THE SOUTH FORELAND LIGHTS.

Waikato Times, Volume III, Issue 147, 17 April 1873, Page 2

THE SOUTH FORELAND LIGHTS.

Ov the Ist of January, l»7i, Sir Frederick Arrow, the Deputy Master of the Trinity Board in London, uccomf panied" by Captains Drew and > r c»bitt, Elder Brethren; armed in Dover lrom London, lor the purpose of inaugurate" ing the electric light at the South Foreland, which is m successful operation in the lighthouses at Dungeness, Souter Point (at the nioutii of the Tj ne) , Cape Grumes (on the French coast between Calais and Boulogne), and \anou* other localities in France. Built upon the edge ot the ehus, between Dover and Deal, the appearance of the two towers nud other buildings is exceedingly picturesque ; these arc the South Foreland Lights, and, as the beacons to the npp'oaches to the North Sea and the mouth of the Thames,, with the additional fact of the Goodwin Sands l^ing about (hive miles to the eastward, are oi an importance second to none in the kingdom. Since their establishment, m 1631, the\ hive been the means ot say n^ countless lhes, m\d> an incalculable amount ot property Cher 200 a cars ago the warning lights consisted snnph of huge coal iires. In 1790 oil was Mibstiluted, and with the exception of u few weeks in. IKSS, when Hie electric lights was experimented with, oil lamp* continued in use until the end ot 187 1. During tliat jp.ir the Trnnh Board erected at a cost of £3,000 to £6,000, a building betwixt tbe two towers, which are -it 9 yards apart. This consists of an engme-iooui and boiling-houses, a coal store, workshop, and residences lor engineers and keepers. The engine-room eoutnina a quantity of elaborate machinery,, all in duplicate, so that in case of am accident to one inline, or apparatus, the other could be used. The machinery ior producing the electricity required for the light towers consists of four frame*,. composed of numbers of large magnets. The moment one of the hon/ontal condensing engines is *et in motion, the electric fluid is generated, and passing lrom the frame* along the wires tliat rise above them, is flashed to the tow ers through an underground cable. The electric machines, four in number, make 400 revolutions every minute, and at th.it rate cfl'eut an alternation in the ! direction of the currents of 6,400 times in every 60 seconds. As a rule only two of the machines are m use, but in case of a dense fog the whole iour would be put m motion. The two condensing engines work up to 20-horse power, and can, jbe u»cd cither at high pressure or condensing ; one of them lis sunieient to drive the lour magnetic machines. Professor Holmes is the imenlor of these imvchines, while the telegraphic communication which exists between the enginehouse and the beacons, and by means- of which messages are sent from the keepers to the engineers, or vice versd, is on> the Wheat stone principle. The lantern of each tower is I composed of glass in the highest state of polish, and tho extren.e delicacy in the construction of the apparatus used to illuminate it is difficult to be described. The lanterns, howp\er, contain optical apparatus of the dimensions of a* third order for fixed lights, and specially designed and manufactured for the purposes of electric illuminations, i From the high lighthouse, which is 372 feet above high water, 21(3 degrees of the arc surface is illuminated, and at the lower tower, 273 ieet above high water, 199 degrees. At sunset the attendant places the apparatus im the centre of the lantern, and hawng guarded his eyes with a pair of green spectacles-, he communicates by wire iwtli the engine-room. The moment the machinery there is set in motion a brilliant light bursts out between the two fine points of carbon, which, nearly touching each other, are fixed in the apparatus lengthways, and. are kept in. position by a delicate clockwork apparatus. This light, reflected by the polished glass, furnishes the illumination, and such< is tbe completeness of the apparatus that the landward arc of the light, instead of being wasted, is carefully gathered up, and, by reflecting prisms arranged on each side, is equally distributed over the portion of the sea face illuminated by the main apparatus, liteially overlapping the chief light, and adding veiy considerably to its power. Should any accident occur to the light, such as the carbon points being biokun, the centi c apparatus is immediately lemoved, a duplicate substituted tor it, and in a minute the light is again in focus. In the event of the electricapparatus becoming tempoiarily useless, the dioptric oil lamp is raised to the centre, and in about three minutes is burning brightly in place of the electric spark. The works were designed by Mesaia Douglas, the engineers to the Trinity Boaid ; the electric apparatus was constructed by Professor Holmes and Messrs Blackett Brothers, Ijondon - r and the optical apparatus by Messrs Chance Brother of the well-known glassworks near Birmir>gham. Mr J. J. (Jhance of that firm, designated the optical, portions of the apparatus, and has in them displayed his thorough knowledge of optical science as applied, to lighthouses. The steam-engines, boilers, pumps, Sec, wereconstructed by Messrs Hunter and English, of London. Tho completion of tho works at the Foreland forms a triangle of electric lights, described by those of Dungeness, Cape (Irisnez, and the South Foreland itself. The atafT employed consists of James Core, who is chief engineer, and seven assistants, all of whom reside either in the cottages attached to the engine-house, or at the light-towers. Everything has been found to work satisfactorily. At Duugenness, how e\er, several vessels hove been wrecked, owing tothe extreme brilliancy of the electric light rendering it impossible for the crews to distinguish objects betw ecu themselves, and the- shore when m close proximity to the lighthouse. For general purpoocs the light fulfils its mission admirably. The fog-horns with which it is intended to supply the South Foreland will not be- completed until theautumn of the present year; in fact, there are no signs yet of their being commenced. They will be sounded by compressed air, and will be heard at a distance of seven miles inland, or about double that distance at sea. Professor Holmes is the patentee of the fog-horns,, as also-ef tho electric hglit.