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148 



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tion between the signal* given in the table and the letters 

 ornunii'rnls they represent maybe varied almost infinitely; 

 to that if, in time of \viir. (lie key were to fall into tin- 

 hands of the encniv, it miirht be immediately changed. In 

 a modification of tins kind of telegraph, intended for night 

 as well a* for day service, which was submitted to tlir So- 

 of Arta, in 1805, by Mr. Joseph Davis, a seventh 

 shutter or board is added, "which, instead of being . 

 on an horizontal axU, is made to slide up and down in 

 grooves in the centre of the framework ; so that it may 

 i-ithcr range with the Quitters 1 and 2, 3 and 4, or 5 and 0, 

 or, if not required at all, may descend into a space pro- 

 vided for it in the roof of the observatory. By this simple 

 device the power of the machine is quadrupled ; it being 

 rendered capable of making the sixty-three signals shown 

 in the table without the sliding-shutter, and the like num- 

 ber with it in each of its three visible positions, or two 

 hundred and fifty-two changes in the whole. 



About the same time that shutter-telegraphs were being 

 introduced in England, the Chevalier A. N. Edelcrantz, 

 of Stockholm, was devising similar machinery for use in 

 Sweden. In 1796 he published an account of his experi- 

 ments and inventions in the Swedish language, which in 

 1901 was translated into French and published at Paris, 

 and was noticed in Nicholson's ' Journal ' in 1803. A few 

 years later Edelcrantz communicated a model of his tele- 

 graph to the English Society of Arts, in whose Transac- 

 tions ' for 1808 (vol. xxvi., pp. 184-189), it is minutely 

 described. He commenced his experiments in Septem- 

 ber, 1794, with a machine resembling that first employed 

 in France ; but he soon abandoned it, and adopted a shut- 

 ter-telegraph with ten boards or vanes, arranged in three 

 vei-tic-af ranks, of which the centre one has four, and the 

 others three boards each. By this arrangement 1024 

 changes or signals may be clearly shown ; and it would be 

 possible, by observing the order in which the shutters are 

 exhibited, to show 4,037,912 changes. The minute atten- 

 tion required in this case would, however, occasion some 

 uncertainty; and it is not likely that any circumstances 

 could render so many changes at all desirable. Edel- 

 crantz recommends that the vanes or shutters, which are 

 represented as of a square form, should be painted black, 

 and the frames which support them either white or red ; 

 and he says that the intervals between the shutters 

 should be greater than their diameters. The apparatus 

 I'or working the telegraph is ingenious, but too comuli- 



i for description here. It is sufficient to state that, 

 when out of use. the shutters are held open by weights. 

 and that the leverage afforded by the apparatus for closing 

 them is such as to enable one man to hold them all. it 



-sary, against a high wind, which, it is added, could 

 not be aone with the English six-shutter telegraph, not- 

 withstanding the smaller number of vanes, without em- 

 ploying several men. This inconvenience led Mr. Henry 

 Ward, who had observed the difficulty of working the 

 telegraph at Blandford, in Dorsetshire, to contrive an 

 ingenious apparatus which is described in pages 207-8 

 of the same volume of the Transact ion-, ' of the Society ol 

 Arts as that which contains the communication of the Che- 

 valier Edelcrantz. In this apparatus the grooved wheel 

 or pulley which is fixed upon the axis of the shutter, to 

 receive the rope by which it is turned, has the grooved 

 portion of its rim formed in two segments, which are so 

 attached to the periphery of the wheel by steel springs 

 that they fly off' and remain at a little distance from it 

 when there is no strain on the rope ; although, so soon as 

 the rope is pulled, its pressure forces the segments into 

 close contact with the solid vim of the wheel. In the 

 segments are formed two notches, which, when the shutter 

 is in either of its required positions, engage with a lived 

 catch so soon as the strain on the rope is relaxed, and so 

 hold the shutter steady without any aid from the at- 

 tendant. The pulling of the rope, by drawing the seg- 

 ments close to the wheel, releases the catch, and 

 quently enables the attendant to return the shutter to its 

 original position. The ten-shutter telegraph of Edel- 

 crantz had, at the date of his letter to the Society of Arts, 

 been in constant use for twelve years, on both sides ol the 

 Baltic, and in other places in Sweden : - chiefly in facili- 

 tating the communication of posts between Ku>-ia and 

 Finland on one side (of the Baltic), and Sweden and Eng- 

 land on the otlu-r.' He states that one person was suffi- 

 cient for working it and making the observations, espe- 



cially at the terminal stations ; and that six signals were 

 usually given in a minute. 



Lieutenant-Colonel Macdonald, who greatly prefers the 

 numerical to the spelling or lettering system, r< -n m;:; 

 a shutter-telegraph of still greater power, and ci 

 of (greater complexity, than that nf Edclcraiitz. His u-r- 

 telegraph, the advantages of which he lists pleaded 

 at length in two treatises, published in 1808 and 1H17, 

 consists of thirteen shutters, arranged, like thos. 

 crantz, in three vertical sets, w Inch represi clj , 



hundreds, tens, and units. As three boards in c. 

 would only afford seven combinations for each column, 

 he uses four, wjm-h give fifteen combinations, ten of 

 which are used to express the numerals from 1 to 9, and 0, 

 and the remaining five for abbreviations and arbitian 

 nals. The twelve ordinary boards are capable of pro- 

 ducing 4095 distinct combinations, and the thirteenth, or 

 auxiliary hoard, which is mounted over the centre of 1 1k- 

 machine, doubles that number. A flag or vane is added 

 to the hundred side of the apparatus, to distinguish it in 

 whatever direction it may be viewed, and a ball sliding 

 upon the staff which supports it affords the means of again 

 doubling the number; so that, in the whole, l(i,3so dis- 

 tinct signs may be made with this machine. Macdonald 

 recommends that the shutters be made about liv. 

 square ; in which case they may be si-en with a mod 

 telescope, in clear weather, at a distance of ten or eleven 

 miles. 



Although the shutter-telegraph was originally con- 

 sidered an improvement upon that of M. Clumpc, which 

 was so complex as to lead to considerable risk of < 

 unless it were worked by a practised person, experience 

 has established the superiority of telegraphs or sema- 

 phores with moveable arms ; and these hsue been great K sim- 

 plified, so as to avoid the objection raised to the old French 

 telegraph. Among the schemes proposed soon after tin- 

 first practical application of telegraphs, was one which con- 

 sisted in dividing a large circle into twenty-four part 

 the letters of the alphabet, and employing a tra\crsing 

 radius, or index, to point them out ; wires being fixed be- 

 fore the object-glass of the telescope to enable the ill-- 

 tant observer to determine the position of the radius. Tins 

 plan could only be applied to short distances, because re- 

 fraction might render it difficult to distinguish between 

 positions so little \ar\ing from each other. The same 

 radiating principle wits, however, adopted in some ma- 

 chines of more practical character; among which was a 

 telegraph contrived by the Rev. J. Gamble (whose ori- 

 ginal shutter-telegraph lists been before mentioned . con 

 sistiug of five beams or arms pivoted at the top of n post, 

 upon one axis, and capable of producing many dill- 

 combinations without using angles of less than 46 . On a 

 similar principle were constructed the French cosist tele- 

 graphs adopted in 1803, to which the name of .\r//m/ 

 was first applied, and from which it hits been given to 

 other telegraphic machines, the action of winch is de- 

 pendant upon the motion of arms around pivot-, placed at 

 or near their extremities. These French semaphon 

 as they were sometimes called. '. consisted of 



upright posts with two or three mo\ cable arms, turning 

 upon separate pivots, one above the other. Before they 

 were much known in this country. Captain now Major- 

 General . Hasley hsul been led to observe the inferiority of 

 the. common land-telegraph to that used sit sea, which con- 

 sisted of coloured flsigs. and by which three numb' 

 rather three numerals combined to form one number, 

 might he readily expressed. To remedy this defec. 



in 1807 (before ha [,.,,1 M .,. n u, ( . Prencn aemaj 



vi-ed what he termed a |MI|\ grammatic telegraph.' of 

 which he published adecnption ml he twenty-ninth volume 

 of Tilloch's Philosophical Maga/ine.' This machine, 

 which is represented in l'ii; 5, consist ed ol I 



Fig. 5. 



