Camp Devens - Signaling Training - WW1 Cantonment 1918
The knowledge of the methods of signaling is not restricted to the Signal Corps, but is necessary to men in every branch of the service. The two principal codes used by the United States army are the wig-wag, which is a visual adaptation of the International Morse code, and the semaphore two-arm or two-flag code, which is illustrated in the accompanying picture.
Certain movements and formations are also regulated by signals, the knowledge of which is imperative to their proper execution. Often in the trenches or on the battlefield, the noise or distance is so great that oral communication is impossible, and written notification not feasible. On this account it is absolutely necessary that the soldier, whether engineer, cavalryman or artilleryman, be able to communicate with his officers or companions in another part of the field by arm signals.
Ordinarily, flags are used, as they are more easily seen, but in this picture where the training is taking place, they are not necessary, and only two men seem to be equipped with them. The semaphore code is very simple and the letters follow certain movements of the arms in logical sequence. The man in front is signaling the letter 0. Of the three men on the right whose arms are raised, the first is giving the letter J, and those behind him are both signaling the letter A. The signalers are members of the 14th and 15th Companies of the Depot Brigade.