Description of an improved Telegraph. 345 



Reference to the Engraving of Major Charles Le IIakdy's 

 Telegraph. See Plate VI J I. Figs. \ 9 2, 3, and 4. 



This machine is intended to express numbers, which mav 

 be seen at a distance, and to which words may be referred 

 at pleasure. 



Fig. 1 represents a front view of the machine — lit is com- 

 posed of nine bars or radii, answering to the nine figures of 

 arithmetic, as numhertd in the plate. The four polygonal 

 or concentric bars, A. B.C. 1). which intersect the radii, are 

 for the decimals ; thus A stands for units, B for tens, C for 

 hundreds, D for thousands. Over each of these concentric 

 bars or circles, an index,, as that marked H, fig. 2, tra- 

 verses, which marks the number of thousands, of hundreds, 

 of tens, and of units, as far as ten thousand ; for instance, 

 if it is required to make the number 920-2, turn the hand II 

 in the circle D of thousands to the radius 9, then the hand 

 II in the circle C of hundreds to the radius 2, then, as there 

 are no tens, turn the hand to the radius 2, upon the circle 

 A of units ; but as ten thousands are not sufficient to ex- 

 press the number of words in the English language, two 

 square boards are added in the corners, of which that mark- 

 ed E is equal to 10,000, that marked F to 20,000, and both 

 being shown together, are equal to 30,000, which, with 

 the numbers made on the circles, bring it op to 40,000, 

 which number is more by many thousands than all the words 

 in tiie Englisti language. 



Fig. 2 is a view of the mechanism which works the sig- 

 nals round : this is done by means of a rack whee) at ]", 

 upon which is firmly fixed the hand with its signal board H; 

 this wheel is made to revolve by means of a rack L, which 

 being raised or lowered, makes it go backwards or forwards; 

 this rack is set in motion by the pinion K, to which is "fixed 

 a winch, as M, fig. 3. To prevent the necessity of inspect- 

 ing the signals, the wheel I, to which is fixed an index, as 

 at N, fig. 4, is added, which revolving in the same time as 

 the signal board H, marks the number of the decimal, so 

 that it may be worked correctly from within doors. O, 

 pg. 4, is a bolt to stop the hands at any given point, by 



nicans 



