The position is with the flag or other appliance held vertically, the signalman directly facing station with which it is desired to communicate. The "dot" is to the right of sender, embracing an arc of 90°, starting with the vertical and returning to it. The "dash" is a similar motion to left. "Front" is downward directly in front and instantly returned to vertical; it indicates a pause or conclusion. [Illustration: CONVENTIONAL FLAG SIGNALS] For communication between the firing line and the reserve or commander in rear, the subjoined signals (Signal Corps codes) are prescribed and should be memorized. In transmission, their concealment from the enemy's view should be insured. In the absence of signal flags, the head dress or other substitute may be used. Letter of If signaled from the If signaled from the Alphabet rear to the firing line firing line to the rear A M Ammunition going forward Ammunition required C C C Charge (mandatory at all Am about to charge if no times) instructions to the contrary C F Cease firing Cease firing D T Double time or "rush" Double time or "rush" or hurry F Commence firing Commence firing F L Artillery fire is causing Artillery fire is causing us losses us losses G Move forward Preparing to move forward H H H Halt Halt K Negative Negative L T Left Left O What is the (R. N., etc.?) What is the (R. N., etc.?) (Ardois and Interrogatory Interrogatory semaphore only) . . - - . . What is the (R. N., etc.?) What is the (R. N., etc.?) (All methods Interrogatory Interrogatory but ardois and semaphore) P Affirmative Affirmative R Acknowledgment Acknowledgment R N Range Range R T Right Right S S S Support going forward Support needed T Target Target [Illustration: TWO-ARM SEMAPHORE CODE] ARM SIGNALS The following arm signals are prescribed. In making signals either arm may be used. Officers who receive signals on the firing line "repeat back" at once to prevent misunderstanding. [Illustration: Forward] Forward, MARCH. Carry the hand to the shoulder; straighten and hold the arm horizontally, thrusting it in the direction of march. This signal is also used to execute quick time from double time.