METHOD OF SECRET WRITING. 249 



with four feries, and may ferye for four correfpondents : if it 

 be of ivory, the feries may be changed at pleafure, by writing 

 the figures with a pencil : the fcale may even be compofed of 

 thirty fmall detached moveable pieces of brafs flipped upon a 

 flat iron rod, and fecured with a nut at one of its ends. 



3. It may be eafily conceived, that the principles of permu- Other permata- 

 tation may be varied to infinity, for inftance, by changing only 



the order of the fyllables, the words, or the lines. The above 

 method on which 1 have fixed, appears to be at once eafy, 

 certain, and concife, and to require the fimpleft apparatus. 



4. If it be defired to conceal even the appearance of a fe- 

 cret, the method above defcribed may be employed to write 

 with one of the fympathetic inks, at the end of an oftenfibJe 

 fubje6c. 



5. Another ??iethod. Having divided the paper into 100 or Another method 

 200 fquares, write in each a letter, a fyllable, or a word of the by the fcale > 

 fecret, and alfo one of the numbers of the concerted feries : 



feparate and mix the fquares ; the correfpondent will only be 

 required to replace them in their order by means of the figures 

 of the feries. 



For the greater fecurity, the edges of the fquares ihould be 

 pared to deftroy the connection of the adjoining fides. 



6. Method of intercalations. Draw on pafteboard, fome pa- father by 

 rallel divifions about half an inch afunder, pierce them w ; t h interca}ation - 

 holes, either equal or unequal, of an arbitrary fize, and at any 

 diftance from each other : lay the pafteboard on the paper, 



and write the fecret by inferting fucceflively from left to right, 

 a letter, fyllable, or word in each vacancy : remove the pafte- 

 board and fill up the intervals with infignificant letters; or it 

 will be better, if time permit, that the letters fhould form with 

 thofe of the fecret, a reafonable meaning, not liable to be fuf- 

 pecled, 



The correfpondent will eafily read the fecret through holes 

 in a fimilar pafteboard. 



The infertion of unmeaning letters may be avoided by ufing 

 three or four pafteboards of equal fize, but fo pierced, that 

 when they are laid on each other, all the holes will be clofed. 

 By writing through each of thefe in fucceflion, all the lines 

 will be filled. The correfpondent muft be provided with fimi- 

 lar pafteboards, and will read the fecret through them by ap- 

 plying them fucceflively to the writing. 



This 



