1860 ~ 1865


Flags, Lanterns, Rockets and Wires:
Signalling in the American Civil War

~ By ~

Lieutenant Colonel Iain Standen
British Army, Royal Corps of Signals.

A number of other visual communication techniques were also tried and used during the Civil War. 

The first of these were coloured rockets, or Coston Signals (after inventor Martha Coston).  These were used for communicating in poor weather conditions, at sea or at night.  By applying short phrases to combinations of rockets, for example:

  • White = one
  • Red = two
  • Green = three etc..

        A formal message could be sent.

CLICK HERE for the SCA ~ Night Signals Coston Flares Page

Clearly signal stations on hills using visual signals, be they flags, lantern or rockets, could not only be seen by neighbouring stations but also by other troops, especially the enemy.  With such a potential intelligence bonanza so readily available, Signal Corps personnel spent much of their time watching each others stations, noting down the ‘flag signals’, and then decoding the communications.  The examples of this intelligence battle are numerous.  One member of the US Signal Corps reported:

“I am daily reading the enemy’s signals & get much good information. [6]

Whilst during the Bermuda Hundred expedition a Union station provided a superb view of three enemy signal stations, so a regular watch was established over them for just that purpose.  And in operations around Charleston in 1863 the Confederates employed seventy-six signalmen, twelve of whom did nothing but read enemy messages.  Indeed, although it is difficult to estimate exactly how much of their work was spent intercepting the enemy’s signals, the respective Signal Corps must have spent significant amounts of time doing just that.  This suggestion is well supported by the Official Records, which, if they are an accurate indicator, teem with reports of intercepted Signal Corps Messages.

Cipher Disk

In order to counter this, both Signal Corps developed ciphers to encode the information they sent.  Myer himself invented a cipher wheel that allowed a message to be encoded and decoded quickly by sending and receiving stations.  The cipher disk consisted on two concentric disks of unequal size that revolved on a central spindle and were divided into thirty equal compartments.  The smaller inner disk contained in its compartments letters, terminations and pauses, whilst the outer disk contained groups of signal numbers to be sent.  A pre-arranged key was then used to align the disks and messaged could be encoded or decoded.  This proved a very successful and provided a high degree of security. 

The Confederates too had a cipher system, called by the Confederate War Department the ‘Court Cipher or Vigenere’ .  This was a letter substitution code dating back to the 1500s when it had been employed in palace intrigues and inter-state diplomacy during the rise of Europe's modern states. The key points of this cipher are the table and the key.  There was also an automated decoding machine invented to speed the process.

The final communications method I wish to look at is the Telegraph.  At the time this was probably the most significant technological development in the military communications.  It was not of course developed during the Civil War and had been used commercially before.  However, it required considerable skill to operate because to send messages required the use of Morse Code (which has been invented in 1838).  Myer was quick to appreciate the potential of the telegraph and as early as June 1861 was lobbying the Secretary of War for the Signal Officer of the Army to be responsible for the, and I quote:

’…telegraphic duty of the army, whether such signal duty is performed by means of signals transmitted by electricity or by aerial signals.’[7]

Myer gained considerable support for his case and as the Union Army recovered from the disaster of First Manassas, Myer again wrote to the Secretary of War:

        ‘I propose with your permission to organize a telegraph signal train to accompany the army on its march. The wagons of the train to carry all articles needed for temporary telegraphic uses in the field; that is, apparatus and supplies for the use of both electric and aerial telegraphs, rockets and composition night signals, carefully prepared, packed, numbered and arranged for instant use.

        It is proposed to carry on the train four flying field telegraphs, the train to be accompanied by, and in charge of, suitable officers and men, to each of whom his duties shall be assigned, and of whom a proper proportion shall be selected telegraphists, who shall be instructed also in the use of the telegraphic and flag signals, and who, employed for the war, shall be sworn to a faithful discharge of their duties.”[8]

This plan met with considerable support in the higher echelons, particular proponents being General George McClellan and General Irvin McDowall, with the final seal of approval coming from the General-in-Chief Winfield Scott who fowarded Myer’s proposal to the Secretary of War.  Unfortunately as so often happens in the military when trying to establish new ideas and capabilities, the in built caution and prejudice of the system resulted in the idea receiving a very lukewarm reception.  As a result when an order was issued on 14th August 1861 from the Secretary of War’s office in which the requirements for the performance of signal duties was laid down, it included following, rather non-committal paragraph, on the telegraph:

        “Should you find it necessary, you are authorised to purchase a small telegraph train to aid you to communicate with those points which cannot be reached by signals, to be paid for out of the telegraphic fund. [9]

Although this order neither formally agreed, or refused, Myer permission to create a military telegraph, it did infer some form of permission.  However, what it did not authorise was the money to do anything substantive.  Nonetheless Myer set about organizing his mobile or ‘flying telegraph’ the aspiration being to:

        ‘…To have with the Army of the Potomac the apparatus for establishing at any time a temporary telegraph line of the length of twenty miles.  For this purpose there were to be four flying telegraphs, four double reels, each reel to carry three miles of insulated wire; instruments and batteries to be attached to the reels; each flying telegraph to be accompanied by three operators.’ [10]

In theory such a train could lay 10 miles of wire in four hours and would have provided a significant enhancement to the capability of the Union Army.  However, Myer was faced with two significant problems.  First the existing telegraph equipment required the transporting of large batteries to power the lines.  Second he required skilled telegraphists to operate the equipment.  Myer therefore wanted to find a way of simplifying the process of sending telegraph messages and he thought he had found the solution in the Beardslee Telegraph machine.  Invented in 1862 by Mr GW Beardslee of New York, the Beardslee Telegraph appeared to be the answer to Myer's prayers.

The principal advantages of the Beardslees were that it could be operate without batteries and by men without knowledge of Morse code.  The key to the Beardslee was that it operated using magnetos.  These generated the power to send electricity over the telegraph wire.  In theory, the operator need only to move the lever to a point on the dial representing the ‘letter’ he wishes to send as part of his message.  On the receiving end, the pointer would move to the corresponding position on the dial.  Thus, the information is sent exactly as it was meant to be sent and, theoretically, without error.  The operator need only copy down the characters he saw "dialed".

2nd Manassas Telegraph Lines

Myer received his first Beardslees in May 1862 and they were deployed in the Second Manassas campaign and at Fredericksburg that winter, which this map demonstrates.  Here you can see a network that links together Burnsides’ HQ at Phillips House with the commanders of the two of the grand divisions: Sumner with his HQ at the Delacy House, and Franklin with his HQ across the river.  It also provided a rear link to the Army’s depots on the Potomac River.  Unfortunately for Major Myer, when operating under the pressure of real-time operations the Beardslee wasn't as promising as many had hoped.  The machine required lots of maintenance, didn't send signals as far as battery powered devices, and the device did not endear itself to the professional telegraphic community. 

The technical limitations of the Beardslee can be broadly broken down as follows:

        ·         A slow rate of transmission

        ·         An error rate considered to be higher than the magnetic telegraph

        ·         A very limited transmission range.

In truth, these are all inter-related to a high degree.  Although in theory the Beardslee was simple to operate in practice it was very different.  The operators had to do more than just turn the lever to the correct character on the dial.  There was a whole set of steps and procedures for the operation of the machine.  Additionally there was a set of procedures which had to be followed by all Beardslee operators along a given telegraph circuit in order for messages to be sent.  To many operators the Beardslee, was complicated and not as easy to learn as promised.  Among many, it was considered an "expensive failure".  Repeatedly, it was demonstrated that trained operators using a conventional telegraph system could send messages faster than most, if not all, operators using a Beardslee machine.  This is due, in part, to the fact that the Beardslee was never allowed to mature.  Operators never gained a similar familiarity with its operation as did the conventional telegraph operators with their telegraph equipment.

USMT worker stringing wire

At this stage we must bring in the other organization within the Union which was also operating in this field in parallel to the Signal Corp’s telegraph capability – The United States Military Telegraph or USMT.  The USMT was a civilian organization, (Picture right, shows one at work) which initially provided only medium and long-range telegraphic communications.  The USMT was developed to operate existing commercial lines and to build new ones as demand grew.  It utilised Morse’s system and although technically under the Quartermaster General’s command, the Secretary of War, Stanton, effectively exercised direct control over it. Anson Stager, the pre-war general superintendent of the Western Union Company, headed the organization, with his principal assistants being Thomas T. Eckert in the East and Robert C. Clowry in the West.

Both Myer and Stager realised that the distinction between battlefield telegraphy transmitted by the Signal Corps and longer-range telegraphic messages made little sense.  The result was a battle over roles and missions, with each man laying claim to all telegraphic communications.  Resolving the conflict became urgent in mid-1863 when, after the Beardlee machines had consistently malfunctioned, Myer tried to convert to Morse Telegraphy, which meant raiding the USMT’s personnel and logistical support.  The climax came in November 1863 when Stanton ordered Myer to an obscure job in Cairo, Illinois, and in War Department, Adjutant-General’s Office, Special Order 499 dated 10 November 1863, directed that the Signal Corps to surrender its field telegraph equipment to Stager and the USMT.  From then on the Signal Corps employed visual signals only and the USMT never used the Beardslee machines, relying instead upon the Morse system for all telegraphy.  The picture below, shows one of the USMT’s telegraph wagons.

USMT telegraph wagon

Throughout the period War Secretary Stanton was a staunch supporter of the USMT and writing in his annual report at the end of 1863 said:

        ‘The military telegraph, under the general direction of Colonel Stager and Major Eckert, has been of inestimable value to the service and no corps has surpassed - few have equalled - the telegraph-operators in diligence and devotion to their duties’[11]

Nonetheless the key point here is that functions of the Signal Corps and the USMT were for the most part very different.  The USMT handled logistic, operational and strategic communications, whereas the Signal Corps operated at the tactical and, occasionally at the operational level.  The latter’s tactical employment was very evident at Fredricksburg and Chancellorsville where the field telegraph was widely deployed.  However, it was when claim was made to blend the functions that the conflicts flared up.

Pocket Telegraph

In the west these functions were sharper and clearer over the vast distances concerned.  The telegraph stretched forward and backward in the operational movement of Sherman as he executed his march to the sea.  Indeed he was great fan of the telegraph and even owned his own pocket telegraph set such as the one shown here.  At the same time across that forty mile wide front the flags and torches of the Signal Corps performed, much the same as did the Confederate Signal Service, gathering information and co-ordinating the widespread units. 

At the same time in the east, the US Signal Corps was relegated to observation while the United States Military Telegraph operated, at times, right down to the Brigade level.  This was the time of Petersburg and trench warfare.  In a twist of irony, when the war ended, the civilian's who ran the USMT decided that they wanted nothing to do with the telegraph lines needed by the military ‘out west’ and the service was turned over to the Signal Corps.  Much of this had to do with the lack of the ability of the USMT "brass" to make money speculating on events in the west.

By the end of 1863 the USMT had created a network linking Washington to various army headquarters.  From there temporary field lines snaked forward to corps and division headquarters, and in some cases even to advanced field works, Signal Corps stations, and picket lines.  By April 1862 some 3,700 miles were in operation with another 1,800 by April 1863, another 3,700 by April 1864, another 3,300 by April 1865.  When an army advanced telegraphic communications moved apace, to the marvel of commanding officers.  It has even been reported that at times telegraphers even extended their operations into enemy lines during the heat of battle.  (Whether this was deliberate or as a result of the fog of war is unclear!) Through this means (which was relatively impervious to atmospheric conditions and weather), generals directed the movement of their armies.  They could synchronise advances (or retreats) and logistic support, learn about enemy activity and dispatched reinforcements.  The number of telegrams indicates how heavily the Union armies relied upon the USMT.  For the year ending 30 June 1863 Stager reported that the USMT had sent and received 1.2 million messages ranging in length from ten to more than a thousand words.  During the war the daily average of military and government telegrams was 4,500.  By the end of the war it was estimated that 6.5 million Union messages were sent at the cost of 40 cents per message!

PART I        PART II         PART III

[6]               US Army Intelligence History: A Sourcebook page 40.

[7]               Brown, page 171.

[8]               Ibid, page 172.

[9]               Ibid, page 172.

[10]             Ibid, page 173.

[11]             Lincoln in the Telegraph Office, David Homer Bates, Bison, 1995 page 11.

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