In the carrying of mails, and for bearing urgently-consigned goods, there will be another field for reliable, fast-flying craft; and already, in actual tests which have been made, the value of the air-mail has been demonstrated. At Hendon, for instance, towards the end of 1911, an experiment was performed in which the Post Office showed interest. The object was to carry special letters and postcards, packed in ordinary mail-bags, between the aerodrome and a landing ground at Windsor; and in spite of bad weather, with treacherous winds and rain, flights were made almost daily and at high rates of speed. Letters and postcards borne thus through the air had reached, when the experiment ended, a total of 130,000. But before a public service could be installed machines would need, of course, to be reliable. They would be required to start punctually to the minute and to fly day after day without mishap, defying all weather save the worst of gales. And such efficiency will in fact be reached: it is a question merely of time. The aeroplanes used in this Hendon test were small and of low power; hence, despite the courage and experience of their pilots, they were at the mercy of gusty winds. But the air-mail of the future--large, metal-built, and driven by many motors--will thrust its way, unscathed, into the teeth of a gale of wind. Picture the start of such a craft, in the days when there is, say, an air-service between London and St. Petersburg. The mail-bags are borne swiftly to the aerodrome, and here stands the machine. Its widespread sustaining planes are fashioned from plates of metal--a metal light and yet amazingly strong; and between the planes, with a wedge-shaped bow, lies the car or body of the machine, with outlook windows along its front, and doors upon either side. Behind the lifting wings there are metal propellers; and sternwards the craft tapers until it ends with the control planes and rudder. In the hull, just behind the fore-car, men of the postal service are busy with the storage of mails; then, when her load is all aboard, appear the crew of three who are to voyage through the air. First comes the air-mail driver; he is in supreme control; and with him is a mechanic, a highly skilled man, whose task it is to tend the motors and see that they, and all the other working parts, are running smoothly during the hours that the machine is in flight. The third man to enter the fore-car is an official of the Post Office, who travels in charge of the mails. The sliding door in the hull is closed; men step back away from the machine; and upon her controlling platform the pilot, leaning forward slightly, pulls over a lever. Instantly, as he does so, there comes a throb and a hum; the engines wake to life and the big propellers, flickering faster and faster, drive astern a screaming gale of wind. Then, moving forward gracefully and with quickly gathering speed, the air-mail rises and is lost to view.