War signals in code

Press, 28 August 1984, Page 10

War signals in code

Codes have played a part in history since the time of earliest civilisation. The ancient Hebrew prophets, Isaih and Jeremiah, used a form of code to conceal the real meaning of their prophecies. There are some examples of this in the Bible. Julins Caesar used an alphabet cipher to conceal his real messages to his generals fighting in various parts of the Roman empire. The science of writing concealed messages is called cryptography. This was developed in the middle ages when it became a popular form of sending political or military messages.

In those days there were no telephones, and messages had to be carried by hand. Codes and ciphers were used to prevent an important message falling into the wrong hands. The flags which are used for signals between ships are a type of code which has been used for hundreds of years. The semaphore code was developed in the early 19th century. In this code different letters of the alphabet are represented by the holding of one’s arms in certain positions. By holding flags it is possible to send semaphore messages quite a long distance. One of the best known

codes is that invented by Samuel Morse. Each letter in the Morse code is represented by a different group of short signals (dots) and long signals (dashes). These groups can be sent as flashes of light, wavings of a flag, or buzzes of sound. Blind people are able to read with the help of the Braille code. In this the letters of the alphabet are represented by varying arrangements of six raised dots.

African tribes signal to each other by beating out messages on drums, a system known as the “bush telegraph.” Some large drums will carry sound up' to 30 km.