Signal Corps in the American Civil War The Signal Corps in the American Civil War comprised two organizations : the U . S . Army Signal Corps , which began with the appointment of Major Albert J . Myer as its first signal officer just before the war and remains an entity to this day , and the Confederate States Army Signal Corps , a much smaller group of officers and men , using similar organizations and techniques as their Union opponents . Both accomplished tactical and strategic communications for the warring armies , including electromagnetic telegraphy and aerial telegraphy ( " wig - wag " signaling ) . Although both services had an implicit mission of battlefield observation , intelligence gathering , and artillery fire direction from their elevated signal stations , the Confederate Signal Corps also included an explicit espionage function . The Union Signal Corps , although effective on the battlefield , suffered from political disputes in Washington , D . C . , particularly in its rivalry with the civilian - led U . S . Military Telegraph Corps . Myer was relieved of his duties as chief signal officer by Secretary of War Edwin M . Stanton for his attempts to control all electromagnetic telegraphy within the Signal Corps . He was not restored to his role as chief signal officer until after the war . U . S . Army ( Union ) Signal Corps . First chief signal officer . The " father " of the U . S . Army Signal Corps was Major Albert J . Myer , an Army surgeon with an interest in communications by sign language for the deaf and then in signaling over long distances with lightweight and simple to use equipment . He invented a signaling system using a flag ( or a kerosene torch for nighttime use ) that is known as wig - wag signaling , or aerial telegraphy . Unlike semaphore flag signaling , which employed two flags , Signal wig - wag required only one , using a binary code to represent each letter of the alphabet or digit . Myer was serving at Fort Duncan , Texas , in 1856 when he wrote to Secretary of War Jefferson Davis and offered his signaling system to the War Department . Although the chief engineer of the Army , Colonel Joseph G . Totten , supported Myer ' s proposal , it did not include specific technical details and Davis rejected it . When John B . Floyd replaced Davis as secretary of war in 1857 , Totten reintroduced Myer ' s proposal , and in March 1859 , a board of examination was formed in Washington , D . C . The board , presided over by Lt . Col . Robert E . Lee , was not enthusiastic about the proposal , judging it suitable only as a secondary means of communications over short distances , but it did recommend further testing . Myer began testing in April 1859 at Fort Monroe , Virginia , and then New York Harbor , West Point , New York , and Washington , D . C . One of Myer ' s principal assistants was Second Lieutenant Edward Porter Alexander , the future Confederate signal , engineer , and artillery officer . They were able to communicate at distances up to 15 miles and Myer reported to the War Department that the tests had " exceeded anticipation . " He recommended that the Army adopt his signaling system and that he should be placed in charge of it . On March 29 , 1860 , the United States House of Representatives approved the Army appropriations bill for fiscal year 1861 , which included the following amendment : The United States Senate eventually approved the appropriations bill , over the objections of Jefferson Davis , now Senator from Mississippi , and President James Buchanan signed it into law on June 21 , 1860 , the date now celebrated as the birthday of the modern U . S . Army Signal Corps . Myer ' s appointment as the first signal officer with the rank of major was confirmed by the Senate on June 27 . However , the appropriations bill provided for no personnel to work for Myer and the Signal Corps as a formal organization would not be authorized until March 1863 . Immediately before the war , Myer was assigned to the Department of New Mexico to test his signals in the field during a campaign against the Navajos . In that assignment , he was assisted by Second Lieutenant William J . L . Nicodemus , who would later succeed him as chief signal officer . Field testing proceeded successfully , winning the admiration of Major Edward Canby , who became a strong advocate of forming a dedicated Signal Corps ; Myer at this time believed that the best approach for staffing signal work would be to train officers across the Army in its disciplines . War organization . Upon the outbreak of war , Myer returned to Washington and addressed the problem of having no signal personnel . His only option was to persuade officers to be detailed from other assignments , which was not considered satisfactory by Myer or the officers themselves , who feared loss of promotion opportunities . He submitted draft legislation to Secretary of War Simon Cameron in August 1861 , proposing that a Signal Corps be established with himself , seven assistant signal officers , 40 warrant officers , and 40 signal artificers to serve as line builders and repairmen . He intended that each division of the Army , which he assumed would eventually comprise 500 , 000 men , would have dedicated aerial and electromagnetic telegraphy support . Congress adjourned without considering the legislation . That fall , Myer , who in addition to being chief signal officer for the Army , served as chief signal officer of the newly formed Army of the Potomac , set up training facilities for detailed officers and men in Fort Monroe and at Red Hill , Georgetown , Washington , D . C . His latter training camp remained in operation through the Peninsula Campaign and the rest of 1862 , a period in which he continued to lobby with Congress and the Secretary of War , now Edwin M . Stanton , to establish a permanent corps . Myer ' s persistence paid off when President Abraham Lincoln signed a sundry civil appropriations bill on March 3 , 1863 , which authorized the organization of a Signal Corps during the " present rebellion . " It included the position of chief signal officer with the rank of colonel , a lieutenant colonel , two major s , a captain for each corps or military department , and as many lieutenants , not to exceed eight , per corps or department as the president deemed necessary . Each officer was provided one sergeant and six private s . Myer was appointed to the position of chief signal officer and the rank of colonel by Secretary Stanton on April 29 , but his appointment could not be immediately confirmed by the Senate , which was in recess . Although Myer interpreted his appointment to include control over electromagnetic telegraphy , a rival organization emerged . The U . S . Military Telegraph Corps employed civilian telegraph operators , with supervisors who received military commissions in the Quartermaster Department , under the general management of Anson Stager , a former official of the Western Union Telegraph Company . In February 1862 , Lincoln took control of the nation ' s commercial telegraph lines , which were then used by Stager ' s organization . Secretary Stanton , a former director and attorney for the Atlantic and Ohio Telegraph Company , understood the technical and strategic importance of telegraphy and located the telegraph office directly next to his own in the War Department . One of his biographers described the operators as Stanton ' s " little army . . . part of his own personal and confidential staff . " Myer began a campaign to supersede this organization by proposing the purchase of equipment to form telegraph trains ( in the sense of wagon trains , not railroad ) in the Signal Corps , to provide mobility for telegraph operators supporting armies on the move . Since he was concerned about the training required for telegraph operators using traditional Morse key equipment , he outfitted his trains with a magneto - electric telegraph instrument invented by George W . Beardslee of New York City . When this device suffered from technical limitations , in the autumn of 1862 he advertised in the " Army and Navy Official Gazette " for trained telegraphers . The War Department informed Myer that his actions were " irregular and improper " and he was removed as chief signal officer on November 10 , 1863 . All of the Beardslee devices were given to the Military Telegraph Service ( which never used them , due to unreliability ) and Myer was transferred to Memphis , Tennessee . His replacement as acting chief signal officer was Major William J . L . Nicodemus , his former apprentice . During his exile in the West , Myer ' s " A Manual of Signals : For the Use of Signal Officers in the Field " was published in 1864 , a work that would remain the basis of signal doctrine for many years . Nicodemus inherited an organization that had grown to approximately 200 officers and 1000 enlisted men . He also ran afoul of Secretary Stanton when the 1864 annual report for the Signal Corps was published because it revealed that the corps was able to read the enemy ' s signals . Stanton rightfully believed this to be a breach of security and he dismissed Nicodemus from the Army in December 1864 . The final chief signal officer during the war was Colonel Benjamin F . Fisher , former chief signal officer of the Army of the Potomac , who had been captured near Aldie , Virginia , in the Gettysburg Campaign and spent eight months in Libby Prison before escaping and returning to duty . The Signal Corps completed its wartime service and was dissolved in August 1865 . During its lifetime , 146 officers were commissioned in the corps or were offered commissions . There were 297 acting signal officers appointed , although some were for very brief periods . The total number of enlisted men who served during the war was about 2 , 500 . Albert Myer was eventually rescued from oblivion . In May 1864 , Myer ' s prewar ally , Edward Canby , selected him to be the signal officer for the Military Division of West Mississippi . Myer served in this position as a major because his confirmation as a colonel had been revoked after his dismissal from Washington . At the end of the Civil War , he was given a brevet promotion to brigadier general . On July 28 , 1866 , reacting to the influence of Lt . Gen . Ulysses S . Grant and President Andrew Johnson , Congress reorganized the Signal Corps and , with the permanent rank of colonel , Myer again became chief signal officer , as of October 30 , 1866 . His new duties included control of the telegraph service , resolving the dispute that had removed him from his position . Confederate Signal Corps . Edward P . Alexander , Myer ' s assistant in testing the wig - wag signaling system , resigned his U . S . Army commission on May 1 , 1861 , to join the Confederate Army as a captain of engineers . While organizing and training new recruits to form a Confederate signal service , he was ordered to report to Brig . Gen . P . G . T . Beauregard at Manassas Junction , Virginia . He became the chief engineer and signal officer of the ( Confederate ) Army of the Potomac on June 3 . After becoming the chief ordnance officer for the Army of Northern Virginia , Alexander retained his position as signal officer , but his other duties took precedence . Although the Confederate Signal Corps would never achieve a distinct branch identity to the extent that the Union version did , the Confederate Congress authorized its establishment as a separate organization , attached to the Adjutant and Inspector General ' s Department , on April 19 , 1862 , a year before the U . S . Congress did so . The first chief signal officer was Captain William Norris , a Maryland lawyer then a civilian volunteer on the staff of Maj . Gen . John B . Magruder . The corps under Norris was organized to consist of one major , 10 captains , 20 lieutenants , 20 sergeants , and 1500 men detailed from all branches of the service . A signal officer was authorized for the staff at each corps and division . The Confederate Signal Corps perform duties and utilized equipment very similar to their Northern counterparts , with some exceptions . Electric telegraphy was not used in tactical battlefield communications due to shortages of telegraph wire and trained operators . Their aerial telegraphy was performed with similar flags , but with slightly modified codes and movements from the Myer methods . Unlike the Union Signal Corps , however , the Confederate Signal Corps also was chartered to conduct espionage for the South . ( Both services provided valuable battlefield intelligence , and sometimes artillery fire direction , from their elevated observation points , but the Confederate corpsmen performed undercover missions behind enemy lines as well . ) Acting as the Secret Service of the Confederacy , the corps administered the Secret Line , an information network that ran between Richmond and the North and extended into Canada . It is because of its clandestine nature that much of the work of the Confederate Signal Corps is lost to history . Many of its records were burned in the fall of Richmond and in a subsequent fire at Norris ' s home , which claimed his personal papers . Signal equipment and techniques . Wig - wag signaling . Wig - wag signaling was performed during daylight with a single flag tied to a hickory staff constructed in four - foot jointed sections . Flags were generally made of cotton , linen , or another lightweight fabric and were issued in the following sizes : The 4 - foot flags with white backgrounds , mounted on 12 foot staffs , were most often used , although 2 - foot flags were used when the flagman wanted to avoid enemy attention . Red flags were generally used at sea . For nighttime signaling , torches were copper cylinders , 18 inches long and 1 . 5 inches in diameter with a cotton wick . Myer ' s " General Service Code " for wig - wag signaling , standardized in 1864 , was also known as the " four element " code because all of the characters transmitted were composed of from one to four flag motions . ( Myer ' s original method from the 1850s was called a " two element code " because elements were described only in terms of movement from the vertical position . ) The flagman took a position facing the station to receive the message and signaled digits " 1 " through " 5 " as follows : Codes for the alphabet , digits , and some special characters were as follows for the Union Signal Corps : Waving the flag continuously from left to right was used to attract attention and to indicate that signaling was about to start . Other special sequences of digits were : Telegraph train and the Beardslee telegraph . Telegraph trains were introduced by Myer to support telegraphy for mobile operations . The horse - drawn wagons carried the telegraph sets and supplies such as reels of insulated copper wire and iron lances , for stringing temporary field lines , a practice called " flying telegraph lines . " Each train consisted of two wagons , equipped with 5 miles of wire and a telegraph instrument . The first model train was constructed by Henry J . Rogers , a telegraphic engineer from New York City who had worked with Samuel F . B . Morse in building the first commercial telegraph line between Washington and Baltimore in 1844 . Rogers ' s original telegraph instrument for the train replaced the traditional sending key and sound receiver with a dial indicator , a circular index plate bearing the letters of the alphabet and a pointer that turned to the letter to be transmitted . A similar pointer spelled out the message at the receiving end . Rogers provided a galvanic battery that eliminated the danger of acid spills . This equipment eliminated the need for skilled operators who had to be trained in Morse code . Field trials in February 1862 found that it worked satisfactorily over a test circuit of 2 miles of wire . A board of three signal officers recommended that such a train would be of great use as an auxiliary to permanent telegraph lines . For its first use in combat , during the 1862 Peninsula Campaign , the Rogers train substituted a new telegraph instrument , the Beardslee Patent Magneto - Electric Field Telegraph Machine , invented by George W . Beardslee of New York . This instrument required no battery , using instead a hand - cranked generator , but it was also based on a dial indicator . The Beardslee telegraph was housed in a wooden chest with handles and weighed about 100 pounds . It had two significant technical deficiencies , however . Its generator could not produce enough electricity to transmit signals more than about 5 to 8 miles . More seriously , there was a tendency for the sending and receiving index pointers to get out of synchronization , hopelessly garbling transmitted messages . Broken machines had to be sent back to New York City for repair . It was these deficiencies that led Myer to his decision to use traditional Morse key technology and attempt to hire trained telegraphers , a decision that led Secretary Stanton to dismiss him as chief signal officer . All of the telegraph train assets of the Signal Corps were turned over to the Military Telegraph Service , but they did not use the Beardslee telegraph due to its unreliability . At their peak of usage in 1863 , there were 30 telegraph trains in the field . Ciphers . Since aerial telegraphy was sometimes conducted within the clear sight of the enemy , security was a major problem . The Signal Corps introduced a cipher disc , a simple device that allowed the encryption of text . Two concentric discs were inscribed with letters and their numerical equivalents . The sending and receiving party had to agree on the specific alignment between the two discs , ensuring that both parties had identical alignment . To encipher a message , the signal officer selected an " adjustment letter " on the inner disc and then made this letter correspond with a preselected numerical code or " key number " on the outer disc . The signal officer would typically give the key numbers to the flagmen without revealing the plain text version of the message . Although this method of encryption was primitive by modern standards , there is no record that the Confederates ever deciphered a Union message that had been processed in this manner . A more complex system in which four concentric discs were used was invented by Sergeant Francis M . Metcalf and modified by Captain Lemuel B . Norton , but it did not receive widespread adoption . Signal contributions to battles and campaigns . First Bull Run . At the First Battle of Bull Run , Confederate Capt . Edward Porter Alexander made history by transmitting the first message in combat using signal flags over a long distance . Stationed atop " Signal Hill " in Manassas , Alexander saw Union troop movements and signaled to the brigade under Col . Nathan " Shanks " Evans , " Look out for your left , your position is turned " , which meant that they were in danger of being attacked on their left flank . Upon receiving a similar message , Gens . Beauregard and Joseph E . Johnston sent timely reinforcements that turned the tide of battle in the Confederates ' favor . On the Union side , Albert Myer attempted to deploy a military observation balloon at Manassas , bringing along 20 troops from the 26th Pennsylvania Infantry because of the lack of Signal Corps personnel that early in the war . Because of the haste of these untrained men , the balloon was damaged after a collision with a tree and could not be used for the battle . Fredericksburg . At the Battle of Fredericksburg in December 1862 , significant use of the Beardslee telegraph made it possible for Maj . Gen . Ambrose E . Burnside to communicate with the Army through the fog and smoke from the burning town . On December 13 , the main day of the battle , signal corpsmen extended a line across the Rappahannock River into the town of Fredericksburg while under fire and Burnside was able to communicate with both of his grand division commanders and his supply base , 7 . 5 miles away . Chancellorsville . During the Battle of Chancellorsville in May 1863 , the performance of the Beardslee telegraph was so poor that Albert Myer soon decided to replace it . The campaign got off to a bad start because the chief signal officer of the Army of the Potomac , Captain Samuel T . Cushing , was kept in the dark about the plans of Maj . Gen . Joseph Hooker and he could not arrange his signal assets in advance . As the Army advanced , Cushing had insufficient wire on hand and was forced to use untested wire that had been left in the field , supported by iron lances , since Fredericksburg . On April 29 , as the Army prepared to cross the Rapidan River , the Beardslee telegraph did not work , probably due to excessive wire length . Captain Frederick E . Beardslee , son of the inventor , was sent to make repairs . He found that the machine had been hit by lightning and was operating erratically . That evening a telegraph reached headquarters from the Ford on the Rapidan at 10 : 30 p . m . , but it was marked ( incorrectly ) as originating at 5 : 30 p . m . Maj . Gen . Daniel Butterfield , Chief of Staff of the Army of the Potomac , told Cushing that he was not going to wake the commanding general for any telegram that was five hours late ; his repose was " worth more than the commissions of a dozen signal officers . " The inadequate wires and the unreliable telegraph caused persistent problems and kept General Hooker isolated from his forces in the Wilderness . On May 1 , operators of the U . S . Military Telegraph Service were ordered to replace the Signal Corps Beardslee operators . It was also at Chancellorsville that a major change happened in Union signal security . Butterfield was concerned about Confederate interception of aerial telegraphy signals , but he used this as an advantage , ordering deceptive messages to be transmitted early in the campaign to mask the Union Army ' s true intentions . Since the Union signal corpsmen could routinely decipher Confederate messages , Butterfield was able to confirm that his bogus messages had been received . It was after these incidents that the Union began deploying the cipher disc devices and improving the security of their messages . Gettysburg . The Battle of Gettysburg featured the Union Signal Corps in its role of observing the battlefield . The chief signal officer of the Army of the Potomac , Captain Lemuel B . Norton , had field telegraph trains at his disposal , but did not deploy them . On July 1 , 1863 , a Union signal officer , Lt . Aaron B . Jerome , ascended the cupola of the Lutheran Theological Seminary and the courthouse steeple to observe the enemy ' s approach and reported to Maj . Gen . Oliver O . Howard . On July 2 , the Confederate corps under Lt . Gen . James Longstreet attempted to maneuver into position for an attack on the Union left flank . They were forced into a lengthy counter march , delaying their attack , when they spotted the presence of the Union signal station on Little Round Top mountain and knew that their approach would be reported . During the Confederate assault , the fighting was so heavy that the signal station had to be abandoned until the following day . A plaque commemorating the U . S . Army Signal Corps ' contribution to the battle is mounted today on a boulder near the peak of Little Round Top . On July 3 , before Pickett ' s Charge , artillery fire against the Union line was so intense that the signalmen could not use their flags . Captain Edward C . Pierce , a signal officer attached to the VI Corps , acted as a mounted courier to Maj . Gen . George G . Meade ' s headquarters , despite warnings that he would never make it alive through the firing .