Reconnoissance is dangerous work, and is constantly growing more so, as anti-aircraft guns are improved. These guns are mounted on a revolving table, upon which is a mirror in which the airplane shows as soon as it comes within range of the gun. With an instrument designed for the purpose, the crew get the flyer's altitude; and with another, the rate at which he is traveling. They aim the gun for the proper altitude, make the correct allowance for the time it will take the shell to reach him, and as they have an effective range of over 30,000 feet, there is reason to worry. Yet by zig-zagging and other devices, the aviators are rarely brought down by anti-aircraft guns. The small scout machines with a wing spread of not more than thirty feet are not visible to the naked eye when at an altitude of over 10,000 feet, and are therefore safe from these guns at this height. But reconnoissance, to be effective, must be done at a much lower altitude, and sometimes the machine must remain under fire for a considerable period of time. Poiret, the French aviator, fighting with the Russians, with a captain of the General Staff for an observer, was under rifle and shell fire for about twenty minutes. His machine was up about 4000 feet. Ten bullets and two pieces of shell hit his airplane, but he never lost control. The captain was shot through the heel, the bullet coming out of his calf; but he continued taking notes. They returned in safety to their lines. I also did some work in directing artillery fire. For this my machine was equipped with a wireless apparatus for sending. No method has yet been devised whereby an airplane in flight can receive wireless messages. In directing the fire of the big guns, the aviator seeks to get directly over the object that is under fire, and to signal or send wireless messages in regard to where the shells land. After the aviator is in position, the third shot usually reaches the target. I am not yet one of the great aces, and will not, therefore, tell you about any of my air battles. I hope some day you may read of them and that I may come to have the honor of being named with Lufbery, Guynemer, Nungesser, Fonk, Bishop, Ball, Genét, Chapman, McConnell, Prince, Putnam, and other heroes of the air. Lieutenant R.A.J. Warneford, who won the Victoria Cross for destroying a giant Zeppelin, is one of the greatest of these; at least, he performed a feat never accomplished before and never since.