METHOD OF SECRET WRITING. 247 



Take a rule of pafteboard, wood," ivory, or copper, about New method by 

 one inch broad and feven inches long, divide its edge into 30 po f lt j on# 

 equal parts, and between the divifions write the firft thirty 

 natural numbers, from 1 to 30 inclufive, in any arbitrary order. 

 The following is the manner of ufing this rule. 



Operation for writing. Firft make a minute or outline of the The pj"°cefs, 

 fecret you with to fend, then place the rule or fteganographic 

 fcale on the paper intended for the fecret, and mark the two 

 ends of the rule by two fmall lines of ink, the reafon of which 

 will be feen below. 



This being done, tranfcribe the firft thirty letters of the mi- 

 nute, writing the firft letter oppofite to the figure 1, on the 

 rule, the fecond oppofite to the figure 2, the third oppofite to 

 the figure 3, and fo on to the end. 



Bring down the rule and tranfcribe in a fimilar manner, 

 oppofite to the figures, the next thirty letters of the fecret, 

 that is to fay, from the thirty-firft to the fixtieth inclufive. 



Continue thus transcribing in new lines, each confifting of 

 thirty letters, until the whole fecret is written. 



The punctuation muft be carefully inferted to the right of 

 that letter which is on its left in the minute, and a mark like 

 this -f- muft be placed above the laft letter of each word, to 

 diftinguifh it from that which follows, and thus render the 

 reading eafy to the correfpondent. 



Operation of the correfpondent. The correfpondent who re- To decypher. 

 ceives the fecret with the letters thus mifplaced, will be able 

 to tranfcribe it, and replace the letters in their proper order, 

 by inverting the preceding operation. 



For this purpofe, he muft be provided with a rule fimilar to 

 that made ufe of for deranging the letters of the fecret. He 

 will place it on the firft line, fo that the letters correfpond 

 with the figures on the rule. This will be eafily accompliiried 

 by means of the two lines of ink which mark the ends of the 

 rule. 



It will then be eafy for him to tranfcribe the letters of the 

 fecret in their proper order, beginning with that oppofite to 



in its capability of being employed by all the world, without dimi- 

 nifhing its feciecy for each individual j it will be feen that, in this 

 plan, it is the fecret of the feries agreed on, and not that of the 

 method, which renders the conefpondence fafe. 



figure 



