KANTTAL FOR NONCOMMISSIONED OFFICERS. 831 



The elements of a letter should be slightly longer than in 

 sound signals. 



27. To call a station, make its call letter until acknowledged. 



28. If the call letter of a station be unknown, signal A until 

 acknowledged. Each station will then turn on a steady flash 

 and adjust. When adjustment is satisfactory to the called 

 station, it will cut off its flash and the calling station will 

 proceed with its message. 



23. If the receiver sees that the sender's mirror or light 

 needs adjustment, he will turn on a steady flash until an- 

 swered by a steady flash. When the adjustment is satisfac- 

 tory the receiver will cut off his flash and the sender will 

 resume his message. 



30. To break the sending station for other purposes, turn on 

 a steady flash. 



SOUND SIGNALS. 



56. Sound signals made by the whistle, foghorn, bugle, 

 trumpet, and drum may vrell be used in a fog, mist, falling 

 snow, or at night. They may be used with the dot and dash 

 code. 



In applying the General Service Code to whistle, foghorn, 

 bugle, or trumpet, one short blast indicates a dot and one long 

 blast a dash. With the drum, one tap indicates a dot and two 

 taps in rapid succession a dash. Although these signals can 

 be used with a dot and dasli code, they should be so used in 

 connection with a preconcerted or conventional code. 



Signaling by Two-Arm Semaphore. 



HAND FLAGS. 



43. Signaling by the two-arm semaphore is the most rapid 

 mc'tliod of sending spelled-out messages. It is, however, very 

 liable to error if the motions are slurred over or run together 

 in an attempt to make speed. Both arms should move ra]>idly 

 and simultaneously, but there should be a perceptible pause at 

 the end of each letter before making the movements for the 

 next letter. Rapidity is secondary to accuracy. For alphabet 

 see pages following. 



