Wigwag (more formally, aerial telegraphy) is an historical form of flag signaling that passes messages by waving a single flag. It differs from flag semaphore in that it uses one flag rather than two, and the symbols for each letter are represented by the motion of the flag rather than its position. The larger flag and its motion allow messages to be read over greater distances than semaphore. Messages could be sent at night using torches instead of flags.
The most common code used with wigwag had three motions, only two of which were needed to form letters of the alphabet. These two were waving the flag, respectively, to the left and right – the wigwagging motion. A character was formed by sequentially displaying a number of motions (elements). Like Morse code, the number of elements in each character was not fixed, the most common letters being assigned the shortest codes. A number of other codes were used at times, some of them with a fixed number of elements and up to four different motions. Morse code was used with wigwag after it became an international standard.
The wigwag system was invented in the 1850s by US Army surgeon Albert J. Myer who became the first Chief Signal Officer of the US Army in command of the Signal Corps. Wigwag was used extensively by both sides in the American Civil War, where it was an essential adjunct to electrical telegraphy, and continued to see use in both America and Europe until the end of the century. After that, long-distance communication was performed by electrical telegraphy, or in some places where the telegraph was not available, by heliograph. This communication system was in use with the US Navy until the twentieth century.
Operation
The wigwag system consisted of a signalman waving a single large flag or other display device in different motions sequentially. At night, a lamp on a pole could be used, or over short distances the signalman might hold a small disk. The usual wigwag code was ternary, that is, there were three different motions (symbols) that could be displayed. However, only two of these symbols were used for letters, making it largely binary. The third symbol only appeared in control characters. The neutral position was the signalman holding the flag vertically and motionless above his head. The first motion was initiated by bringing the device downward on the signalman's right side and then quickly returning it to its upright position. The second motion brought the device down on the left side and then returned it to the starting position. The third motion lowered the device in front of the signalman, then restored it to its vertical position.Myer (1866), p. 83
Like Morse code, the normal wigwag code did not have a fixed length (number of elements) for each character. For instance, i was coded as "1", but d was coded as "222".Wolters, p. 10 The table shows the commonly used wigwag code and the diagram shows the flag motions.Myer (1872), p. 68 It is as defined in the General Service Code of July 1864 issued to standardize signals of the US Army and Navy.Raines, p. 13 Further details of the code and an alternate four-symbol representation are given in
+ Wigwag code (General Service Code)ABCDEFGHIJKLM22211212122212222122111221112221212211221NOPQRSTUVWXYZ11211212121121121221121222112121221112222
The notation of the wigwag code was originally defined as "1" representing the motion to the left and "2" representing the motion to the right. That is, all occurrences of "1" and "2" are interchanged in the table. This was changed when the General Service Code was issued. The thinking was that the motion to the left should be notated with the lowest digit, but as seen through a telescope (the usual method of observing) the image is inverted with left and right interchanged.Myer (1872), p. 95 The code tabulated in some modern sources shows this earlier notation with "1" and "2" interchanged.eg, Raines, p. 7
To open communication, the signalman waves the flag continuously from side to side (the "attention" signal) until the receiving station replies with the "understood" signal (22.22.22.3). The transmitting station replies with the "understood" signal and proceeds to send the message.Myer (1872), p. 72 The elements of a character are performed rapidly without pause between them, only returning the flag to the rest position at the end of the character. The US Army Manual of Signals lists several alternative codes, including a three-element fixed-length code using four symbols (1866 edition), and a three-element fixed-length code using three symbols (1872 edition). There is no indication in the manual that these codes were actually in use.
Wigwag has an advantage over flag semaphore in that only one flag is used instead of two.Raines, p. 5 Thus, both arms could be used to raise the flag and a larger, heavier flag could be employed. Nevertheless, signalmen required great strength to use a 4-foot flag on a 16-foot pole. Even a light wind would multiply the difficulty and rain made the flag heavier. Contemporary flags were heavier than modern equivalents, being made of linenMyer (1866), p. 176 or cotton. Modern large flags designed to be hand held might be made of lighter silk or nylon and are more resistant to moisture retention.Woods & Sterling, p. 159 Perhaps even more importantly, the signaling elements in wigwag consist of motions rather than positions as in flag semaphore. Motions are easier to distinguish than positions at great distances, thus giving wigwag a range advantage.
Flags and disks The flags came in seven combinations of colors and sizes. They were all square flags with a smaller square (one third the width) of a different color in the center. The colors available were a white flag with a red center, a black flag with a white center, and a red flag with a white center. All three were produced in the most commonly used four foot () size. The white and black flags came in a six-foot () size for greater range, and the white and red flags had a two-foot () size. The size and color of flag was chosen depending on lighting conditions and distance. The white flag was the most common and was used against dark backgrounds. Against light or varied backgrounds, the red flag was more effective and was also used at sea. The black flag was used against a background of snow.Greely, pp. 308–309 The two foot flags, called action flags, were used in situations where the signalman needed to stay under cover from enemy fire or wished to signal less obtrusively.Raines, p. 14 Each flag had a number of ties or tapes sewn along the hoist edge. These were used to fix the flag to a four-section staff, each section four feet long and fitted with ferrules for joining.Myer (1866), pp. 175–176
The disks were 12 to 18 inches (30 to 46 cm) in diameter and were made of metal or wood frames with canvas surfaces. Somewhat easier to handle than the heavy flags, they provided a different method for daylight communications. The lights were kerosene lanterns attached to a staff. A second "foot torch" was placed on the ground before the signalman as a fixed point of reference, making it easier for the recipient to follow the lantern's movements.Myer (1866), pp. 176–178 A 30X telescope was a standard part of the wigwag kit. This was used by a signaler alongside the flagman to read the signals from the remote station, which could be at a distance of up to 20 miles.Thompson, p. 12
History The wigwag system filled a gap in the history of military communication between the age of close-quarter fighting and the age of modern long-range weapons. In the 1860s, radio and telephone communications had yet to be invented and electrical telegraphy, although established, was still in its infancy. It was still being worked out how the latter could be used on the battlefield, and portable equipment ruggedized for military use was not available early in the decade. Wigwag provided a method that was both simple to use and faster and more reliable than couriers.Raines, p. 31 By the start of World War I, the range and accuracy of modern weapons had made flag signaling too dangerous to use on the front line, and more sophisticated technology was then available.Woods & Stirling, p. 160
Development
The wigwag system was invented by US Army surgeon Major Albert J. Myer in the 1850s. Myer took his inspiration from the telegraph code of Alexander Bain, although the codepoints finally used were not the same as Bain's. The Bain code, invented 1843, was used on the chemical printing telegraph of that inventor and was a dot-dash code similar to the Morse code. Myer came across it while working as a telegraph operator, work he did for a period after his graduation in 1847. In 1851, Myer produced A New Sign Language for Deaf Mutes as the thesis for his medical doctorate. In this publication Myer used the Bain code as the basis for communication with a deaf person by tapping a hand or cheek. Alternatively, tapping a table with which the person was also in contact could be used to pass messages. In 1854, Myer joined the army as an assistant surgeon and was posted to Texas. It was in Texas that he developed the idea of the wigwag flag or torch code for military use, building on his previous work with the deaf. Myer also incorporated features of Native American hand and smoke signals into his system.Wagner, p. 358
In 1856, while stationed at Fort Duncan, Texas, Myer wrote to Jefferson Davis, then Secretary of War, proposing his signaling system. He was supported by Joseph Gilbert Totten the Army Chief of Engineers but failed to get a hearing due to lack of detail in his proposal. In 1857, Totten tried again with a new Secretary of War, John B. Floyd. In 1859, a board of examination under Robert E. Lee considered the proposal but thought it had only limited use. They did not put it into operation but allowed Myer to continue with tests. Myer conducted these tests starting in April, initially at Fort Monroe, Virginia, and later in New York and Washington.Raines, p. 6
Myer, with Floyd's support, proposed that a new post of signal officer to the Army staff should be created, with him filling it. In February 1860, Myer got a hearing before the Senate Committee on Military Affairs under the chairmanship of Jefferson Davis which supported the introduction of the system. Davis opposed the creation of the signal officer post when it came before congress; he wanted to use the signaling system but feared the creation of the signal officer post would lead to the creation of a new department (the future Signal Corps). Davis's objections were ignored and Myer was made signal officer and promoted to major in June 1860.Raines, pp. 6–7 Myer submitted a patent application in 1860 claiming the rights to all signaling systems based on motions (of which wigwag is an example) as opposed to positions (of which flag semaphore is an example). The patent was granted in January 1861.Raines, pp. 7–8
In service
The first live use of the system was in 1860 in a campaign against the Navajo in the Department of New Mexico. Myer served under Major Edward Canby who became a strong supporter of the formation of a signal corps, which he thought more efficient than Myer's proposal to train every officer. The Navajo war was over by February 1861, but at the same time the American Civil War was beginning. Up to this point, Myer had been temporarily assigned men from the units in which he served to work as signalers, often grudgingly. This was impractical for a large scale war and Myer now pressed for Canby's idea of a dedicated signal corps. Many in Washington opposed the idea, and it took until 3 March 1863 before the Signal Corps was formally inaugurated, although the signalers had been informally called "signal corps" for some time. Myer was put in charge with the rank of Colonel.Raines, pp. 7–13
American Civil War