until I had a chance at them. When our two hours' duty was up, therefore, I dropped out of the formation as we crossed the lines and turned back again. I was at a height of fifteen thousand feet, considerably higher than the balloons. Shutting my motor off, I dropped down through the clouds, thinking to find the balloons at about five or six miles behind the German lines. Just as I came out of the cloud-banks I saw below me, about a thousand feet, a two-seater hostile machine doing artillery observation and directing the German guns. This was at a point about four miles behind the German lines. Evidently the German artillery saw me and put out ground signals to attract the Hun machine's attention, for I saw the observer quit his work and grab his gun, while the pilot stuck the nose of his machine straight down. But they were too late to escape me. I was diving toward them at a speed of probably two hundred miles an hour, shooting all the time as fast as possible. Their only chance lay in the possibility that the force of my dive might break my wings. I knew my danger in that direction, but as soon as I came out of my dive the Huns would have their chance to get me, and I knew I had to get them first and take a chance on my wings holding out. Fortunately, some of my first bullets found their mark and I was able to come out of my dive at about four thousand feet. They never came out of theirs!