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151 



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impossible in this place. Several depend upon the appli- 

 cation of arms of various forms to a semaphoric telegraph. 

 A two-armed telegraph, of which the two arms are diffe- 

 rently shaped, would be capable of making twice as many 

 signals as a two-armed telegraph with both arms of the 

 same form ; but, for ordinary purposes, such an arrange- 

 ment would have many.disadvantages. A machine of this 

 character, contrived by Mr. Alexander Law, for both land 

 and sea service, is described in the thirty-third volume of 

 the 'Transactions' of the Society of Arts. Another class 

 of telegraphic contrivances depend upon the exhibition of 

 devices or symbols, in a manner somewhat resembling the 

 original contrivance of Dr. Hooke. Of this sort JSIac- 

 donald describes one under the name of the 'symbolic 

 telegraph,' in which symbols resembling those of Hooke, 

 but representing numerals instead of alphabetic characters, 

 are dropped from three boxes or screens into as many 

 open spaces, which have the values of hundreds, tens, and 

 units respectively. An auxiliary shutter, a ball, and a 

 vane or flag, as in his shutter-telegraph, serve to increase 

 the powers of the machine at pleasure. Another contri- 

 vance, which, like the last mentioned, is well adapted for 

 a portable telegraph for use in moderate distances, was 

 invented about the year 1817 by Mr. C'onolly, and de- 

 M'ribed by him in a pamphlet published in that year, in 

 Knglish and French, entitled ' An Essay on universal 

 Telegraphic Communication," and also in the thirty-sixth 

 volume of the 'Transactions' of the Society of Arts. Co- 

 nolly's ' Portable Telegraph' consists simply of three square 

 boards painted with simple devices in black and white, as 

 shown in Fig. 9, the colours on one side being the reverse 

 of those upon the other. The six figures in the upper row 



Fig. 9. 



are thus produced upon three boards, and each of these 

 .-ix figures is capable of producing four different signals, 

 by turning each side of the board downwards in succession, 

 as shown in the four devices at the lower part of the cut. 

 Thus the three boards afford twenty-four distinct signals, 

 which are sufficient for alphabetic communication ; and one 

 only is sufficient for making numerical communications, 

 with the assistance of a smaller paddle-shaped board, the 

 two sides of which, when it is used separately, denote affir- 

 mation or negation. In experiments made at Chatham, 

 boards but eighteen inches square were found sufficient 

 for a distance of two miles, with a telescope with a magni- 

 fying power of twenty-five ; and Mr. Conolly had also, it 

 is stated, exhibited these signals between Gros-nez and 

 Sarque, a distance of seventeen miles, with boards twelve 

 feet square. The day-telegraph of the Rev. James Brem- 

 ner, alluded to in a previous column, consists of a frame- 

 work with two circular openings, in each of which a semi- 

 rircular screen or shutter revolving upon an axis in the 

 centre of the circle, in capable of assuming four different 

 positions. This machine expresses an alphabet of sixteen 

 letters, by dividing the letters into four classes or sets of 

 four each, and making one shutter express the class, and 

 tin- other the number of the letter in that class. Major 



U's Le Hardy communicated to the Society of Arts, in 

 WW, a telegraphic scheme of very different character to 



that have been proposed. His telegraph consists of 



H large frame-work with nine radiating liars, representing 



the numeials from 1 to 9, and four sets of other bars in- 



ting them in such a manner as to form four con- 



i<- poly irons (the whole apparatus having somewhat 

 the ii of a spider's web), which polygons express 



' ( ively units, tens, hundreds, and thousands ; thousands 

 tieing shown by the innermost polygon. Attached to the 

 centre (if the machine by pivots are four slender arms, car- 

 rying as many square boards of sufficient size to be visible 

 ?t a distance ; the respective lengths of these arms being 

 that the board of one may, during the revolution of 

 the arm, traverse the polygon which represents thousand*, 

 that of another the hundreds polygon, &o. The action of 



the apparatus is as follows: If it be desired to express the 

 number 9202, the shortest arm is placed in such a position 

 that its board may rest upon the radius 9, at the point 

 where it is intersected by the thousands or innermost 

 polygon ; the next arm is turned to the radius 2, its board 

 covering the point of intersection between it and the 

 second, or hundreds polygon ; the third arm and board is 

 not called into action at all ; and the fourth is, like the 

 second, turned to the radius 2, the board covering the in- 

 tersection between it and the outermost or units polygon. 

 Thus far therefore the machine can express any number 

 from 1 to 9999 ; but its power is increased by the addition 

 of two other boards at the upper corners, one of which 

 denotes 10,000, and the other 20,000, or, when displayed 

 together, 30,000 ; so that the total range of the telegraph 

 is from 1 to 39,999. 



Several modes of telegraphic communication without 

 machinery, or with nothing which cannot be conveniently 

 carried by hand, have been devised, especially for the 

 purpose of directing military operations, or of conveying 

 speedy intelligence in time of war, where no line of ordi- 

 nary telegraphs can be established. In 1808 such a plan, 

 under the name of an ' anthropo-telegraph,' was laid 

 before the Society of Arts by Mr. Knight Spencer, whose 

 communication was printed in the twenty-seventh volume 

 of their ' Transactions.' Mr. Spencer had observed, in the 

 volunteer service, the inconvenience and loss of time occa- 

 sioned in passing the orders of the commander-in-chief to 

 the officers commanding distant divisions, when a great 

 number of men were manoeuvred together, and this led 

 him to devise the plan alluded to, which he put in practice 

 for the first time in 1805. His apparatus consisted simply 

 of two circular discs of wicker-work, about eighteen inches 

 in diameter, with handles six inches long, painted white, with 

 a black circle or ball in the centre. As these did not weigh 

 more than about a pound each, a man could easily hold 

 them, one in each hand, in any required position. Stand- 

 ing in the position of the first figure in the subjoined 

 cut, Fig. 10, with both discs held down and turned edge- 

 wise to the observer, the telegrapher indicated ' attention' ; 

 in the second position, he expressed a desire to convey in- 

 telligence to the correspondent at a distance; turning 



Kg. 10. 



one-quarter round again, and displaying one disk as shown 

 by the third figure, he expressed the number 1 ; in the 

 next position, 2; in the fifth, 3; 4, 5, and 6 were expressed 

 by positions the reverse of 1, 2, and 3; the right-hand disk 

 being held edgewise, and the other displayed ; 7 was 

 shown by displaying both discs in the lowest position ; 

 8, as shown by the last figure in the cut, by both held out 

 at arm's length ; and 9, by both elevated ; was given by 

 holding both discs above the head, one behind the other, 

 so as to appear but one ; and the signal of ' point ' or 

 ' period,' used at the close of every number, by placing 

 the right hand disc in front of the breast, and the other 

 behind the back, so that, like all the other signals, it might 

 be seen both in front and rear. Another position, formed 

 by displaying the right hand disc in the position 1 and the 

 left hand disc in the position 6, formed a signal of ' error,' 

 to be used in case of any mistake which might require the 

 repetition of a signal. By this simple arrangement any 



