In a war, good intel is crucial. The opposing armies always use codes in messages so that their plans are not known. Breaking codes is not an easy task, nor is it a quick task. During World War I, the cryptanalysis section of the British Admiralty was called Room 40, also known as 40 O.B. (Old Building) (latterly NID25). The unit was formed in October 1914. It began when Rear-Admiral Henry Oliver, the Director of Naval Intelligence, gave intercepts from the German radio station at Nauen, near Berlin, to Director of Naval Education Alfred Ewing, who constructed ciphers as a hobby.

Ewing began recruiting civilians such as William Montgomery, who was a translator of theological works from German, and Nigel de Grey, who was a publisher. During the war, the war Room 40 decrypted around 15,000 intercepted German communications from wireless and telegraph traffic. The section’s most notable work was when they intercepted and decoded the Zimmermann Telegram, a secret diplomatic communication issued from the German Foreign Office in January 1917 that proposed a military alliance between Germany and Mexico. This was the most significant intelligence triumph for Britain during World War I, because it played a significant role in drawing the then-neutral United States into the conflict.

Room 40 operations began simply with the acquisition of a captured German naval codebook, the Signalbuch der Kaiserlichen Marine (SKM), and maps (containing coded squares) that Britain’s Russian allies had passed on to the Admiralty. Before long it was playing a vital part in the intelligence industry. It all started when the Russians seized this material from the German cruiser SMS Magdeburg after it ran aground off the Estonian coast on August 26, 1914. The Russians recovered three of the four copies that the warship had carried. They retained two and passed the other to the British. In October 1914 the British also obtained the Imperial German Navy’s Handelsschiffsverkehrsbuch (HVB), a codebook used by German naval warships, merchantmen, naval zeppelins and U-Boats. The Royal Australian Navy seized a copy from the Australian-German steamer Hobart on October 11th. Then, on November 30th, a British trawler recovered a safe from the sunken German destroyer S-119, in which was found the Verkehrsbuch (VB), the code used by the Germans to communicate with naval attachés, embassies and warships overseas. It was an amazing find. In March 1915 a British detachment impounded the luggage of Wilhelm Wassmuss, a German agent in Persia and shipped it, unopened, to London, where the Director of Naval Intelligence, Admiral Sir William Reginald Hall discovered that it contained the German Diplomatic Code Book, Code No. 13040.

The section retained “Room 40” as its informal name even though it expanded during the war and moved into other offices. Alfred Ewing directed Room 40 until May 1917, when direct control passed to Captain (later Admiral) Reginald ‘Blinker’ Hall, assisted by William Milbourne James. Although Room 40 successfully decrypted Imperial German communications throughout World War I, its function was compromised by the Admiralty’s insistence that all decoded information would only be analyzed by Naval specialists. This meant while Room 40 operators could decrypt the encoded messages they were not permitted to understand or interpret the information themselves. Whatever they couldn’t do, they accomplished a very great deal.

Communication over the years has not always been easy. Before mail service, the people sent messages via horse and riders, called post riders. I’m sure that messages were only sent in this way when the message was really important, because it would be silly to pay someone to send a simple letter, or notes like our text messages of today. Just imagine that cost if the messages went back and forth as much as texts do. Nevertheless, post riders were the only way to get a message out in 1791. Inventions happen at a time when they are least expected, and just because it was 1791, doesn’t mean that the next year couldn’t bring something amazing. In this case, that is exactly what happened.

After seeing the problems there were with communications, Claude Chappe of France invented a system of communication that he called the Semaphore Machine. In reality it was an early form of the telegraph system we all know about. The machine was used until the nineteenth century when the telegraph was invented. The Semaphore system was much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. The system worked by conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the shutters. It is read when the shutter is in a fixed position. The lines were a precursor to the electrical telegraph. It was also considered more private, which seems odd to me. How could a message relayed from the top of a tower be private? Of course, not everyone knew how to read the messages, but it would seem like there would be a few people who learned the codes and so could read the messages. Still, I suppose that the people who translated the messages were sworn to secrecy.

The system did have its drawbacks. The distance that this optical telegraph could bridge was limited by geography and weather. It could not be seen in rain or snow, and could not be seen over a hill. That limited its practical use. The solution was to use relay stations to reach longer distances. Of course, the system couldn’t cross expanses of water, unless a convenient island could be used for a relay station. While the system had its problems, it did serve a useful purpose in its time. In some forms, it is still used today. One modern version of the semaphore system is a flag semaphore, or a flag relay system. Another is the heliograph, which is an optical telegraph using mirror-directed sunlight reflections. I think anyone who has watched a movie about ships might recognize that one. It was how they signaled from one ship to another. Maybe the Semaphore Telegraph system wasn’t so antiquated after all.

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