It is a curious fact that in certain sectors the aviator's life is made miserable by this ceaseless bombing, while in other places a species of unwritten understanding permits him to sleep, at least, in peace. I have a friend in a far-off escadrille who has to jump out of bed and dive for the dugouts nearly every clear night, when the sentry hears the unmistakable Mercedes hum close overhead, the shutting off of the motor, and the ominous rush of air as the Huns descend on their mark. He knows that the Germans get as good as, or better than they give--but the knowledge does not make up for lost sleep. In my sector, on the other hand, we could blow the Boche aerodromes to atoms and they could probably do as much for us, but neither side has started this useless "strafing." Just before an attack, such bombing might be of military value; otherwise it only harasses vainly men who need what sleep they get, and destroys wealth on both sides, like exchanging men in checkers without profiting in position. I have heard parlor warriors at home say, "By all means make war as unpleasant as possible--then it won't happen again." But there is a limit to this, when nothing of tactical value is accomplished. The aerodromes are the headquarters of the different squadrons, each of which is specialized in some type of work. Military aviation divides itself into certain groups, requiring different types of machines and different training for pilot or observer. These groups are day-bombing, night-bombing, observation, photography, artillery fire-control, and chasse. I would like to tell you all about the different buses used, but of course one is not at liberty to do so. In general, bombing-machines are rather large two-seaters or three-seaters, designed to rise to great heights, where they are very fast, and capable of carrying heavy loads for long distances. They are, naturally, well armed, but depend (for safely carrying out their missions) principally on their speed at altitudes of eighteen thousand feet or more. Photography, observation, and artillery control machines, on the other hand, must be fast at lower altitudes, handy in a fight, and speedy climbers. They are, so far as I know, always two-seaters, and are really the most important of all aeroplanes. I believe that all the allied designers should work together to produce a single uniform type of two-seater--small, quick to maneuver, and very fast up to fifteen or sixteen thousand feet. Such machines, flying about their work in small groups, are truly formidable things for single-seater scouts to attack, as they are nearly as fast and handy, and have the enormous advantage of being able to shoot backward as well as forward. With light double-controls for the machine-gun man or observing officer (who would take a few lessons in emergency flying), they could not be brought down by killing the pilot--a most valuable feature.