A matter which is easier, and for which straightforward ruling may be framed, concerns the navigation of craft upon the airway. At present, with comparatively few machines, there is no great need for any code of rules: one pilot, should he sight another, can easily steer clear. But as the air becomes peopled, and there are streams of traffic between landing grounds, it will be very necessary to have a scheme of rules--rules, say, for meeting and passing, and for flying by day or night. What is suggested is that, with some modifications, the laws of the sea should be adapted to the air. Craft approaching each other should, it is held, bear away to the right, and never pass nearer than 300 metres (328 yards). When flying at night, a system of lights is recommended: white showing ahead, green to starboard, red to port, and another white light astern. Just before alighting when travelling by day, it is suggested that a pilot should show a red triangular flag; or, at night-time, wave a white light. When flying in daylight, and finding himself in distress, it is advised that a pilot should show a red triangular flag, and at the same time suspend from his machine two black balls, hung one above another; or, in the same circumstances at night-time, wave a white lamp and extinguish his side lights. The reason, in such a case, for extinguishing the side lights would be so as to show to other pilots only one lamp--the white one. This single white light will be the night signal of an ordinary balloon, and it will be the rule for all power-driven craft to make way for it, and an aeroplane or an airship, say when its machinery has broken down, being in the same position as a free balloon, will wave this white-light signal so as to warn other pilots to keep clear. By degrees, as air-traffic grows, new laws and regulations will need to be applied. But at present, save for restrictions such as have been cited, an aerial tourist wings unfettered flight. The motorist has a speed limit of 20 miles; but the airman, 3000 feet aloft, has none; and, save for certain areas out of bounds, the sky is free wherever he may fly. Presently, however, the law must have its say, and air transit will be regulated as is the traffic of the land or sea. Already, in fact, our Home Office, after consulting experts, has its scheme of rules on paper; but these will not be enforced till the need comes. [3] Since this list was compiled by the authorities, an additional landing area, in the neighbourhood of Folkestone, has been prescribed by law. CHAPTER XIX TWENTY YEARS HENCE The air, our future highway--Crossing the Atlantic--New York, for the week-end, by flying Pullman--Mail-carrying by air--The organisation of airways and air-stations.