294 CRYPTOGRAPHS AND CIPHERS [CH. XIV 



writing or in some permanent form. Thus to make small 

 muscular movements — such, ex. gr., as talking on the fingers, 

 or breathing long and short in the Morse dot and dash system, 

 or making use of pre-arranged signs by a fan or stick, or 

 flashing signals by light — do not here concern us. 



The mere fact that the message is concealed or secretly 

 conveyed does not make it a cryptograph or cipher. The 

 majority of stories dealing with secret communications are 

 concerned with the artfulness with which the message is con- 

 cealed or conveyed and have nothing to do with cryptographs 

 or ciphers. Many of the ancient instances of secret communi- 

 cation are of this type. Illustrations are to be found in 

 messages conveyed by pigeons, or wrapped round arrows shot 

 over the head of a foe, or written on the paper wrapping of a 

 cigarette, or by the use of ink which becomes visible only when 

 the recipient treats the paper on which it is written by some 

 chemical or physical process. 



Again, a communication in a foreign language or in any 

 recognized notation like shorthand is not an instance of a 

 cipher. A letter in Chinese or Polish or Russian might be 

 often used for conveying a secret message from one part of 

 England to another, but it fails to fulfil our test that if 

 published to all the world it would be concealed, unless sub- 

 mitted to some special investigation. On the other hand, in 

 practice, foreign languages or systems of shorthand which are 

 but little known may serve to conceal a communication better 

 than an easy cipher, for in the last case the key may be 

 found with but little trouble, while in the other cases, though 

 the key may be accessible, it is probable that there are only a 

 few who know where to look for it. 



Cryptographs. I proceed to enumerate some of the better 

 known types of cryptographs. There are at least three distinct 

 types. The types are not exclusive, and any particular crypto- 

 graph may comprise the distinctive feature of two or all the 

 types. 



First Type of Cryptographs {Transposition Type). A crypto- 

 graph of the first type is one in which the successive letters 



