Scope and Contents From the Series: Series I is divided into two parts, Part I is devoted to Military Intelligence and Part II is devoted to technical intelligence. Each part is arranged on different classification schemes.Series I, Part II contains approximately 30 linear feet of technical intelligence information. Each document in this part is classified by a four letter notation beginning with an X.Part II is organized on the following scheme of classification: Heading Subject XAD Administration XADM Administration - Military XADN Administration - Naval XAE Aeronautics XAEA Aeronautics - Airplanes XAEB Aeronautics - Balloons and Zeppelins ...