THE SEMAPHORE.

Southland Times, Volume I, Issue 30, 9 August 1864, Page 3

THE SEMAPHORE.

"WILSON'S COAST AUD HAHBOS TEIEGEAPH SY/STBM. The. system of ocular telegraphy ha9 been now for a considerable period in use, and great and. manifest improvements have been from tinieto time made on tho original design. The first plan we read of was adopted, in 1803, by the French, who erected -''semaphores along their whole line of coast. A retrospective glanco at European affairs at that time will sufficiently explain the motives which induced that nation to establish such sentinel posts around their territory. The semaphore used by them was formed of an upright post, carrying two, or sometimes three beams of wood, each* turning on its own pivot, one above the other. Four years subsequent to this (1807), Captain (afterwards G-cneral) Pasley, of the Royal EngincH.-a, published his " Polygrammatic Tclegftipli," whirl', differed from the French ttiitii by Ritvi% beards turning Oil the same pivot. in brier to db'auri a sufficient niimb'er of different signals, lie suggested the erection of two or three posts at each station to effect this end. The next advance in ocular telegraphy was made by Sir Ilomo Popham, in 1816. He considerably simplified tho construction of hi3 semaphore, and his svstora was adopted that year by the Admiralty, and- has continued in use ever since. It consisted of two anus, moveable on different pivots on the Bame mast, and was capable of giving>forty-eight independent signals. In 1822, we find General Parley still further simplifiying the construction of Sir Home Popham's Telegraph, by placing the two arms on the same axis. The following description will briefly show the mode of its construction, and the manner of using it. It consists of an \iprighfc post, of sufficient height, with two arms moveable on the same pivot on the top of it, and a short arm, called the indicator, is placed horizontally on one side of the post. Each df the arms can exhibit seven different positions, besides the position culled the slop, which points vertically downwards, and i» hid by the post. From these positions (seven to each arm), twenty-eight independent signals can be made. There are thus more than sutlicient for spelling any message, though not enough for indicating the letters of the alphabet at well as the numerical digits. It is to be remarked also that, out of the seven positions, one of them is a perpendicular one, which is a bad •ignal when used by itself, because it appears through the telescope as but a prolongation of the post ; but advantage may be taken of the indicator, if made moveable, to increase the number of combinations. It is worthy of remark, also, that all the systems above described are suitable only for day-signals. We noiv'comc to the more immediate subject of this sketch, i.e., that of Wilson's Coast and Harbor Telegraph System. The designer, Mr. Wilson, has been a resident in Southland for some considerable time past, but was originally in the British navy. We will allow liim to describe his system in hie own langirage, omitting those portions referring to the drawings submitted to us, which, unfortunately for greater clearness, cannot be introduced here. " I have no hesitation (says he) in saying that the conception of the form and every part of this system of ocular telegraphy Originated wholly with myself while serving under the Government^ in tho southern part of New Zealand, in the latter part of 1863 ; and it was there where it was first tested and adopted, being used for the purpose of conveying intelligence to and from the New Kiver Heads and Invercargill, a distance bv the river of some fifteen or sixteen miles. Threo s; r.tions were erected under difficulties and circumstances which at first promised anything but a successful result, arising, in the first instance, out of the want of a sufficiently elevated site on which to erect the intermediate and upper semaphores (no rise whatever presenting itself near the town, which lies very low, and cannot be Been from the Heads) ; and the spot selected for the intermediate one was on S»ndy Point, a loose sand hill lying about midway between the two, at a point where the river has a sharp curve, and from which the upper semaphore, which is placed on a marsh, a short distance from the town, may be seen. Notwithstanding the difficulties thus^ arising, and the generally unpropitious state of the atmosphere on that coast, the semaphores have beeu quite successful, and are found fully equal to the work required of them, being still retained by the Provincial Government of Southland for reporting the daily arrivals and sailings of vessels, the passing of steamers, &c, in the offiing or through Fouveaux Straits, state of the •weather, direction of the wind, &c., &c. " The construction of this semaphore is as follows : _lt consists of five squares, framed and pannelled, and of a size regulated by the distance between the stations, elevation, and other circumstances. When placed together, and painted black or white (according to the general prevailing condition of light and shade at the locality selected), these squares present the semblance of a black or white cross, a form apparently very fovorable for viewing an optical telegraph at a lone distance, and more especially when the sight chosen for exhibiting it is elevated and clear of surrounding objects. Now, the abstraction of any part of such a cruciform figure is readily detected by the eye, and it is on this principle of subtraction, or" subsequent addition thereto, that the form of the various combinations of the squares, denoting the several characters, are produced, and Berve to convey to the mind the symbol representing the figure or letter. " By means of the five squares alone, thirty-two separate or independent signs can be made — a number more than sufficient for representing both the numeral digits and the letters of the alphabet, leaving four combinations to spare to indicate the chief 'distinguishing signals,' i.e., the numeral, vocabulary, rendezvous, and spelling. These last four combinations can also lie made to express (if neeessary) the four series of numbers, viz., units, tens, hundreds, or thousands, when the digits are successively exhibited after either of them, or shown to the right or left of the " squares, either by arms or flags. The squares, or shutters, in the semaphore constructed here, are of the minimum size, 4-ft. 6-in., the maximum should be about 6-ft. The former may be read easily at a distance of seven or eight miles with the telescope, and the latter may be increased in size (if required) without any inconvenience to the working of them. These shutters are so constructed that they may hang and work freely in the frame-work. The two outside upright posts should be six inches square; the two inner ones may be a little less— the cross pieces being in proportion. The height of the lower shutters from the ground should not be leas than seven feet. Tho simple method of opening and .closing the shutters, so as to exhibit the various combinations successively, may be described as follows :— They are suspended by iron bolts (projecting at the side three or four inches), , which are placed a little above the centre of the " shutter, so that the greater weight may be thrown . on to the lower part. This slight preponderance of balance causes them (when the lines attached from the upper part are let go from the rail) to' drop or close of themselves; and from being so nearly equipoised, they may be opened again by a very slight effort on the part of the operator. There are several methods that may be suggested for securing the ends of the line to the rail, but^ the simplest appears to be by cutting slips or' notches in the rail (of sufficient breadth to admit of the rope, being readily moved in and out of them) ; then by making an overhaul knot on the line — to allow for shrinking or expansion — at the exact distance measured between its number shown on the rail and the u^per part of the shutter when "it is open and has a horizontal position. The line i= then entered in the slit, with the knot below it, thus securing the shutter open with only the bare edge presented to view, and which is lost sight of at a short distance. . Lines at the back, of°a similar length} are fastened to keep them in this position. When blowing hard, it is only necessary to set the ,two lineswell taut, and the" wind will have little effect on the which, is otherwise secured with" stays." .--'.— Such is Mr. Wilson's form ..of semaphore. v Hisalphabet may be briefly stated thus:— -Th« five squares, as already, stated, appear inCjthe ,-fprapb.: pfja cross, that isj tared of them are perpendicular, with one on either side of the centre one. The

etters A. B. C. D.: E. are. represented by one square each, commencing at the top and coming round from right to left, tho letter E. being the centre square. Tho letters F. Gr. H. I. are represented by the same squares joined with the. centre one, .and always in the same rotation. K. L. M. IS. are represented by the two .squares, in each corner, and sq on — the whole being most simple and easy of application. This system of optical telegraphing appears to have one decided advantage over other methods, if it could be easily introduced. [Wo refer. to night signals. At present, only day signals are'eommunicated, but 'by a plan for lighting the semaphore by means of the lime or the electric lights; which appears • quite feasible, the usefulness of the system would be considerably increased.