Flag Signal Instructor Wheel 1917
This Flag Signal Instructor Wheel was manufactured and sold by the Flag Signal Instructor Co., Maryland.
It was a teaching tool for the Army and Navy for learning the International Morse Code and Semaphore or Two Flag Code.
It has a 1917 patent date for Great Britain and Canada and June 12, 1917 for the United States and is in excellent shape and
the wheel turns easily to reveal
the Morse Code or Flag Signal.
The orginal sale price was 25 cents.
Semaphore is a communication method in which a person signals with two hand flags, moving his arms through various positions to represent letters, numerals,
and special signs. Flashing light and Semaphore can be used interchangeably for many purposes, but semaphore is more rapid for
short-distance transmission in clear daylight and may be used to send messages to several addressees at once if they are in
suitable positions. Because of its speed, semaphore is better adapted to the sending of long messages than are other visual methods.
When radio silence is imposed, semaphore is the best substitute for handling administrative traffic. It is more secure than a
light or radio because there is less chance for interception by unauthorized persons.
Both the ancient Greeks and the Romans are known to have signaled over short distances with torches and flags.
The telescope, invented in about 1600, greatly increased the range of such systems.
In 1794, Claude Chappe, a French engineer, devised a semaphore that could carry a message 230 km (144 m) from Lille to Paris in two minutes.
He constructed a series of towers about 8 to 16 km (5 to 10 mi) apart and within sight of each other. On each tower was mounted a pivoted beam
with arms at the end. A telescope was located at each tower so that an operator could relay the beam-arm signals.
The electric telegraph supplanted Chappe's semaphore for long-distance signaling in about 1850; however, Hutton Gregory, a telegraph engineer on the British railroads,
modified Chappe's system by employing moving metal arms or rows of lights, mounted on towers, to signal trains. The railway semaphore is still in use.
Semaphores also remain in use for maritime communications.
The U.S. Navy uses a system in which an operator grasps half-red and half-yellow flags; the arms are extended at various angles
to indicate letters of the alphabet.
link to the complete alphabet online