(1) General Staff Corps. (2) Adjutant General's Department. (3) Inspector General's Department. (4) Judge Advocate General's Department. (5) Quartermaster Corps. (6) Medical Department. (7) Ordnance Department. (8) Bureau of Insular Affairs. (9) Signal Corps. (10) Engineer Corps. The following are the grades of rank and commands of officers and noncommissioned officers: (1) General Commands: Armies. (2) Lieutenant-General Commands: Field Army. (3) Major-General Commands: Division. (4) Brigadier-General Commands: Brigade. (5) Colonel Commands: Regiment. (6) Lieutenant-Colonel Second in command in a Regiment. (7) Major Commands: Battalion. (8) Captain Commands: Company. (9) First Lieutenant Commands: Platoon. (10) Second Lieutenant Commands: Platoon. (11) Veterinarian He has no command. (12) Cadet at United States Military Academy He has no command. (13) Sergeant-Major (Regimental) He has no command. (14) Ordnance Sergeant He has no command. (15) Quartermaster Sergeant He has no command. (16) Sergeant-Major (Battalion) He has no command. (17) First Sergeant Commands: Platoon. (18) Sergeant Commands: Sometimes a Platoon. (19) Corporal Commands: Squad. ARTICLES OF WAR The Army is governed by the Articles of War, which can be found in the Army Regulations. Any laws, orders, et cetera, pertaining to the Army must not violate directly or indirectly any of the Articles of War. It is therefore desirable that each Reserve Officer know where to find them and become, in a general way, familiar with them. GENERAL ADVICE To become a first-class drillmaster is desirable and necessary. But, being one, you are not to be intrusted with the command of troops in the field unless you have gone much farther than that. To become an excellent drillmaster means simply that you have mastered a detail. In order to become one you should bear this in mind: You cannot teach a man how to do a thing unless you know that thing yourself. If you don't know your drill, don't try to "bluff" your men. Burn the midnight oil, or remain a private. MILITARY CORRESPONDENCE An official letter should refer to one subject only. In writing to the War Department address your letter to "The Adjutant General of the Army, Washington, D. C." The United States (including colonies) is divided into the following departments: (1) The Northeastern Department, with Headquarters at Boston, Massachusetts.