(_a_) Explain to the recruits the use of the horizontal clock system as a means of indicating directions. Inform them that they are, in this system, _always_ at the center of the dial. Call out various hours and require each recruit to extend his arm in the direction he understands is indicated. Explain and correct errors. Explain the use of the vertical clock system, impressing the recruits with the fact that in this system the _reference point_ is always at the center of dial. Call out an hour and require the recruit to name some object that is located on the hand of the clock at the designated hour. A diagram on paper may be of assistance. Explain and correct errors. Explain to the recruit that the angle subtended by the width of one finger at arm’s length from the eye and that subtended by the leaf of the rear sight to his rifle at 14 inches from the eye has a chord 50 yards long at 1,000 yards distance. The finger width and the sight leaf thus become known as units, and either may be used in indicating distances laterally. Having selected a reference point, name some object near it and require the recruit to tell you how many units (_fingers_ or _sight leafs_) apart they are. [Illustration: SKETCH SHOWING GERMAN FIXED RIFLE REST FOR FIRING THROUGH LOOP HOLES. (Captured at the Bluff.) NOTE.—Both lateral and horizontal movement is given and the rifle can be very firmly clamped when the required aim is found. ] CASE (B). [Illustration: HORIZONTAL CLOCK FACE SYSTEM (USED WHEN TARGETS ARE VISIBLE). ] ┌─────────────────────┬─────────────────────┬─────────────────────┐ │ SYSTEM. │ EXAMPLE. │ EXAMPLE. │ ├─────────────────────┼─────────────────────┼─────────────────────┤ │1. Announce direction│Target 2 o’clock │Target 11 o’clock. │ │2. Announce objective│A hostile patrol │A hostile patrol. │ │3. Announce range │Range 1,000 │Range 900. │ └─────────────────────┴─────────────────────┴─────────────────────┘ PROCEDURE. 1. All look along the line pointing toward the indicated o’clock of a horizontal clock face whose center is at the firing point and whose 12 o’clock mark is directly perpendicular to the firing line. 2. Look for the objective at— 3. A point on this line at a distance equal to the designated range. NOTE.—The clock here represented must be considered as horizontal, not vertical as shown. For the purpose of illustration perspective was not considered. The observer occupies the center of clock. CASE (C). [Illustration: VERTICAL CLOCK FACE SYSTEM (USED WHEN TARGETS ARE SMALL OR INDISTINCT). ]