German plot messages, therefore, are usually written out first in plain German, then coded, and the code then put into cipher. Such messages are called _enciphered code_. For an enemy to get them to make sense, he has first to decipher them, and then decode them. Any expert can decipher them--in time. Decoding them is a very different matter. Before taking up some of the German code and cipher messages that have been translated, with dramatic results, it will be well to discuss codes and ciphers in general. A _code_ is an arrangement by which two people agree, when exchanging messages, always to substitute certain words or symbols for the real words of the message. Thus, they might agree on these substitutions: a = the French ship = market sailed from New York = price sailed from Boston = quotation to-day = is for Marseilles = any even number for Bordeaux = any number with a fraction With such a code, a German spy in New York could cable a seemingly harmless message to a friend in Holland, such as: “The market price is 110.” That would mean, of course: “A French ship sailed from New York to-day for Marseilles.” Whereas a very slight change in wording: “The market quotation is 110¾.” would mean: “A French ship sailed from Boston to-day for Bordeaux.” [Illustration: CODE MESSAGE TRANSMITTING MONEY TO SIR ROGER CASEMENT In English it reads: “Embassy. 307-16, New York, April 10, 1916. Mr. John Devoy has paid in $500 here with the request that they be transmitted telegraphically to Sir Roger Casement. You are respectfully requested to proceed accordingly and to charge the amount to the Military Information Bureau. Receipt enclosed.”] Messages of that sort could be exchanged daily between a broker in Wall Street and a broker in Amsterdam, and, by the addition of a few more words, could be infinitely varied and would look like perfectly legitimate commercial correspondence. In fact, most international business before the war (the Government now requires that all messages appear in plain English) was carried on by coded cables which turned long messages into short groups of words that of themselves made gibberish. Several code books for business use were on the market, containing hundreds of pages of these arbitrary substitutions, which were useful, not for secrecy but for economy. A dozen words could be made to say what normally would require five hundred words.