Naturally, the purchase of a hundred machines does not represent the total outlay, in connection with the establishment of a well-equipped air-corps. An organisation must be built up round these machines, and there must be men not only to fly them, but to keep them in a state of efficiency; and there is the need, also, of housing the air-fleet. The question of providing sheds for a fleet of machines is an important one. Aeroplanes must be well housed, or their depreciation is rapid. Whatever sheds are provided must, apart from being strong and weather-proof, be portable as well. Under the same heading, also, should come the workshops—some of them portable—necessary to cope with repairs and renewals in connection with machines. This, too, is an important item, as first-class repair work is an essential feature in the organisation of any air service. An estimate of the money that should be expended upon sheds and repair-shops—for a fleet of a hundred aeroplanes—places the amount at £20,000. Money should not be stinted in this direction; good sheds, and efficient repairs, should both tell their tale, when the aeroplane is used in a campaign. [Illustration: PILOT AND "OBSERVER." Photo, M. Roe. The above photograph shows a military-type Breguet biplane, as used in the French manœuvres, with pilot and observer in their places.] Now it is necessary to touch upon the question of military flying grounds, and the expense incurred in keeping them in proper order; also the sum of money necessary to provide a sufficient number of motor transport lorries for the air-fleet. As has been explained, the plan generally adopted is for an aeroplane to be transported from point to point on a lorry, and followed by a repair-car. In regard to the English trials of war aeroplanes, a point is made—in connection with the size of the packing-cases for machines—of the possibility of transporting aircraft by railway in time of war. Undoubtedly, under favourable circumstances, this would provide a rapid method of bringing up machines from a distance. Under the headings of the expenditure upon flying grounds, and the provision of motor-lorries to follow aeroplanes, and act as transport waggons, a reasonable estimate of the sum to be expended—in connection with a fleet of a hundred machines—is £20,000. The sum of £100,000 should be sufficient, not only to purchase a hundred war aeroplanes, but to equip the corps with sheds and repair-shops, and also to maintain flying grounds, and provide an adequate number of motor-lorries. This amount allocated for machines and incidentals, a Government would find itself face to face with the question of providing officers and men for the air-corps. Pay for this corps should, it is considered, be represented by an annual sum of approximately £60,000. III. Question of renewals—General cheapness of an air-corps, as compared with other forms of armament.