"A Manual of Signals: For The Use Of Signal Officers In The Field."
Washington, D.C., 1864.
"Signals of one element. --- Signals of this kind, are not much used for general purposes. Their employment is almost always to convey one or a few preconcerted messages. For signals of this class, one thing or indication is to be used, and it is not to be considered as varied, through it may seem to vary, in any signal. To mark the close of each complete signal, there must of course be a pause of time, or a pause-signal. A good illustration of signals of this kind, is found in the striking of a clock, when twelve different hours are indicated by the same and single sound, repeated the proper number of times to suit each hour. If in the striking of any hour, this sound varies so as to make two or three different notes even, this difference of sound effects, in no way, the meaning of the signal. Signals of this kind, may be used in the field, as where one rocket is thrown up to indicate any one message, two rockets a second message, three rockets a third message; and thus on to any given number.
Or a light may be shown a certain number of times, as a candle shown at a window, and then removed to stand for "one" or the first message; shown twice for "two," or the second message; three times for "three," or the third message; and thus on. Or, in a field or in a boat, a lantern may be kept lighted in a pail, and hoisted out of the pail and returned to it to make each flash. Or a lantern may be shown from behind a fence, or any kind of screen. In these illustrations, the appearance of the lights is the signal. Each complete signal may be shown by a wave of the light, or any other sign, as the pause-signal. Or guns may be fired the required number of times for any signal.
Now, in any of these signals, which are to depend upon the number of times a light is shown, or the number of times a gun is fired, no difference is, of course, made, if the light changes, or if there is difference of sound in different reports of the gun; for it is remembered only one element is used, and that the signal depends solely upon the number of repetitions of that element; for instance a white light shown twice, would stand for message number "two." A white light shown, and then a red light, making two in all, would also stand for "two." So the preconcert being that only one element is to be used in a set of signals, they may be made to seem much varied. Signals of one element, when used in the field are generally for instances as this: to fire two guns to indicate a completion of a military movement: to throw up three rockets, or one rocket; to announce that a portion of the army is to move. Of course several such messages can be arranged in one code.
Signals of Two Elements. --- The army code of signals, or rather the system of signals, used in the army; for there is no code, the letter signals changing often, sometimes, in a day, is of two elements. It will now, after the preceding instructions, be readily understood by this term that, whatever the devices adopted, or to whatever sense the signals may be addressed, or however complicated they may appear, the fact remains that, the signal exhibited, has in it no more than two elements, and if not a single signal is, when analyzed, only some arrangement of "ones" and "twos." Nearly all plans of signals of electric telegraphs, as used in Europe, are signals of two elements. The elements of the signals generally used in this country, are more numerous.
The systematizing of signals, using the bases of two elements, admits of such illimitable applications at once so much more simple and more numerous, than any other, that is seems best adapted to universal use. That signals could be made with two elements, has probably been known form very early antiquity by studies of the subject. The first systems recorded, seem to have been based upon this plan. To understand its practical use in the field, take an alphabet of two elements, devised by the given rule; as, for instance,
A is one, two, or 1 2.
B is one, two, two, one, or 1 2 2 1.
C is two, one, two or 2 1 2.
D is one, one, one 1 1 1;
and so on, combinations of "ones" and "twos."
To make day signals, there being furnished the regular set of signal Equipments, a flagman standing, holds in his hands a plain signal staff, eight or twelve feet long, having a signal flag attached at its upper extremity. There are one position and two motions. These are styled the First Position and the First or Second Motion. The first motion is whenthe flag is held vertically above the head of the flagman, the butt of the flag staff at the height of the waist, and grasped by both hands, the hands separated form each other about eighteen inches. The flag being in this position, the first motion is to wave the flag to the ground on the left-hand side of the flag-bearer, and to instantly return it to the first position. The second motion is to wave the flag to the ground on the right-hand side of the flagman, and instantly return it to the first position. The first motion is known for the signal "one," and is indicated by the numeral 1. The second motion is known for the signal "two," and is indicated by the numeral 2: these motions, ordered by the command, briskly given, "one," which causes the left hand motion; and "two" for the right hand motion. To make the signal 11 or "one-one," or "eleven," the flag being at the first position, the first motion is made, and instantly repeated, the flag then stopping at the first or vertical position. To make 11, or "one---one---one," or "one hundred and eleven," the first motion is thrice repeated. In this manner for any number of "ones" following each other.
To make 22, or "two---two," or "twenty-two," the flag being at the first position, the second motion is twice made; that is, the flag is waved quickly twice to the right. It then stops at the first, or vertical position. To make 222, or "two---two---two," or "two hundred and twenty two," the flag is waved three times to the right; then stopping at the first or vertical position; and thus for any number of "twos" following each other. To make 12, or "one---two," or "twelve," the flag being in the first position, the first motion is made, and is followed instantly by the second motion, without allowing the flag to pause at the vertical positions between the motions; that is, the flag is waved quickly once to the left ("one"), and without stopping, once to the right ("two").
On the completion of the second motion, the flags stops at the vertical position. To make 121, once to the left. It then stops. To make 1221, the flag is waved once to the left, twice to the right, and again to the left (left, right, right, left). All combinations of "one" and "two" are made in this manner. The flag must not be allowed to stop between the motions of any signals. When the flag stops in a vertical position, it indicates that a signal is completed; or this is the pause-signal. Thus a pause is made at the close of each letter-signal. The end of a word is indicated by waving the flag directly to the ground in front, and instantly bringing it again to the first position. This signal is called "three" or "five" or "front." To indicate a clause of a sentence, two "fronts" are made. To indicate the close of a message, three "fronts."
Signals by Two Elements may be reduced to the greatest simplicity for day uses. Thus, a handkerchief or hat held in the hand above the head, waved to the left for "one," to the right for "two," and lowered for "five," is legible. A handkerchief on a stick, or any white or light cloth tied to a gun may be used; or any cloth or any kind of a pole is apparatus sufficient. Or a man, standing fast, throws out his left foot for "one," and his right foot for "two," representing these proper numbers in succession. He drops both arms for the end of a word. Or, having a fixed place to start from, a man walks a pace or two to the left for "one," as many to the right for "two," and makes a sign at a fixed point to show the end of a word. Or, standing in view, a man touches any two things with a cane --- as a drum and a barrel. He touches the drum for "one," the barrel for "two." He waves the can to indicate the end of a word. Or men, places in line three or four at a time, may be made to represent letters. The men with coats on may be ones, those with their coats off "twos."
Strips of any kind of two-colored cloth may be sent up on the halyards of a common flag-staff, to represent any letter-signal or numeral-signal; and these can be arranged by being shown one after the other for messages; to be telegraphed in words; or for codes of message-signals by the rules before given.
Codes of signals, like the Naval flag-codes, may be thus prepared when masts or flag-staffs must be used; or, when it is desirable that a signal, as from an invested fort, should be hoisted and kept flying in order that friendly scouts, anywhere in sight, at any time of the day may be able to see and read the message, or copy the signal in numbers for the information of the relieving General, who may possess the key. Simple codes may be arranged in this manner between ships and the shore. It is as easy, however, to telegraph a message, knowing the rules, as to hoist the flags.
To make Night-Signals. --- The flagman is equipped with a signal staff bearing. Fixed at its upper extremity, a lighted torch. This torch is called the flying-light, because the motions are made with it. At the flagman's feet, and in front of him, is a placed a second lighted torch. This is called a foot-light. This is a stationary, and is given a point of reference, or fixed point, in relation to which the motions of the flying-light are made. There are one position and two motions. The first position is when the torch is held vertically above the head, the butt of the staff at the height of the waist, and grasped by both hands, the hands separated form each other about eighteen inches.
The torch being in this position, the first motion is to waved it to the ground on the left-hand side of the torch-bearer, and to instantly return it to the first position. The second motion is to move the torch to the ground on the right-hand side of the torch-bearer, and instantly return it to the first position, The first motion is known for the signal "one," and is indicated by the numeral 1. The second motion is known for the signal "two," and is indicated by the numeral 2. The signal-letters of the alphabet, and the words of messages are then formed as for day signals. To make "front," or "three," the torch is swung to the ground directly in front, and is instantly raised again to the first position. When the torch becomes exhausted, and it is necessary to refill it, to signal message :stop to fill torch,: the flying torch is waved to the left until the staff is horizontal, and is there held. The torch is then extinguished, refilled, lighted again at the foot-light, and returned to the first position. This indicates that the sending of the message is to be continued. To call attention, the torch is swung continually from side to side, passing over the head from right to left, and left to right, until this signal is seen and acknowledged. To acknowledge signals as seen, or messages as received, the torch is waved to the left, two waves at a time, three times. Then once to the front; or, as the signal is recorded, "11,11,5." These signals have the advantage; they are capable of universal application. The mode of making them is very simple and is very easily learned. They are distinct, and easily read. They are very plain. Each signal is, in reality, repeated twice each time it is shown. Thus to wave to the left is read "one;" whether the torch is descending or ascending. It is only necessary to see that the torch is in motion somewhere on the left to read "one." In the same way it is only necessary to note that the torch is waving on the right to read "two." The chances of seeing the signals, are greatly increased. The signals are made very simple apparatus. It is strong, portable, can be carried anywhere (on horse or on foot), is not liable to be damaged by an enemy's firing, or rough handling, and is always available and ready for use. It can be used in almost any situation. The signals can be seen at very considerable distances. Avail can be had of many devices to make them visible. Thus the flags can contrast most strongly with the back ground against which they are visible. The motion of the signal is a valuable auxiliary of its visibility, this motion of the signal object or light producing a long and marked impression upon the retina of the eye. A thing in motion can always be seen and attract attention. when a similar object resting produces no sensation. We recognize this fact instinctively when we wave a handkerchief, or other article, to attract attention. It is never held still for this purpose, and would be ineffective if it were.
The signals made with the ordinary equipment, say a staff twelve feet long, and a flag four feet square, or with the torches at night, are easily legible at a distance of eight miles at almost all times, except in cases of fog and rain. They are read at fifteen miles on days and nights ordinarily clear, and have been legible at twenty-five miles. Greater distances are reported; but it is questionable if, at those distances, there is reliability.
Signals of Two Elements, made with other Apparatus. --- Let a b be an upright staff projecting as through the roof of a house, or though the side on which the ball b can be moved up and down, as by halyards, or by a light iron rod sliding in a groove in an upright. Let c b, be a short fixed rod, bearing the stationary ball c, to indicate the point of rest, or reference. Then the position of the signal ball (plate XXX), is the position of rest and for signals. To call attention, the ball b is moved up and down continually above and below the point of reference, until the signal is acknowledged. The acknowledgment of signals is to make the signal "11. 11. 11. 5," and stop. To make "one," let the ball be slid up above the point of reference (b), and then instantly returned to r. To make "two," the ball is run below the point of reference (to c), and returns to r. Thus to make 121 ("one-two-one"), the ball is run up to b("one"), then down to c (two), then up to b ("one"), and rests to indicate the close of the signal. Thus is one position and two motions, as before described. The first position is with both balls stationary at r, or the point of reference. The first motion is to move the signal ball b to a certain point of reference, and then return to that point. This is the signal "one." The second motion is to run the signal ball b a certain distance below the point of reference (r), and to then return to that point. The ball resting at the point of reference indicates a pause, or stop-signal.
To make 221 ("two-two-one"), the ball is run down twice below the point of reference, and then, without stopping, is run up once above it. It then returns, and rests at the point of reference.
The signal "three," or close of a word, is made by what is called a half motion of the ball; i.e. moving it with a sudden motion above and then below the point of reference. Returning, to rest at the initial point.
To mark a clause, two of these half motions are made. To end a message, three are made.
To make night signals, lanterns may be substituted for two balls. These lanterns may be of the same color. It is better, however, if the fixed lantern be of a different color than the moving light. The signal motions for night signals, are similar to those of the day signals.
The general rules for making the letters of the alphabet,
conventional signals, words and sentences, similarly apply to the motions and the meaning made with these balls as to the motions and the meanings made with the signal flag.
The length of the movement which it is most convenient to give to the signal ball is about that of the arm above the marker ball to make the "ones," and about the same length below to make the "twos."
To work the ball, the signal-man, standing under the deck or roof, if that is desirable, holds grasped in his right hand, and at height of the shoulder, the handle of the signal rod, as at r, (plate XXX). This is the first position.
The signal ball is now at r, the point of reference. To make the first motion, "one," the right arm, the hand still grasping the handle, is quickly extended its full length above the head, and instantly returned to the first position.
To make "two," the hand and arm are extended the full length of the arm below the shoulder, and then returned to the first position.
To make "five," or "three," the pause-signal, a short, quick movement is made above and below the shoulder with the hand holding the rod.
To make "one-one" or 11, the hand and rod-handle is carried twice above the shoulder at arm's-length. To make "two-two," or 22, the hand and rod-handle are carried twice below the shoulder at arm's length. To make "one-two," or 12, the hand and rod-handle are carried once at arm's-length above the shoulder; then, without stopping once at arm's-length below the shoulder. They then rest at the first-position."