When the wings of a machine are ready and have been sheathed with their fabric, and when its hull and chassis have been built, it finds its way into the assembling shop. The motor is bolted in its framework, the propeller fitted, and the whole construction receives a final overhaul. And then one morning it is wheeled out upon the aerodrome--its planes spotless and gleaming in the sun--and is tested for the first time in flight. In many cases, so great has been the progress in aeroplane building, that a new machine will do just what its designer intended it should; there is no longer any doubt as to the craft’s ability to take the air. But minor adjustments have usually to be made, none the less, before a machine is delivered to its purchaser; and in the case of a war machine, bought, say, for the Admiralty or the Army, it needs to perform--prior to being taken over--a series of special tests. It must show that it can ascend rapidly and fly at a certain speed, and it must raise a specified weight of fuel, in addition to that of its pilot and passenger. The War Office has prepared a list of its requirements for military machines of different types; and aeroplane builders, if they plan craft for Government acceptance, must be prepared to submit them to the trials arranged. A light scouting machine, when it is tested, must be able to lift its pilot and fuel sufficient for a flight of 300 miles, and it needs to vary its speed from 30 to 85 miles an hour. Larger machines, built for scouting, have to carry the weight of a pilot and observer and 80 lbs. of wireless apparatus; while a craft to be used in fighting must raise--in addition to its crew--the weight of a gun and ammunition; this is estimated to represent 300 lbs. What the maker usually does, when a craft intended for the Government has been built and given a preliminary testing, is to send it by way of the air either to Farnborough, where the Royal Aircraft Factory is situated, or to Eastchurch, in the Isle of Sheppey, where the Royal Naval Air Service has its headquarters. Then, with the pilot employed by the firm at its levers, and some military or naval airman as his passenger, the machine is subjected to its trials; and if it fails, say, to rise fast enough, or lifts an insufficient weight, it is returned to its constructor to be adjusted and improved. With sea-planes, naturally, there are tests upon the water, both as to a craft’s ability to rise and descend.