When undertaking cross-country flights over strange land an airman finds his way by a specially-prepared map which is spread out before him in an aluminium map case. From the illustration here given of an aviator's map, you will see that it differs in many respects from the ordinary map. Most British aviation maps are made and supplied by Mr Alexander Gross, of the firm of "Geographia", London. Many airmen seem to find their way instinctively, so to speak, and some are much better in picking out landmarks, and recognizing the country generally, than others. This is the case even with pedestrians, who have the guidance of sign-posts, street names, and so on to assist them. However accurately some people are directed, they appear to have the greatest difficulty in finding their way, while others, more fortunate, remember prominent features on the route, and pick out their course as accurately as does a homing pigeon. Large sheets of water form admirable "sign-posts" for an airman; thus at Kempton Park, one of the turning-points in the course followed in the "Aerial Derby", there are large reservoirs, which enable the airmen to follow the course at this point with the greatest ease. Railway lines, forests, rivers and canals, large towns, prominent structures, such as gasholders, chimney-stalks, and so on, all assist an airman to find his way. CHAPTER XLIII. The First Airman to Fly Upside Down Visitors to Brooklands aerodrome on 25th September, 1913, saw one of the greatest sensations in this or any other century, for on that date a daring French aviator, M. Pegoud, performed the hazardous feat of flying upside down. Before we describe the marvellous somersaults which Pegoud made, two or three thousand feet above the earth, it would be well to see what was the practical use of it all. If this amazing airman had been performing some circus trick in the air simply for the sake of attracting large crowds of people to witness it, and therefore being the means of bringing great monetary gain both to him and his patrons, then this chapter would never have been written. Indeed, such a risk to one's life, if there had been nothing to learn from it, would have been foolish. No; Pegoud's thrilling performance must be looked at from an entirely different standpoint to such feats of daring as the placing of one's head in the jaws of a lion, the traversing of Niagara Falls by means of a tight-rope stretched across them, and other similar senseless acts, which are utterly useless to mankind. Let us see what such a celebrated airman as Mr. Gustav Hamel said of the pioneer of upside-down flying.