Besides flyers, however, engineer officers to direct the upkeep of the equipment, supply officers to keep sufficient equipment on hand, and adjutants to keep the records and do other military work had to be especially trained. These men, absolutely essential to the maintenance of the Air Service organization, could be secured only after a detailed course of instruction. An engineers’ school, opened for a 12 weeks’ course at the Massachusetts Institute of Technology on January 12, graduated 590 men and discharged 228 before June 30; a supply officers’ school, opened at the Georgia School of Technology, graduated 852 men and discharged 111 from an eight weeks’ course before it was closed on May 11; and an adjutants’ school, opened at Ohio State University on January 12, graduated 789 and discharged 97 men in an eight weeks’ course before it was closed June 22. A six weeks’ course for armament officers and men to care for machine guns and bombs was opened at Fairfield, Ohio, on April 22, graduating 95 officers and 465 men by June 30, all of whom went forthwith overseas. Just at the end of the year a series of special schools in aerial gunnery were opened as the final step in the flyers’ training in this country, graduating 102 pilots, 111 observers, and 101 fighting observers by June 30. Also a special course for compass officers was opened at Camp Dick, Texas, on April 10, with 53 graduates, and another course at the same time for a score of navigation officers. Radio also required very special instruction, with courses and instructors for all flyers through the various stages of their progress, for the receiving force on the ground, and for the men responsible for the upkeep of the radio equipment. At the outset, volunteer civilians, each with his own methods of instruction, stepped into the breach, but by the end of the year two radio officers, and four enlisted men’s schools were in operation with 49 and 329 graduates, respectively; radio officers and equipment had been sent to every field and ground school; and the courses for flyers had been standardized all the way through. Aerial photography, which had developed during the war into an exact science, required similar triple instruction—that for observers to operate the cameras in the air, intelligence officers on the ground to interpret them, and enlisted men to aid in the developing, printing, and enlarging, and to keep the equipment in condition. Where the United States had not even a single aerial camera at the outbreak of the war, by the end of the year there had been opened on March 25 a large school for developers and printers at Rochester, N. Y., with 680 graduates by June 30, an officers’ school on January 6 at Cornell teaching map compilation and interpretation, and photographic “huts” with complete personnel and equipment for instruction at each of the flying fields.