In the very large courtyard a tent operating-hospital was established. The white attendants were waiting within in the pallid obscurity, among tables, glass jars, and instruments. The surgeon's wagon, with hot-water and sterilising apparatus, was waiting without. The canvas organism was a real hospital, and the point about it was that it could move off complete at twenty-five minutes' notice and set itself up again in any other ordained location in another twenty-five minutes. Another short ride, and we were in an aviation park, likewise tented, in the midst of an immense wheatfield on the lofty side of a hill. There were six hangars of canvas, each containing an aeroplane and serving as a dormitory; and for each aeroplane a carriage and a motor--for sometimes aeroplanes are wounded and have to travel by road; it takes ninety minutes to dismount an aeroplane. Each corps of an army has one of these escadrilles or teams of aeroplanes, and the army as a whole has an extra one, so that, if an army consists of eight corps, it possesses fifty-four aeroplanes. I am speaking now of the particular type of aeroplane employed for regulating artillery fire. It was a young non-commissioned officer with a marked Southern accent who explained to us the secret nature of things. He was wearing both the Military Medal and the Legion of Honour, for he had done wondrous feats in the way of shooting the occupants of Taubes in mid-air. He got out one of the machines, and exhibited its tricks and its wireless apparatus, and invited us to sit in the seat of the flier. The weather was quite unsuitable for flying, but, setting four men to hold the machine in place, he started the Gnome motor and ran it up to two thousand revolutions a minute, creating a draught which bowed the fluttered wheat for many yards behind and blew hats off. And in the middle of this pother he continued to offer lucid and surprising explanations to deafened ears until his superior officer, excessively smart and looking like a cross between a cavalryman and a yachtsman, arrived on the scene swinging a cane.