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CHAPTER XIV. 



CRYPTOGRAPHS AND CIPHERS. 



The art of constructing cryptographs or ciphers — intelligible 

 to those who know the key and unintelligible to others — has 

 been studied for centuries. Their usefulness on certain occasions, 

 especially in time of war, is obvious, while their right interpre- 

 tation may be a matter of great importance to those from whom 

 the key is concealed. But the romance connected with the 

 subject, the not uncommon desire to discover a secret, and the 

 implied challenge to the ingenuity of all from whom it is hidden, 

 have attracted to the subject the attention of many to whom 

 its utility is a matter of indifference. 



Among the best known of the older authorities on the 

 subject are J. Tritheim of Spanheim, G. Porta of Naples, 

 G. Cardan, J. F. Niceron, J. Wilkins, and E. A. Poe. More 

 modern writers are J. E. Bailey in the Encyclopaedia Britan- 

 nica, E. B. von Wostrowitz of Vienna, 1881, F. Delastelle of 

 Paris, 1902, and J. L. Kliiber of Tubingen, 1809. My know- 

 ledge, however, is largely the result of casual reading, and I 

 prefer to discuss the subject as it has presented itself to me, 

 with no attempt to make it historically complete. 



Most writers use the words cryptograph and cipher as 

 synonymous. I employ them, however, with different mean- 

 ings, which I proceed to define. 



A cryptograph may be defined as a manner of writing in 

 which the letters or symbols employed are used in their normal 

 sense, bub are so arranged that the communication is intelligible 



