On the Art of eonvtying Secret end S^vi/t Inielligetice. ^VL 



wliicfi are fixed in their different pofitions by a catch or alidad. By means of the platform, 

 the piimter may be turned to any part of the compafs; and as one fide of it is painted 

 black and the other white, either fide may be employed, as th^ colour of the clouds, or the 

 Ctuation of the place, may require. 



Befides thefe permanent machines, of which dimenfions and a defcription are fubjoined 

 in plate xiii. I make ufc of portable machines, (which may be detached like tentacula from 

 the main body in hazy weather,) confiding of pointers ten or twelve feet high, and of a 

 light triangular (land, which can be eafily fattened with tent pegs to the ground : thefe may 

 be lodged i;i any houfe near the place where they are ufed, or in times of danger may 

 be carried bsck to the permanent ftations every night. 



In managing a correfpondence by thefe machines, it is neceflary to have certain fignals- 

 eflabliflied : nor are thefe fignals merely arbitrary ; it is abfolutely neceflary that they 

 fhould be made by the two external or by the two internal pointers, elfe they could not 

 be repeated by the intermediate flations without confufion ; becaufe, in the middle flations, 

 that pointer which reprefents thoufands when conveying a mefiage eaftward for inftartce,. 

 mult, when anfwer is returned in an oppofite dlredion, reprefent units ; the fame change 

 will take place between the pointers that denote hundreds and tens. 



Certain hours of the day muft be appointed for ordinary communication. Suppofe 

 ten o'clock in the morning, and five in the afternoon in fummer. Every communication 

 begins from the capical. If no intelligence is required to be conveyed from thence, the 

 word BEGIN is fent to the county ftation, which may then proceed or difmifs the 

 meeting. 



When any communication is to be commenced, the pointers that denote thoufands and 

 units are whirled round, till the fame is done at the correfponding ftation. When this 

 fignal has been anfwered, the perfon who gave it proceeds to fend his intelligence. As 

 foon as he begins, the pointer of hundreds at the oppofite ftation is turned to two, and 

 kept in that pofition till the word is made out from the vocabulary} it is then turned up 

 to O or Zero. The perfon who is fpeaking, when he perceives by this fignal that he is 

 underftood, turns all the machines to nought, wliich is always to be done at the conclu- 

 fion of every word. 



When all his machines are in this pofition, his correfpondent again turns his pointer be- 

 longing to the place of hundreds to two, where it is to remain till he receives another word,, 

 and fo on till all that is meant to be faid is finifhed. To denote that his communication^ 

 is finifhed * — thousands and units are to be vibrated backwards and forwards with 

 the point downwards like a pendulum, till the fame is done at the oppofite ftation. 



If any interruption takes place on either fide, from a cloud, a fliower, or any accident,, 

 it is pointed out by vibrating thousands and units with their points upwards; which 

 fignal muft be repeated from the oppofite ftation. Whoever has made the fignal of inter- 

 ruption, muft make a fignal of recommencement, when he is ready to proceed, by vibrating: 

 HUNDREDS and TENS, wlth their points upwards; when this is anfwered (but not before,) ' 



* I ufe the words Thoufands and Units here, and in the reft of this defcription, for the ppinters or machines 

 tliat ftand in tlve nuiperical place of thoufands asd units, 



the.; 



