They are now read from left to right and from the first line down, like ordinary reading matter. They are then grouped into fives for telegraphic transmission, and an X added at the end to make an even five-group there. Thus the message, as transmitted, reads:
SADUL RRYAL TOHOF TRLNO IRNEI
MZNPI EEIPE PGOMC APYTU LAYHM
EBOOM NRNOT TESTX
When this message is received, it can, of course, be quickly deciphered by printing it out on a chess board and placing over it a sheet perforated according to the prearranged pattern.
This survey of codes and ciphers does not more than scratch the surface of the subject, nor more than suggest the almost infinite variations that are possible—in ciphers especially. It simply gives a groundwork for an understanding of the German secret messages now to be described.
EXTRACTS FROM A GERMAN CODE EXPERT’S BLOTTER
Showing the use of capital letters in the actual work of enciphering a message, and the combined use of cipher and code
Among the most interesting of these secret messages is the series of wireless telegrams by means of which the German money was paid to Bolo Pasha for the purchase of the Paris Journal—one of the principal episodes in the treasonable intrigue for which Bolo was recently executed by a French firing squad. These messages were in English, and meant exactly what they said, except for the proper names and the figures, which were code. To decode them, it was necessary only to make the following substitutions: