Another feature of the military airmen’s work was represented by the adverse weather conditions in which they flew. Here was a distinct and unmistakable evidence of progress. In 1910, at the autumn manœuvres, a wind of from twenty to twenty-five miles an hour had been the limit in which pilots had cared to ascend. But, in the 1911 manœuvres, reconnoitring machines were boldly taken up in winds of as great a velocity as thirty and thirty-five miles an hour; and, in one or two cases, machines were reported to have weathered winds blowing at the rate of forty miles an hour. From the military point of view, the actual demonstration of this wind-flying capacity of the modern aeroplane was of the utmost value. It meant that there was practically no delay in carrying out instructions. Instead of waiting, as he would have been obliged to do, occasionally, the previous year, before carrying out a reconnoitring flight, the airman was promptly in his machine, and away—despite the fact that a strong and gusty wind might be blowing. Another point demonstrated, beyond question, was the reliability of aeroplane engines. Pilot after pilot returned from aerial journeys without any mechanical trouble whatever; engine failure, at first so common a fault, was proved to have been almost eliminated. It was not merely a case of engine improvement; the careful work of the mechanics, in "tuning up" the motors, had a great deal to do with this immunity from breakdown. Such a proof of reliability was, as may be imagined, of great significance to those who were gauging the work of the aeroplane purely from, the military point of view. Practice, as has been said, permitted the observers in the reconnoitring aeroplanes to obtain significant results. A test which was carried out, purely to determine the accuracy of aerial observation, is worth describing. In this case, a fortified position, some little distance away from one of the aeroplane camps, had been largely redesigned. The officer in charge of the aeroplanes decided to call upon three observers, who knew nothing of the alterations to the position which had been carried out, to make a reconnoitring flight over the spot, and prepare rough maps showing the location of the defences. This, he thought, would provide a severe test of the accuracy of each officer’s observation. Previous to sending away the three machines upon their errand, the officer had obtained, from the Commander of the fortifications, an exact plan of the new defences; he was, therefore, in a position to check, even in details, the maps furnished by the air-scouts. The three airmen who set out upon this special reconnoitring mission, each carrying an observer with him, approached their destination by different routes. Each, as he came near the fortified position he was to reconnoitre, flew at an altitude of more than 3000 feet—the height specified as being fairly safe from artillery-fire.