CHAPTER II
SERVICE, CORPS AND RANK
The armed forces of the United States of America provided by the statute law of the land pursuant to the provisions of the Constitution are embraced within two grand divisions, the land forces and the sea forces, under the supreme command of the President as Commander-in-Chief.
These two grand divisions are subdivided into various services according to the duties required of them and the laws establishing and maintaining them.
The Land Forces.—The land forces of the United States are made up of the regular army or as it is sometimes called the “standing army,” the organized land militia when called into the service of the United States which is practically the same as the so-called national guards of the several states, and such volunteers and drafted men as may be authorized by the Congress from time to time as occasion demands.
In times of peace the Army consists of the regular army, but in case of an invasion or threatened invasion of the territory of the United States or of rebellion or threatened war against the constituted government of the nation, this force may be augmented by calling the organized militia into service and further augmented if necessary by the employment of volunteers or drafted men, with the authorization of the Congress.
The land forces, however raised, are also divided into the Mobile Army and the Coast Artillery. The mobile army is intended for active offensive operations against the enemy and is so called on account of the fact that for its duties it requires the greatest degree of mobility possible, while the coast artillery is intended to man and fight the fixed and movable elements of land and coast fortifications including land mines, submarine mines and torpedo defenses pertaining to the fortifications.
These two groups frequently assist each other, the mobile forces protecting the flanks and approaches to the fixed defenses, and the latter being used as turning points or supporting points to the lines of the mobile forces.
The Army is divided into various arms or corps according to the duties required, as follows: infantry, cavalry, field artillery, coast artillery corps, engineer corps, signal corps including aviation section, quartermaster corps, ordnance corps, judge advocate’s corps, inspector general’s corps and medical corps. Each of these arms or corps has a distinctive badge to be worn on all uniforms and a distinctive color for the facings and trimmings of dress uniforms, as described and illustrated in [Chapter IV].