The Wig Wag
The oldest flag system associated with the US Army Signal Corps is called Wig-wag. The name reflects the concept of back and forth movement as a means of signaling through motion. (PLEASE NOTE: Often this system has been misidentified as “Wig-wam.” A Wig-wam is a temporary arched framework structure overlaid with bark or hides to provide shelter used by Native Americans of the Algonquian language group.) Wig-wag is the signaling system developed for military field operations by Army surgeon Albert J. Myer prior to the Civil War. He developed this system based on a two element “tap-code” he created for the deaf. Myers’ Wig-wag system uses one flag for signaling. The position of the flags, left, right, front, represent the numerals 1, 2, 3 respectively and combinations of these numerals are used to convey the message.
The one-flag Wig-wag system used a cotton flag of two, four, or six feet square. The larger the flag, the greater distance it could be seen. The flag pole could be extended to a length of 16 feet using 4-foot segments joined with brass fittings. It took a strong soldier to wave a 16 foot pole with a 6-foot square flag on it for an hour or more, especially in wind, heat and probably under enemy fire. During night operations, the flag was replaced with a specially designed kerosene fueled torch, but employed exactly as the flag would be during daytime. During daytime operations, different sizes and colors of flags were employed based upon atmospheric conditions, such as clouds, haze, blue sky, etc. The signal soldier had these varieties of flags as part of their kit, but at any one time, only one flag or torch was used for signaling.
The Myer Wig-wag system and associated codes were used by both Union and Confederate armies during the Civil War. The Union Navy also employed this system and it served as the first Joint Signal Code between the Army and Navy until the end of the nineteenth century.
To summarize, the Wig-wag system used one flag or one torch for operations. If you are a Signal soldier, do not call it Wig-wam as your branch founder Albert J. Myer would not be happy with you.
General Service Code*
.*The flag movements were the reverse of those in Myer's original code, i.e., a movement to the right indicated "1" and to the left, "2." The movement of the flag to the front of the the flagman indicated the numeral "3." The Army continued to use the General Service Code until 1912.
Find out more in "Getting the Message Through" at http://www.history.army.mil/books/30-17/Front.htm#toc