90 Mr. Chenevix mi a new Method 



own labour more than the public money. A cipher, which 

 should fulfil the second condition of Lord- Bacon, might be a 

 means of economy in all countries where communication by the 

 post office is safe and unrestricted ; and at all events might give 

 additional security to the expensive mode of couriers against the 

 accidents to which they and their despatches are exposed. 



One of the oldest and most celebrated modes of secret writing 

 is the Spartan seytale ; but those by means of which the best 

 hope of practically accomplishing the intention of Lord Bacon 

 may be entertained, may be reduced under two heads : — 1st, 

 resolving the sentence to be written into its letters, and then distri- 

 buting those letters in another order, according to a known rule, 

 which rule forms the key of the cipher : — and 2nd, the substitu- 

 tion of fictitious symbols, in lieu of the true letter of a sentence ; 

 which symbols have a value determined by previous convention. 

 In the former, the true letters of the sentence are revealed to the 

 eye ; but their import is concealed by their dispersion. In the 

 latter, the order of the real letters determines the order of the 

 symbols ; but their meaning is disguised under the conventional 

 value attributed to those symbols. 



As to the first of Lord Bacon's rules, the latter mode of cipher- 

 ing may be so contrived as to offer some advantages. When a 

 single symbol is substituted for a single letter, the additional 

 time and labour which secret writing requires more than common 

 writing, consist in the interruption inevitable whenever it be- 

 comes necessary to consult the key ; and this must happen 

 almost at every letter. However, it is possible so to construct 

 a diagram, as considerably to reduce the fastidiousness of this 

 operation ; whereas the division of a phrase demands that it 

 should be first written out, and the letters counted and dispersed; 

 and then copied again in their artificial order. But a single 

 operation is sufficient for the method by substitution ; and, if 

 the phrase is long, the unmeaning words may be written in let- 

 ters, the rest in symbols. 



With regard to his second rule, that the cipher should not be 

 easily deciphered, substitution has infinite supericfrity. Be the 

 letters of a sentence dispersed as they may, study can detect 



