The operation of the aeroplane mail service every day in the year except Sunday, encountering all sorts of weather conditions and meeting them successfully, has demonstrated the practicability of employing the aeroplane for commercial service, and the air mail organization has been able to work out problems of great value in the adaptation of machines to this character of service. From the inauguration of the service until the 10th of August, the flying operations were conducted by the army, in connection with its work of training aviators for the war. Since August 10 it has been operated entirely by the Post-Office Department, with a civil organization. When the service was started there was great divergency of opinion among aeronautical experts as to the possibility of maintaining a daily service regardless of weather conditions, and the opinion was held by many that it would have to be suspended during the severe winter months. The service has been maintained, however, throughout the year with a record of 92 per cent, gales of exceptional violence and heavy snow-storms being encountered and overcome. Out of 1,261 possible trips, 1,206 were undertaken, and only 55 were defaulted on account of weather conditions. During rain, fog, snow, gales, and electrical storms, 435 trips were made. Out of a possible 138,092 miles, 128,037 miles were flown. Only 51 forced landings were made on account of weather, and 37 on account of motor trouble. It has been demonstrated that flying conditions for such a commercial service as this, which is regulated by a daily schedule regardless of the weather, are very different from those of military flying. Aeroplanes designed wholly for war purposes are not suitable for commercial service, as they lack the strength necessary for daily cross-country work, with its incidental forced landings. Aeronautical engineers have developed for the Post-Office Department a stronger and more powerful plane suitable for commercial service while retaining the excellent flying qualities of the De Havilland machine. The De Havilland 4’s, which were transferred to the Post-Office Department after the signing of the armistice, are being reconstructed to fit them for commercial requirements. In specially constructed mail-carrying planes, for the building of which the department has called for bids to be opened June 2, a form of construction is called for which will enable a mechanic to make important minor repairs in flight, making it possible with a multiple motor to avoid forced landings. DANGER ELIMINATED