(_b_) The purpose of _extended order drill_ is to teach the _mechanism_ of deployment, of the firings, and, in general, of the employment of troops in combat. Such drills are in the nature of disciplinary exercises and should be frequent, thorough, and exact in order to habituate men to the firm control of their leaders. Extended order drill is executed _at ease_. The company is the largest unit which executes extended order drill. (_c_) _Field exercises_ are for instruction in the duties incident to campaign. Assumed situations are employed. Each exercise should conclude with a discussion, on the ground, of the exercise and principles involved. (_d_) The _combat exercise, a form of field exercise_ of the company, battalion, and larger units, consists of the _application of tactical principles_ to assumed situations, employing in the execution the appropriate formations and movements of close and extended order. Combat exercises must simulate, as far as possible, the battle conditions assumed. In order to familiarize both officers and men with such conditions, companies and battalions will frequently be consolidated to provide war-strength organizations. Officers and noncommissioned officers not required to complete the full quota of the units participating are assigned as observers or umpires. The firing line can rarely be controlled by the voice alone; thorough training to insure the proper use of prescribed signals is necessary. The exercise should be followed by a brief drill at attention in order to restore smartness and control. 7. In field exercises the enemy is said to be _imaginary_ when his position and force are merely assumed; _outlined_ when his position and force are indicated by a few men; _represented_ when a body of troop acts as such. _General Rules for Drills and Formations._ 8. When the _preparatory_ command consists of more than one part, its elements are arranged as follows: (1) For movements to be executed successively by the subdivisions or elements of an organization: (_a_) Description of the movement; (_b_) how executed, or on what element executed. (2) For movements to be executed simultaneously by the subdivisions of an organization: (_a_) The designation of the subdivisions; (_b_) the movement to be executed. 9. Movements that may be executed toward either flank are explained as toward but one flank, it being necessary to substitute the word "left" for "right," and the reverse, to have the explanation of the corresponding movement toward the other flank. The commands are given for the execution of the movements toward either flank. The substitute word of the command is placed within parentheses. 10. Any movement may be executed either from the halt or when marching, unless otherwise prescribed. If at a halt, the command for movements involving marching need not be prefaced by _forward_, as 1. _Column right (left)_, 2. _MARCH_. 11. Any movement not specially excepted may be executed in double time.