Telegraphs of thi French an^ of Robert 'lionh. * 4f* 



^n EJay on the^rt of conveying 'Secret and Sivift Intelligence, By RlCHAKJi -LorELt. 

 ' '''EvGEWORTiiyEfq.F.R.S.andM.R.I.J.*. 



M, 



.ODELS of the French T'elegraph have been fo often exhibited, and the machine 

 iifelf is To well known, that it is not neceiTary to defcribe it minutely in this place. Ic is 

 fufEcient to fay, that it Gonfifts of a tall pole, with three moveable arms, winch may be 

 fceri at a confiderable diilance through telefcopes ; chefe arms may be fet in as many dif- 

 ferent pofitions as are requifite, to exprefs all the letters of the alphabet : — By a fuccefhve 

 combination of letters ihewn in this manner, words and fentences are formed, and intel- 

 ligence communicated. No doubt can be made of the utility of this machine, as it has 

 been applied to the mod important purpofes. It is obvioufly liable to miftakes, from the 

 number of changes requifite for each word, and from the velocity with which it muft be 

 moved to convey intelligence with any tolerable expedition. 



The name, however, which is -well chofen, has become fo familiar, that I fliall with a 

 flight alteration adopt it for the apparatus which I am going to defcribe. Telegraph is a 

 proper name for a machine, wliich dcfcribes at a diflance. Telelograph, or contrafledly 

 Tellogrdph, is a proper name for a machine that defcribes -words at a diilance. 



Dr. Hooke, to whom every mechanic philofopher muft recur, has written an eflay upon 

 the fubjedt of conveying fwift intelligence, in which he propofes to ufe large wooden 

 letters in fucceffion. The fiege of Vienna turned his attention to the bufinefs. This 

 method is more cumbrous than the French Telegraph, but far lefs liable to error. 



I tried it before I had feen Hooke's work in the year 1 767, in London ; and I could 

 diftinftly read letters illuminated with lamps in Hampflead church-yard, from the houfe 

 of Mr. Elers in Great Ruflel Street, Bloomfbury, to whom I refer for the date and cir- 

 cumftance. — ^To him and to Mr. E. Dclaval, F.R.S. to Mr. Perrot of Harehatch, and to 

 Mr. Woulfe the chemift, I refer for the precedency which I claim in this invention. In 

 that year I invented the idea oF my prefent tellograph, propofing to make ufe of windmill 

 fails, inftead of the hands or pointers which I now employ. Mr. Perrot was fo good as 

 to accompany me more than once to a hill near his houfe, to obferve with a telefcope a 

 windmill ait Nettlebed } which places are, I think, fixteen miles afunder. My intention at 

 that time was, to contrive not only a fwift but an unfufpedled mode of intelligence : By 



■• Tranfaftions of the R. Irifli Academy, vi. 125. The firft part of this pap«r confifts of near thirty pages 

 of very iaierefting hiftorical detail, refpeftin^ the art of conveying inrclliiicncc by founds and llgnaU. Jt was 

 praftifed by Thefeus, in the Argonautic expedition ; by Agarnemnon, at the fuge of Troy ; arnl by Mardonius, 

 in the time of Xerxes. It is frequently mentioned in Thucydides; it was ufed by Tamerlane; by the Moors 

 in Spain ; and by the Welch in Britain ; by the Irifli ; and by the Chinefc, on their famous wall of fifteen 

 hundred miles, by which they fcparatcd themfelvcs from Tarcary. I have omitted litis part on account of its 

 length. • 



T t 2 means 



