John D. Billings, Hardtack and Coffee: The Unwritten Story of Army Life

Plate 1 represents a member of the Signal Corps in position, holding the flag directly above his head, the staff vertical, and grasped by both hands. This is the position from which all the motions were made.

Plate 2 represents the flagman making the numeral “2” or the letter “i.” This was done by waving the flag to the right and instantly returning it to a vertical position. To make “1” the flag was waved to the left, and instantly returned as before. See plate 3. This the code translated as the letter “t” and the word “the.” “5” was made by waving the flag directly to the front, and returning at once to the vertical.

The signal code most commonly used included but two symbols, which made it simple to use. With these, not only could all the letters of the alphabet and the numerals be communicated, but an endless variety of syllables, words, phrases, and statements besides. As a matter of fact, however, it contained several thousand combinations of numerals with the significance of each combination attached to it. Let me illustrate still further by using the symbols “2” and “1.”

Let us suppose the flagman to make the signal for “1,” and follow it immediately with the motion for “2.” This would naturally be read as 12, which the code showed to mean O. Similarly, two consecutive waves to the right, or 22, represented the letter N. Three waves to the right and one to the left, or 2221, stood for the syllable tion. So by repeating the symbols and changing the combinations we might have, for example, 2122, meaning the enemy are advancing; or 1122, the cavalry have halted; or 12211, three guns in position; or 1112, two miles to the left,--all of which would appear in the code.

Let us join a signal party for the sake of observing the method of communicating a message. Such a party, if complete, was composed of three persons, viz., the signal officer (commissioned) in charge, with a telescope and fieldglass;