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The Signal Corps

A. W. Greely, Major-General, United States Army
No other arm of the military services during the Civil War excited a tithe of the curiosity and interest which surrounded the Signal Corps. To the onlooker, the messages of its waving flags, its winking lights and its rushing rockets were always mystic in their language, while their tenor was often fraught with thrilling import and productive of far-reaching effects.

The signal system, an American device, was tested first in border warfare against hostile Navajos; afterward the quick-witted soldiers of both the Federal and Confederate armies developed portable signaling to great advantage. The invention of a non-combatant, Surgeon A. J. Myer, it met with indifferent reception and evoked hostility in its early stages. When the stern actualities of war were realized, its evolution proceeded in the Federal army in face of corporation and departmental opposition, yet despite all adverse attacks it ultimately demonstrated its intrinsic merits. Denied a separate organization until the war neared its end, the corps suffered constantly from strife and dissension in Washington, its misfortunes culminating in the arbitrary removal of its first two chiefs. Thus its very existence was threatened. Nevertheless, the gallant, efficient services of its patriotic men and officers in the face of the foe were of such striking military value as to gain the confidence and win the commendation of the most distinguished generals.

Major Myer began work in 1861, at Georgetown, District of Columbia, with small details from the volunteers, though the [313]

Confederate signalmen in 1861 The Confederate signal service was first in the field. Beauregard's report acknowledges the aid rendered his army at Bull Run by Captain (afterwards General) E. P. Alexander, a former pupil of Major A. J. Myer. McDowell was then without signalmen, and so could not communicate regularly with Washington. While Major Myer was establishing a Federal signal training-school at Red Hill, such towers were rising along the already beleaguered Confederate coast. This one at Charleston, South Carolina, is swarming with young Confederate volunteers gazing out to sea in anticipation of the advent of the foe. They had not long to wait. During nearly four years the Union fleet locked them in their harbor. For all that time Fort Sumter and its neighbors defied the Union power.

[314] corps eventually numbered about three hundred officers and twenty-five hundred men. Authorized as a separate corps by the act of Congress, approved March 3, 1863, its organization was not completed until August, 1864. The outcome was an embodiment of the army aphorism that ‘one campaign in Washington is worth two in the field.’ More than two thousand signalmen served at the front, of whom only nine were commissioned in the new corps, while seventeen were appointed from civil life. As a result of degradation in rank, eleven detailed officers declined commissions or resigned after acceptance. Colonel Myer, the inventor and organizer of the service, had his commission vacated in July, 1864, and his successor, Colonel Nicodemus, was summarily dismissed six months later, the command then devolving on Colonel B. F. Fisher, who was never confirmed by the Senate. That a corps so harassed should constantly distinguish itself in the field is one of the many marvels of patriotism displayed by the American soldier.

Signal messages were sent by means of flags, torches, or lights, by combinations of three separate motions. The flag (or torch) was initially held upright: ‘ one ’ was indicated by waving the flag to the left and returning it from the ground to the upright position; ‘ two ’ by a similar motion to the right, and ‘ three ’ by a wave (or dip) to the front. Where a letter was composed of several figures, the motions were made in rapid succession without any pause. Letters were separated by a very brief pause, and words or sentences were distinguished by one or more dip motions to the front.

Signal alphabet, as used late in the war.

A—11G—1122M—2112S—121Y— 222
B—1221H— 211N— 22T— 1Z—1111
C— 212I— 2O— 12U— 221&—2222
D— 111J—2211P—2121V—2111tion—2221
E— 21K—1212Q—2122W—2212ing—1121
F—1112L— 112R— 122X—1211ed—1222


General Morell's lockout toward the Confederate lines—1861 When General McClellan was rapidly organizing his army from the mass of troops, distinguished only by regimental numerals, into brigades, divisions, and corps, in the fall and winter of 1861, General George W. Morell was placed in command of the first brigade of the Army of the Potomac and stationed at the extreme front of Minor's Hill, Virginia, just south of Washington. The city was distraught with apprehension, and the lookout, or tower, in the foreground was erected especially for the purpose of observations toward the Confederate lines, then in the direction of Manassas. At the particular moment when this picture was taken, the lookout has undoubtedly shouted some observation to General Morell, who stands with his finger pointing toward the south, the Confederate position. That the army has not yet advanced is made evident by the fact that a lady is present, dressed in the fashion of the day.



1—12221=Wait a moment.

2—21112=Are you ready?

3—11211=I am ready.

4—11121=Use short pole and small flag.

5—11112=Use long pole and large flag.

6—21111=Work faster.

7—22111=Did you understand?

8—22221=Use white flag.

9—22122=Use black flag.

0—11111=Use red flag.


Code signals.

3 = ‘ End of word.’ 33=‘ End of sentence.’ 333=‘ End of message.’ 121212 = ‘ Error.’ 11, 11, 11, 3 =‘ Message received (or understood).’ 11, 11, 11, 3 =‘ Cease signaling.’ Constant and unbroken waving =‘ Attention, look for signals.’

To hasten work there were many abbreviations, such as: A = ‘After’; B = ‘Before ’; C = ‘Can ’; Imy = ‘Immediately’; N = ‘Not’; Q = ‘Quiet’; R = ‘Are’; U = ‘You’ and Y = ‘Why.’


When using Coston signals there were more than twenty combinations of colored lights which permitted an extended system of prearranged signals. White rockets (or bombs)= one; red=two, and green=three. White flags with a square red center were most frequently employed for signaling purposes, though when snow was on the ground a black flag was used, and with varying backgrounds the red flag with a white center could be seen at greater distances than the white.

To secure secrecy all important messages were enciphered by means of a cipher disk. Two concentric disks, of unequal size and revolving on a central pivot, were divided along their outer edges into thirty equal compartments. The inner and smaller disk contained in its compartments letters, terminations, and word-pauses, while the outer, larger disk contained [317]

At Yorktown.

Skilled Union signal parties were available for the Peninsular campaign of 1862, where they rendered invaluable service to McClellan. Work strictly for the army was supplemented by placing signal officers with the navy, and thus ensuring that cooperation so vitally essential to success. The victory of Franklin's command at West Point, after the evacuation of Yorktown, was largely due to the efficiency of the Signal Corps. Vigorously attacked by an unknown force, Franklin ordered his signal officer to call up the fleet just appearing down the river. A keen-sighted signal officer was alert on the gunboat, and in a few minutes Franklin's request that the woods be shelled was thoroughly carried out. This photograph shows the location of Union Battery No. 1 on the left, in the peach-orchard, at Yorktown, and the York River lies at hand, to the right of the house.

A lookout on the roof of Farenholt's house, Yorktown


Army and navy

These quarters were established near Harrison's Landing, Virginia, in July, 1862, after the ‘Seven Days’ battles during McClellan's retreat. Colonel (then Lieutenant) Benjamin F. Fisher, of the Signal Corps, then in command, opened a local station on the famous Berkely mansion. The Signal Corps had proved indispensable to the success of McClellan in changing his base from York River to James River. When the vigorous Confederate attack at Malvern Hill threatened the rout of the army, McClellan was aboard the gunboat Galena, whose army signal officer informed him of the situation through messages flagged from the shore. Through information from the signal officers directing the fire of the fleet, he was aided in repelling the advances of the Confederates. The messages ran like this: ‘ Fire one mile to the right. Fire low into the woods near the shore.’

Signal Corps headquarters in August, 1862

[318] groups of signal numbers to be sent. Sometimes this arrangement was changed and letters were on the outer disks and the numbers on the inner. By the use of prearranged keys, and through their frequent interchange, the secrecy of messages thus enciphered was almost absolutely ensured.

In every important campaign and on every bloody ground, the red flags of the Signal Corps flaunted defiantly at the forefront, speeding stirring orders of advance, conveying warnings of impending danger, and sending sullen suggestions of defeat. They were seen on the advanced lines of

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