GILBERT SIGNAL ENGINEERING
Complete and thorough
instructions in all forms of Signaling
with Signal Corps U. S.
Navy Prepared under the Direction of
A. C. GILBERT
Yale University, 1909
THE A. C. GILBERT COMPANY
San Francisco Toronto
BY A. C. GILBERT
NEW HAVEN, CONN.
HISTORY OF SIGNALING 7
GENERAL SERVICE CODE AND ITS USES 14
Wigwag system - The flag, limitations and backgrounds - The
torch and lantern wigwag - Wigwagging by searchlight.
III. GENERAL INFORMATION
ADVICE TO SIGNALISTS 27
message - Duties of a signal unit - Interruption of messages -
Intervals - Code time.
IV. SEMAPHORE SYSTEM
semaphore machine - Two-arm semaphore by hand flags.
V. SOUND AND FLASH LIGHT
signals by bugle - Signaling by pocket whistle - Flashing or
light system - The blinker - The acetylene lantern - Searchlight
signaling - The heliograph - The Ardois system - The Very
AND TELEPHONY 59
- The American Morse Code Receiving telegraphy - Radio-telegraphy
Telephony - The telephone for signal purposes.
VII. THE SIGNAL TOWER
for erecting a signal tower - Secret codes and ciphers - The
disc - How to make a cipher outfit.
VIII. MARITIME SIGNALING
and correct way of using - Flags of the International Code and how
- Method of signaling when no other ships are in sight - Distant
signals - International flag waving system.
IX. U. S. NAVY FLAG
How navy signals are executed - Calls - U. S.
naval flag etiquette - Time for flying colors - Personal flags -
MISCELLANEOUS SIGNALS 95
life saving signals - Signals for a pilot - International distress
signals, for day - International distress signals, for night.
XI. HOW TO MAKE SIGNAL
to make a field buzzer - How to make a heliograph - How to make a
semaphore and blinker.
do big things, just as men do who are experts in a certain kind
endeavor, I believe is the greatest wish of every boy. I know
was a boy it was very interesting to me to find out all I could
electricity, chemistry and other practical subjects because they
my attention. There was all kinds of fun in this for me.
I got working on my experiments I had the greatest amount of
Let me tell you, too, I was a happy boy when I had completed my
and could show it to others.
I remember how I used
army men at signal practice. It was mighty fascinating to see
the camp with their apparatus and to observe the methods they
send messages. It looked hard, but when I thought it over it
Signaling will prove just as
interesting to you as
it did to me, and because I think it means a great amount of fun
you, I have had this book prepared by a man who was an expert in
signals and who did very fine work in the Navy as a member of
Signal Corps. Every detail is explained with the greatest care.
facts are authentic and you can depend on this book to give you
thorough knowledge of signaling. You can learn about signals
very beginning when firebrands were used in a primitive fashion
years ago to the present time when messages are flashed and sent
most modern inventions.
7 GILBERT SIGNAL ENGINEERING
teams of the U. S. Army and Navy on the roof
Grand Central Palace, New York City, during a recent signal
Webster's Dictionary we find that the meaning for signal is a
in looking up sign find its definition to be signaling hence
certainly very closely related. At any rate a signalman is one
signs into action and that is what we are going to do, By a
perseverance you will master
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lesson step by step and in a very short time, with the ease of a
signalman, be able to flash a message through space for a
twenty miles or more.
The early American Indians
picturegraph messages on the bark of trees, their canvas wigwams
other conspicuous places. The totem pole of the Northwest and
Indians is a good example of symbol writing. In later years the
advanced tribes devised crude codes by which they sent messages
means of smoke.
Many hundreds of years ago the
in Europe put into practice the habit of carving picturegraph
on rocks. Like the American Indians, they later found methods of
sending their messages through Space with the aid of
code and lighted torches.
Boy Scouts in mountain
of N. Y. State signaling from a platform errected in a tree.
Courtesy of Boy Scouts of America.
seems that the earliest forms of optical telegraphy, as visual
signaling is sometimes called, involved the use of firebrands or
torches. Ofcourse these could only be used at night and , and
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signals at a Scout Camp.
Courtesy of Boy Scouts of
Boy Scouts of a
Denver, Colo., Troop practicing semaphore.
Scouts of America
10 GILBERT BOY
tory gives us no
records of any day signals until the earlier forms of semaphore
hundreds of years later.
200 B. C. a method of signaling was employed by the Greeks, in
torches were used. A system of measuring the flashes or
exposures so as
to make a simple code was invented.
torches for signaling, and during the early Greek and Roman Wars
probably the first step was taken in Signal Corps organization.
warrior signalmen were known as "fire shakers," and to obtain
vantage they built in many places throughout Europe signal
some of which are still standing to this day.
in the Old Testament of lighting signal fires for the purpose of
conveying intelligence. It seems that the method of using signal
and torches was very popular among the early signalmen. The fact
remains that even as late as the Civil War in America torches
still in use by the Signal Corps of the Blue and Gray Armies and
rivaled today only by the more modern devices in which lanterns
electric lights are used.
In the year 1623 the
Marquis of Worcester (England), invented a plan of letters for
signaling by day and night.
(France 1663) recommended the holding up of large letters of the
alphabet to be viewed by telescope.
Hook of England was the first to really develop the modern idea
visual signaling. He used various shaped objects, suspended on a
to indicate letters of the alphabet.
Chappe, a young
French engineer, in 1790 invented a system of semaphore, and
Frenchmen followed him with the more advanced forms of
During the reign of Queen
Duke of York (later James II) introduced a system of methodized
from which later sprang the first British Naval Code.
11 GILBERT SIGNAL
Signalmen of the U. S.
signal bridge of the U. S. "Wyoming"
12 GILBERT BOY
1816 Sir Home Popham of the British Navy gave the world a new
semaphore telegraph, which was adopted by the British Admiralty.
Penn of America is also given credit for being among the first
the first) to get together a code and system for communication
reviewing the history of signaling it might be of interest to
the first telescope was invented about the year 1600. This
invention increased the range of the naked eye to a very great
and made signaling an important method of communication.
needs for signaling, we can see, were first wanted by armies so
bring about rapid exchange of thoughts. It proved faster and
reliable than messengers, who were always subject to delays or
to capture. Still, today, its paramount use is found in the
navies of the world, where the Signal Corps is without a doubt
In November, 1863, during the
Civil War in
America, when General Grant took command of the Union Army
Chattanooga he established his Signal Corps on a big
was able to keep in touch with his forces during many of the
battles, one of which was the famous "Battle Above the Clouds"
on Lookout Mountain. Today this mountain, from which his Signal
operated, is called Signal Mountain and will stand as an
monument to the Signal Corps. If it is ever your good luck to
this beautiful spot in Tennessee you will then realize to what
accurate signals were and can be exchanged.
war the Allied armies used many ingenious methods of signaling,
including the improved blinker systems, sound systems and radio.
the newest schemes is that of sending a message from the ground
aeroplanes by means of
13 GILBERT SIGNAL ENGINEERING
"Panels." This is done
code and panels of colored cloth laid on the ground.
importance of Signal Corps work can be realized better when it
that the Signal Corps of the U. S. Army alone, during the time
part in the war, used 126,000 miles of wire for intelligence
communications by telephone and telegraph lines. (Liaison work.)
scientific knowledge of our neighboring planets will undoubtedly
accomplished by means of high powered signal apparatus. The
an exchange of messages with the inhabitants (if any) of these
is receiving serious thought by many scientists. Several years
plan was advanced to do this by means of the heliograph method.
scheme was to use great mirrors with a huge shutter arrangement
to send the messages by means of great flashes. Who can tell but
you may be able to invent the apparatus to send a message that
would, of course, take years to develop, but some one will
find a way to complete this wonder system in signaling.
14 GILBERT BOY
GENERAL SERVICE CODE AND
code of signals is a collection of symbols agreed upon. The
International Morse or Continental Code is the most widely used
modern codes due to its easy adaptability to so many forms of
The International Morse Code was first
transmitting messages by ocean cables and later adopted by the
and navies of the United States and Great Britian. By the
recognition of the Army and Navy, the Boy Scouts and other
organizations it has come to be known as the "General Service
From this point on in the book it will be called by that term.
General Service Code is a code of dots and dashes comprising the
twenty-six letters of the alphabet and the numerals, with
The following signal
are based on this code:
1. Sound system.
3. The Ardois system.
Flashing or occulting light system.
5. Very's night system.
The Wigwag system.
8. Buzzer and Field
U. S. Army, commercial telegraph lines and short cables at the
time use the American Morse which has slightly different
15 GILBERT SIGNAL
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using the General Service Code with some of the systerm just
it is necessary at times to make some minor changes in the
of sending numerals and conventional signals, but the principle
code always remains the same. The changes will be explained from
to time as you become familiar with the systems.
readily see the importance of knowing this code before any
be made in signaling; so now turn to Chart 1 where you will
the General Service Code alphabel and numerals written.
study the alphabet. A good plan that will help you to
will be to write over and over again the characters on paper,
which you can get another boy to test your memory by
call out at random letters of the alphabet to you. You can reply
dots and dashes. Another way is to construct short sentences and
rewrite them under the dot and dash characters. For
numerals of the code are much easier to learn than the alphabet.
will note that they are written by using a combination of five
dashes for each number. Remember numbers are always represented
dots, dashes, or a combination of both. Number one is made with
followed by four dashes, .
- - - ; number two by adding
17 GILBERT SIGNAL
18 GILBERT BOY
19 GILBERT SIGNAL
another dot and dropping
dash, . . - -
-. This same plan is followed until you reach
number six, when you start with one dash followed by four dots - . . . For number
seven write two dashes and drop one of the dots, - - . . . ,
and so on down the line to zero which is expressed by five
dashes - - - - -
2 gives the punctuation marks of the code, secondary meanings of
several letters of code alphabet, conventional signals and
abbreviations, most of which were taken originally from the
Morse Code but are adaptable to all methods of signaling and are
by every practical signalist.
abbreviations, no matter what the system, always remember they
as a complete word.
that you know the General Service Code, you are ready to make
this knowledge by practicing short messages with the Wigwag
the Army, for practicing the wigwag, a stick of light wood about
inches long is used, and is called the wand. The wand is held
between the thumb and forefinger and waved rapidly to right or
indicate letters of the code. A wand can be made easily from the
end of a bamboo pole or any
Chart 3 you will see illustrated a boy holding the single stick
position or ready. He is standing erect and facing squarely the
receiving station which is represented on the chart. The flag is
vertically in line with center of head. This position with three
motions constitutes the Wigwag System.
chart at the
left is shown the first motion, which represents the dot. To
motion the flag is waved from position to right of sender and
position. This mo-
20 GILBERT BOY
Members of a U. S.
Corps Company wigwagging from a signal tower erected on roof
building at Vera Cruz, Mexico
Courtesy of U.
S. Marine Corps
tion is always made in a
at right angles to the line connecting the two stations as shown
center of your chart.
The second motion shown on
right of chart gives you the dash and is made exactly as above
left of sender.
third motion shown at bottom of the chart is made by a wave of
from position directly in front of sender to your feet, and
returning to position or ready. This third motion represents
or interval. One front motion is given at end of each word, two
of a sentence and three upon completion of a message. In making
letter of the alphabet say the letter Q four strokes are made ;
LEFT LEFT RIGHT LEFT. It is not necessary to pause at position
from extreme left to right or vice versa. However, a slight
should be allowed
GILBERT SIGNAL ENGINEERING
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at the completion of
letter. Then continue to finish your word and to give the front
great deal of practice is necessary to become a rapid sender by
single stick flag. Care should be taken not to foul the flag on
staff, as the full fly of your flag should always be seen by
receiving station. This is sometimes hard to do, especially on a
day, but experience will teach you how it is best to avoid a
U. S. Army uses two standard outfits for wigwagging. These are
the Signal Corps as kits. The two-foot kit contains a
hickory staff, jointed with brass screw ferrules, and when
together makes a strong pole 69 inches long. The flag is made
pole by means of three ties of tape. These are looped through
eyes on pole.
Two flags, the size of each being 2
are provided, one of bright red material with a white center 8
square and the other white with red center. The flags and pole
packed in a canvas kit about 2 feet in length.
other outfit used is the "four-foot kit." In this outfit the
Boy Scouts sending a
Courtesy of Boy Scouts of
23 GILBERT SIGNAL
is heavier and when jointed is 12 feet in length. The two flags
feet 9 inches square with 12-inch centers; they are of alternating
colors, red and white, as in the smaller outfit.
FLAG, LIMITATIONS AND
size of the wigwag flag to be used depends entirely on the
want to transmit a message, and whether or not the receiving
equipped with glasses. Under ordinary conditions a flag of 18
2 feet can be read a distance of one mile without glasses and
with glasses. This is the extreme limit for a flag of that size.
all single stick flags are made up of a combination of red and
colors, as these colors usually give greatest contrast. Red and
is also a good combination.
Always select the
color of your
flag so as to give greatest possible contrast against the
The white flag should never be used where your background is a
snow-covered hill or light sky; but if sky is heavily clouded a
flag will prove best. The red flag should be used against a
background, of course. As some backare very de-
Boy Scouts of Ansonia,
sending a long distance wigwag message at sundown
of Boy Scouts of America
24 GILBERT BOY
ceiving at times, it
a little study on your part to determine the proper flag to use
TORCH AND LANTERN WIGWAG
At night the signal flag
no use; the substitute is either the torch or lantern.
you are out in the woods and want to send a message at night to
adjoining camp and have no torch or lantern at hand it is great
use firebrands. Selected sticks of dry wood can be placed in the
fire and lallowed to burn a minute or two. The signalist can
a message to his comrades. It will surprise you to learn the
you can send messages by this method. Care should be taken to
of range of your camp fire, as its reflection would hinder the
receiving party. Signaling at night is always subject to
A U. S. Marine
Haiti, West Indies.
Courtesy of U. S.
25 GILBERT SIGNAL
U. S. Army Signal Corps
adverse conditions than by day. Therefore it is advisable to
messages much slower at night. Where the distance is great, an
additional light should be placed in line with center of your
about 2 feet from the ground to act as an indicator or point of
reference in the motion.
About the most practical
wigwagging at night is to use two lanterns, one for the
and the other for transmitting. Care should be given at night to
front motion, so as to make it distinct. This motion can be
somewhat by moving the lantern vertically from your head to your
indicator light. For long distances you can fasten a lantern to
Science Notebook" Copyright 2008-2013 - Norman Young