TEL 



150 



1 1 I. 



tre made, when out of use, to lull into grooves or recesses 

 in the post, KO as to become wholly i The nun <- 



menU are effected by means of two winch-handles m-ir 

 the base of the ma*t, within the cabin, one for riu li ami. 

 The winch-handles turn two small vertical bevil-wheels, 

 which communicate motion by means of two horizontal 

 bevil-wheels to long upright shafts or rods, which pass up 

 the inside of the hollow post of the telegraph. At the 

 upper ends of these rods, which are held steady by suitable 

 bearings, are endless screw*, which work into toothed 

 wheels fixed upon the axes of the arms, and thereby com- 

 municate motion to them. In order that the person who 

 works the machine may know pi cci.-eh w hen the arms are 

 brought to the required positions. (-imilar endless 

 are added near the lower eiuls of the vertical rods, to give 

 motion by toothed wheels to indexes, which give a 

 miniature representation of the motion of the arms. Ex- 

 cepting 1he-c indexes and the winch-handles, the whole 

 apparatus is enclosed in the vertical shall of the telegraph, 

 on the outside of which small blocks may be added, to 

 enable a person, with the assistance of a rope from the top 

 of the post, to ascend the machine for the purpose of clean- 

 ing and oiling it. 



About the same time Sir Home Popham proposed a 

 modification of the semaphore for marine purposes, which, 

 ne conceived, would be found very advantageous for the 

 merchant-service, by superseding the necessity fora costly 

 set of signal-flans : the expense and wear and tear of 

 which formed a serious objection to a system of .g. 



graphic communication at sea. excepting in the ships 

 of the East India Company. His proposed sea-telegraph 

 would not, it is stated, cost more than fifty shillings at 

 (list, and it.-- wear and tear would not amount to live shil- 

 lings a year. As the height of an apparatus resembling 

 his land-semaphore would he objectionable for marine 

 purposes, Popham proposed to n.-c two posts twel . 

 two inches high and six inches thick, each having a single 

 arm si\ feet four inches long and ten inches broad, p 

 to the top, but not falling into a slot in the post. as in the 

 last-described machine. In a small slot at the top of earli 

 post is a grooved pulley or sheave fixed upon the same 

 axis as the arm ; and at a convenient height from the 

 bottom of each post another precisely similar pulley is 

 mounted in like way, its axis passing through the post, 

 and carrying a small wheel with four handles at right 

 angles with each other, by which the machine is worked : 

 the motion of the lower pulley being communicated to the 

 upper one, and x consequently to the aim, by an endless 

 rope, which has two or three turns round each of the 

 sheaves, and passes up by the sides of the post. When the 

 telegraph is in use, the posts may be attached to the side 

 of tne vessel by stepping their lower ends into blocks 

 fixed for the purpose, and lashing them to the bulwarks ; 

 or they may be mounted upon trucks, so as to be readily 

 moved from one pail of the ship to another. The descrip- 

 tion of this machine in Sir Home Popham's communica- 

 tion to the Society of Arts mentions but four positions 

 for each arm, and states that when placed in the four 

 positions diagonally to the post, one arm denotes 1, 2, 3, 

 and 4, and the other 5, G, 7, and 8. This arrangement 

 gives twenty-four distinct signals, and avoids the pos- 

 sibility of mistaking the horizontal for an inclined position 

 of either arm, of which there might, owing to the motion 

 of the ship, be some risk. 



May I'li-ley. in a pamphlet published in 1823, 



entitled Di-sciiptioo of the 1'niversal Telegraph for Day 

 and Night Signals,' states that, although bent one time 

 consideied I'opham's arrangement* to be judicious, he 

 now deems the use of two separate pivots in the land- 

 semaphore, and of two posts in that tor marine use. unne- 

 cessary ; and that, conceiving simplicity to be of more 

 consequence than the power of making many chan- 

 distinct signals, he has abandoned the polygrammatic 

 principle, and adopted the simple form shown in the next 

 cut, I' i a. K. which represents wliat he st\ les the ' universal 

 telegraph,' as adapted tor day-service. It consists of an 

 upright post with two aims, both attached to one pivot at 



its uppe 

 even p 



the tl 

 by the 



Knch arm is capable of assuming the 



icated in the cut. besides what i- 



d down m. 

 iiiy-eight distinct signals inn 

 ppparntus, as shown in the suhjoiiud 



table ; these- being more than sufficient for the letters of 





Kg. 8. 



the alphabet, though not numerous enough to allow of a 

 full alphabet and the numeral characters. 



Tu/ilc of the separate or distinct ,s> <;/* pi mi Inj 1'ntley't 

 Universal 



C 



7 



12 



13 



14 



15 



16 

 17 

 2.! 

 24 



25 



2( i 

 27 

 34 



3C 

 37 

 45 

 46 

 47 



50 

 57 

 07 



It had been found, in using Sir Home Poplxim's ship- 

 semaphores, that inconvenience and uncertainty was 

 occasioned by the signals being sometimes seen in i. 

 in which case one number or sign would be confounded 

 with another; and this circumstance having been men- 

 tioned to Pasley by an officer in the navy, he pro 

 against its occurrence with his universal tclegiaph by tin- 

 addition of the auxiliary arm. or indica'- 

 the cut. which, in whatever direction the machine 

 be viewed, distinguishes the side at which the nu- 

 signs commence. It serves also to prevent the p.- 

 marked 4 from being confounded with the stop, which it 

 might be if there were nothing to indicate that the tcle- 

 giaph is nt work, and to enable the eye to n. 



it. The amis and indicator of this telegraph nre 

 iiamed and pannclled. for the sake of lightness, and the 

 former move respectively before and behind tlu 

 indicator only turning up. by means of a rope from I 

 into a cavity in the shall, like the arms of I'opbam's sema- 

 phore. The counterbalance weights of the arms ai- 

 tixed close to the pivot, but extend to some distance from 

 it. in the form of a slender framework of iron, with : 

 at the outer extremity, their light nppeniance rein: 

 them almost invisible at. a distance. The in 

 effected by an endless chain or rope, with a conti:- 

 for keeping it at the necessary degree of ten-ion, as this 

 plan is quicker in action than that of Popham ; but I 1 

 observes that if, ns in a ship-telegraph, a i 

 used instead of n chain, the index attached t. 

 pulley must not be implicitly depended ppon. In : 

 .sequent part of his pamphlet he states that, in \M 

 with n rope, it i- best to have the pulley-groov . 

 angular form, or with notches of the same form, cut into 

 projecting cleats fixed to their circumference, in which 

 case the turns of the rope round the pullcvs may be dis- 

 pensed with. A friend who was well acquainted with the 

 - of the climate of India, recommended to him that 

 no iron should be used in semaphores to be exposed 

 and no wood, excepting tor the post, which maj i 



lie additional parts required to con v < -it the 

 machine into n night-telegraph, for which l.amhoo niny 

 be used. The- pannels of the arms should, in such ,-i 

 be made of thiii sheet-copper, and the other parts of the 

 machine of brass or bronze. Pasley stato that 

 should in general be painted black, and. if ] 



! that they may be seen without any bnckgiotind. 

 It however a background be unavoidable, the i.l.jinph 

 should be of such a colour as to contrast with it. In 

 where the ap; -Aground v 



much nt different periods of the day. it i 



In paint the arms white and black, in ! 

 each occupying half of the width nnd half of the 

 length of the mm. 



The ingenious contrivances which 



for effecting telegraphic communication are so veiy nu- 

 merous, that anything like an enumeration of them is 



