As the reconnoitring machine moves out over the enemy, the pilot will be busy with the control of his machine. If the weather proves very favourable, his task will be a comparatively light one. All that he will need to do is to see that he is steering accurately upon the course laid down by the observer, and that his altitude remains at the level chosen. He will also listen attentively to the running of his engine, and occasionally note the number of revolutions it is making, as recorded by an indicator placed before him. If a reconnoitring flight has to be undertaken in adverse conditions, say with a gusty, treacherous wind blowing, the task of the pilot will be an extremely arduous one. Apart from the difficulty of keeping his craft upon a proper course, he will be faced with the nerve-racking task of preventing it from "side-slipping," under the onslaught of vicious gusts of wind. The "side-slip" which an aeroplane may make in a gusty wind is, indeed, a very unpleasant experience for those who are on board it. What happens is this: under the influence of a sudden gust, the machine heels over until it reaches an angle when forward motion is replaced by a swift, sickening slide sideways. A machine may "side-slip" in this fashion, for an appreciable distance, before the pilot is able to regain control of it. An example may be cited of an airman who slid down from an altitude of more than 800 feet, until he was within a couple of hundred feet of the ground. There is only one thing to do when a machine begins to "side-slip" in this way. The pilot must alter the angle of his elevating planes, so that the aeroplane dives forward as well as slips sideways. This dive adds to the machine’s speed, and so checks the sideway fall; and, if his altitude is sufficient, the airman is able to regain control of his machine, and bring it back again upon an even keel, before there is danger of contact with the ground. In bad weather, as may be imagined, a reconnoitring trip may be a serious ordeal for the man at the levers. The responsibility for undertaking a flight, in unsuitable weather conditions, will fall upon the officer in command of the aviation depot. If, for example, the wind is too high for flying, it will be his duty to tell the Commander-in-Chief so, and delay the intended reconnaissance until conditions improve. The work of the pilot of the aeroplane, during a reconnoitring flight, has only been described so far; now we may deal with the task of the observer. He will, probably, have a busier time than the man at the levers. From the moment of leaving the ground, until the flight is finished, he will need to be on the alert. As the aeroplane approaches the enemy’s lines, he will pore over the map fixed in a frame before him. In addition to this map, he will be provided with pencil and notebook. Thus, when any portion of the enemy’s troops appear below him, his task will be perfectly clear.