320 0» fie Art ef ceiweying Secret and S-wlft Tnielllgtrtee, 



means of common windmills this might have been cffefted, before an accountof the 

 French Telegraph was made public *. 



My machinery confifts of four triangular pointers or hands, each of which points like ' 

 the hands of a clock to different fituations, in the circles which they defcribe. 



It Is eafy to diftinguilh whether a hand moving vertically, points perpendicularly down- 

 wards or upwards, horizontally to the right or left, or to any of the four intermediate 

 fituations. 



The eye can eafily perceive the eight different pofitions in which one of the pointers is 

 reprefented, plate xiii. fig. i. by turning the eye to the circle A. 



A fimilar circle may be imagined round each of the pointers, by which the numbers 

 which they are intended to exprefs, may be difcovered with much facility. 



Of thefe eight pofitions, feven only are emj)]oyed to denote figures ; the upright pofition 

 of the hand or pointer being referved to reprefent O or Zero. The figures thus denoted,, 

 refer to a vocabulary in which all the words are numbered. Of the four pointers, plate 1. 

 that which appears to the left hand of the obferver, reprefents thoufands, the others hun- 

 dreds, tens and units in fucceffion, as in common numeration. 



t In the annexed plate the four large pointers (land at 2774, which in the common ar^ 

 rangement of my vocabulary, denotes the Royal Irifh Academy. For permanent ftations, 

 which may be feen clearly with tolerable glaffes at twenty miles dillance, ftone or wooden 

 pillars fixteen or twenty feet high mud be folidly erefted : on the top of thefe a move- 

 able circle, or platform, turns horizontally upon a centre: on this platform an axis moves- 

 vertically, and carries the arm or pointer along with it. Eight handles turn the pointers, 



• Since this paper was written I received a letter from Mr. Perrot, which lias been feen by the Prefidcnr, 

 containing the following paffage. 



" I pcrfeftly recoUeft having feveral converfationt with you in t^(>7, on the fubjtft of a fpeedy and fecrer 

 " conveyance of intelligence t I recolleft our going up the hills, to fee how far and how diftinftly the arms 

 «' (and the pofition of them) of Ntttlebed windmill werc^ to be difcovered with cafe. As to tlie experiments 

 'y from Highgate to London, by means of lamps, 1 was not prefent at the time ; but J remember your mentinn- 

 " ing the circumftance to me, I believe in the fame year. All thefe particulars were brought very ftrongly to 

 '•my memory, when the French a few years ago conveyed intelligence by fignals; and I then thought and 

 " declared, that the merit of the invention undoubtedly belonged to you. ---I am very glad that I have it in 

 " my power to lend you this confirmation, bccaufe I imagine there is no other perfon now living who can wit- 

 " nefs your obfervations in Berkihire."' 



f I infcrr, Plate xiii. fig. »• a line defcrjbed by telegraphs as an example. — It is the firft lineof thefallowins- 

 verfes, written on the profpeft of correfponding between England and Ireland by the Telegraph : 

 Hark from Bafaltic rocks a^d giant walls. 

 To Britain's (bores the glad Hibcrnia calls; 

 Her voice no longer waits, retarding tides. 

 The meeting coafls na more the fea divides. 

 Quick, at the voice of forttinc, or of fame, 

 Kindles from fhore to fbore the patriot rtamc ; 

 Hov'rin" in air, each kindred genius I'miles, 

 And binds with clofer bands the filler iije.4. 

 The numbtrs are, 4645, 2331, 573> >"3> *44' '4") ^il^- 



which 



