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number might be readily expressed ; and consequently it 

 illicit lx- applied to any numerical dictionary wha' 

 Signals might alto be made at night, by attaching n i'u . - 

 tor-lamps to the disc*, in such a manner that they might 

 hang vertically in every position of the discs, and strapping 

 anotlier lamp, glazed with preen glass, upon the breast of 

 the telegrapher. If intermediate Nations be required, there 

 must also be lamps upon the back of the man and of the 

 dues. The difference of colour between the lamps upon 

 the body of the telegrapher and those attached to the discs 

 U essential to the distinct perception of some of the signals; 

 and the difference between 'attention' and 'point' or 

 period," in nocturnal telegraphing, depends solely upon 

 it. A letter from Admiral Hunter accompanies the descrip- 

 tion ; in which, after expressing a very favourable opinion 

 of the plan, he recommends enlarging the discs to two feet 

 diameter, and painting one side as above described, and 

 the other with a white centre and black rim, so that either 

 might be used, according to the state of the weather. 



In the volume from which the above details are taken, 

 there is also an account of a yet simpler contrivance, in- 

 vented by Lieutenant Sprat t, for telegraphing by means of 

 a white handkerchief, held in various positions to express 

 the numeral characters and a few other convenient signs. 

 The inventor employed this mode of communication some 

 time before the battle of Trafalgar, as a means of carrying 

 on conversation with a distant vessel ; and he had used it 

 successfully to converse between Spithead and the green 

 ramparts at Portsmouth, Sec. \Yilh a common telescope 

 it may be used at a distance of four miles. Macdonald 

 describes some more complicated contrivances of similar 

 character, by the display of small flags, or of two white 

 handkerchiefs and a black hat ; by the latter of which plans 

 between lifty and sixty distinct sitrnals may be made. He 

 also shows how signals may be made to any required extent 

 by men changing their positions from sitting to standing, 

 Sec. Twelve men, arranged in three sets of four men each, 

 may in this way be used instead of his large shutter-tele- 

 graph. 



Some of the earliest methods of telegraphic communica- 

 tion which have been noticed above were essentially 

 adapted for nocturnal use; but in modern times the use 

 of night -signals has not been extensively required, although 

 provision might have been made for their exhibition in con- 

 nection with many day-telegraphs. Thus, for instance, it was 

 proposed to add lamps to the moveable parts of C'happe's 

 telegraph ; and Edelcrantz suggested the application of 

 lamps to his ten-shutter machine. In Davis's seven-shut- 

 ter telegraph, previously described as applied to day-ser- 

 vice, night-signals were to be given by a coloured lamp 

 mounted in the centre of the seventh or sliding shutter, 

 and six white lights attached to the outside of the frame, 

 to produce, by their display or concealment by slides, the 

 same signals as, under ordinary circumstances, are given 

 by the opening and closing of the shutters. These -idc- 

 lamps were to be secured to upright pieces of wood, slid- 

 ing up and down in dovetailed groo\ cs in the outside of 

 the frame-work, so that they might be readily withdrawn 

 when not in use. Provision is made for the adaptation of 

 Pasley's universal telegraph to nocturnal communication 

 by adding a central light at the top of the post, a lamp to 

 the extremity of each arm, and an additional light as an 

 indicator, suspended from a light derrick or crane project- 

 ing horizontally beyond the range of the arms, and on a 

 level with the top of the post. This, the lamps themselves, 

 and 'the additional counterweights required with them, 

 should all be removed during the day. How little neces- 

 sity there is, under ordinary circumstances, for the use of 

 telegraphs by night, at any rate in connection with the 

 navy, may be assumed from the statement of Sir John 

 Barrow, that no attempt was ever made to add lamps to 

 the six-shutter telegraphs formerly used by the Admiralty, 

 notwithstanding the ease with which it might hav 

 done. The semaphores now used by the Admiralty are 

 also constructed without any provision lor the display of 

 night-signals. Macdon.ild's treatise (1817) contains several 

 schemes lor night-telegraphs, both for land and sea : one 

 of which, consisting of three sets of four lights each, with 

 an additional or director light to each set, has the same 

 extensive powers as hi-, favourite large shutter-telegraph. 



Marine telegraphic communication is an object of even 

 greater importance than that winch has been principally 

 treated of in this article, since there are many circum- 



stances which render personal commvmic.il ion between 

 vessels at sea impracticable, and that sometimes in en 

 the greatest emergency. But, although n:: have 



been, of necessity, long used, and flags of various hums 

 and colours have bt-i .uployed for the pur- 



pose of making them, it was not till within a compam- 

 recent period that they were reduced to anything 

 like an efficient telegraphic system. Sir John B; 

 states (Kuril. Hrtt., ait. -Navy'i that -The idea of num- 

 bering the flags, and of assigning a certain number of cor- 

 responding sentences to certain combinations 

 numbers, was reduced to something approaching a regular 

 system in the fleet of Lord Howe ;' and that in th- 

 1798 a new signal-book was issued by the Admiralty, the 

 references to which were made by a numerical anange- 

 ment of flags. This book contained about four hundred 

 sentences, expressive of the most usual operations of the 

 fleet : but it was so imperfect that, if any order had to be 

 transmitted which was not to be found in the dictionary, it 

 became necessary to make the signal for 'a boat from 

 each ship;' an order which could not alsvavs be complied 

 with. This inconvenience was remedied by the plan, sug- 

 gested by Sir Home Popham, of making the flag-signals 

 represent the letters of the alphabet, a> well as words and 

 sentences, in connection with numbers. This individual 

 also printed, at Calcutta, a new code of naval signals, which 

 was subsequently reprinted in England, greatly extended, 

 and adopted for use in the navy. Among the nuin< 

 improvements introduced by him is a new method of cut- 

 ting the signal flags, so that, as he explained to the Society 

 of Arts in 1816, 'the selvages of the buntin are brought 

 on the outer edges of the flags, and the gorings in tin- 

 centre ; by which means the outer < ceptible of 

 the least air of wind, and when the flag blow- out. the 

 gorings assist in keeping it out ; whereas the old flags had 

 a hem on the outside, which rendered them difficult to I c 

 moved without a fresh breeze, especially in damp and 

 rainy weather, as the hem then became very h 

 Besides,' he adds, ' it is impossible, from the nature of the 

 buntin, to sew a straight seam, for the instant it is cut it 

 will become in some degree curved.' (Truiistictimii, vl. 

 xxxiv.. ]>. 174.) The only objection urged by Barrow to 

 the code of naval signals now in use is one which i- 

 applicable, more or less, to all that have been subsequently 

 proposed, namely, the great number of flags, Jcc.. required 

 for making numerical signals to the extent laid (town ; 

 which, in the code in question, amount to nine flag-. Use 

 cornettes, five triangles, and five pendants. With such a 

 number, he states, it is next to impossible, in calm weather, 

 to make out the figure, and colour of the flags ; and equally 

 so when, though expanded by the wind, the situation of 

 the observer causes them to present only an edge towards 

 the eye. He conceives that Poaham's sea-telegraph, be- 

 fore described, is capable of entirely removing this diffi- 

 culty : and that possibly Pasley's universal telegraph might 

 be applied in like way with ad'vantagc. 



The principle of the numerical system as applied to 

 flag-telegraphs in the nasy i- briefly explained by Mae- 

 donald. .Nine different, variegated flag- air employed to 

 express the numerals 1 to !l, another for 0, and another, 

 called a sulmtittili; to repeat am Hag under which il is 

 hoisted, in case of the same numeral occurring twice m 

 the number to be expressed. A pendant is also used in 

 some cases as a substitute for the uppermost figure ; and 

 thus, by the use of eleven different flags and a pendant, 

 any number from 1 to !)S)!( may be expressed without di 

 playing more than three flags, or two flags and a pendant, 

 at once. In a telegraphic -y-lcm desised by Mr. ( 'onolh , 

 and fully explained in the Transactions ' of the Society 

 of Arts ior 1817 (vol. xxxv., pp. 205-208 ,ft plied 



to express numbers in a different manner to tin- above. 

 The basis of the system is an alphabetical list of the most 

 necessary English words, arranged in a tabular form like 

 the figures in the common multiplication table : the 

 column- and horizontal lines being numbered. Then 

 ninety-nine of each: and consequently the numb' 

 squares or divisions is !)sol. The number of words is how- 

 ever great e, in some cases. here no ambiguity 

 is likely to be I by it. the radical word and 

 several of Jta modifications arc placed in a I ire or 

 disi.-ion of the table. The sign:i jiiare 

 T the mum-nils and (I. a substitute, and a pre- 

 parative signal), the same number of triangular flags, of 



