But the reconnoitring aeroplane is by no means allowed to have things all its own way. Anti-aircraft guns fill the space about it with bursting shrapnel, other aeroplanes rise to attack it, machine guns spit bullets at it. If no damage is done, the unfortunate observer is kept far too busy to worry about what is going on down below him. On one occasion we were conducting a series by the help of aerial observation. It was a beautifully clear day, and to our astonishment our first three rounds were signalled "Not observed." Then came a message, "Observation impossible, am coming home," and in about a minute we saw our aeroplane "coming home" at top speed, closely pursued by three hostile machines. Sometimes one is fortunate enough to witness an air duel, which is one of the most magnificent sights imaginable. The anti-aircraft guns are silent, the risk of hitting their friends is too great, and high up above the ground the machines wheel and turn and dive at angles that seem incredible to the watchers below. Very faintly comes the roar of the engines and the staccato rattle of machine guns and automatic pistols. At last one of the machines, finding itself overpowered, dives suddenly, and then, straightening its course, makes a long vol plané to the safety of its own lines, followed by its antagonists till the anti-aircraft fire becomes too hot for them. Or there is a sudden silence, a curious fluttering as of a winged bird, and, quite slowly as it seems, a torn mass of metal and canvas dives headlong to earth. Or perhaps one morning a dull drone attracts one's attention, and, looking up, one sees against the deep blue of the sky an aerial squadron, their wings almost pure white in the sun, a flight of sinister wild geese, carrying bombs to the destruction of some important railway centre. Flanders is much to be recommended as a suitable spot in which to undergo the cure of ennui.