,J»4 ''0» tin Art of cmveyitig Secret and Smlp Intel/igf»ee. 



thcfe data. The cipher of each word is an ifolatecL fa£t, which teads to nothing farther. 

 Suppofe the knowledge of any panicuhir vocabulary AkmiM fall into han'd« for which it 

 was not intended, a flight. change in the numeration, without; any aflual change of the 

 figures, would entirely prevent difcovery :—- For inftance, if die Lord Lieutenant wiflied 

 to fend orders to the Commander in Chief ; if he made ufe of the numbers written in the 

 vocabulary in one day, he might, after previous communication, employ a different nu- 

 meration by ordering that i (for inflance) fliouul be added to every figure. If clafs ii. 

 number 3664, ftood in the vocabulary for gunpowder by the addition which I have pro- 

 pofed, the number would ftand clafs iii. number 4775, which might mean a crocodile, or 

 'I ippoo Saib, or any thing foreign to the real word. Gy fimilar provifions any number of 

 feparate correfpondents might carry on a mutual intercourfe, without interfering with one 

 another. 



In the courfe of twelve months I tried a great number of experiments^ and carried on 

 a great number of converfations with the tellograph ; of all thefe a regular journal has 

 been kept, containing what was unfuccefsful, as well as what fucceeded. If fuch journals 

 were kept in the profecution of philofophical puifuits, they would pay for the trouble of 

 keeping them by the accuracy of the experience which they enfure. 



I fhall not at prefent enter into any detail of my No6turnal Tellograph. Its velocity 

 far exceeds what can be done by day, as in clear weather flations at fifty miles diftancc 

 may be plainly diftinguiflied. 



When this paper was firfl prefented to the Academy, I had determined to try an expe- 

 riment acrcfs the Channel from Donaghadee to Port- Patrick. I was ambitious of being 

 the firft perfon who (hould conneft the iflands more clofely, by facilitating their mutual 

 Intercourfe. Public bufinefs prevented me from going to the fea-fide at the time I 

 had intended, and from carrying on a feries of converfations by day and night be- 

 tween the two kingdoms ; but Mr. Lovell Edgeworth, my fon, had the fatisfa£lion of 

 fending four mefTages acrofs the Channel at four o'clock P. M. on the 24th of Augufl 

 1795, and of receiving immediate anfwers before a vaft concourfe of people. The ma- 

 chines by which this communication was made, were thirty feet high, and fifteen feet at 

 the bafe. A child of four years old could turn them. Mifly weather prevented them 

 from being feen; but when the weather cleared up, a pointer of twelve feet high could 

 have been plainly diflinguifhed acrofs the Channel. 



Though I have beftowed much attention and labour upon this fubjeft, I do not pretend 

 to fay that the means of tellographic communication, which I have invented, arc the beft 

 that can be devifed. Imitations without end may be attempted; pointers of various fhapes 

 and materials may be employed ; real improvements will alfo probably be made; and, per- 

 haps, new principles may be adopted. 1 he varieties of art are infinite, and none but 

 perfons of narrow underftanding, who feel a want of refources in their own invention, 

 are jealous of competition and difpofed to monopolize diftoveries. The thing itfelf mufl 

 fooner or later prevail, for utility convinces and governs mankind ; and however inatten- 

 tion or timidity may for a time impede its progrefs, 1 will venture to predift, that it 

 will at fome future period be generally pra£lifed not only in thefe iflands, but that it will 

 jn time become a means of communication between the moft dillant parts of the world, 

 wherever arts and fciences have civilized maakind. 



TABLE. 



