AT NIGHT ON A LIGHTHOUSE.

Otago Witness, Issue 2811, 29 January 1908, Page 13

AT NIGHT ON A LIGHTHOUSE.

TENDING THE LIGHTS - :

By Will Lawsox,

The tall tower which rears its head 300 ft above sea-level shows pale in the twilight, 'lnere is still a last glow of the" sunset in the west, very faint and rapidly fadjng, and the lamp has just been lighted by the keeper, who will te-r.d it until 8 ''clock. It is now 1, so that this first vigil of the night is a short one. ~ Brilliant beams of intense white-ness" flash from" the revolving lantern — a double flash every 30 seconds, with five-6econd interval between the separate flashes, — nov^ illuminating the bare • hillside, , -now throwing 'dazzling, sweeping shafts 30 miles out seaward and many more leagues into space. It is like a gigauttc sensitive finger feeling and prying into the infinite. A soft breeze is blowing off the sea — the level, far-stretching, shimmering eea, -which seems to breathe in regular respirations, at each breath a fresh burst of foam appearing on the rocks far below. Yet no sound of the slow breakers reaches the watcher in the high tower. The stars gleam more brightly as the afterglow pales. It is a night of beauty beyond words, of peace beyond prayer, and of loneliness too keen to" find expression in longing, for the immensity of the world comes home to the heart of man f.ill he feels himself an intruder, an invader in these domains of Nature — he and his winking lanterns. Away southward, a mast-head light twinkles and below it a tiny pin-point of .red marks a steamer's port light. Overhead the flash, flash^of th-& lantern sends across the distance its legions of light — now here, now there, till the dark queen N:ght, bewildered md wounded by the stabbing scimitars, gives pause and bids her warriors leave me great bright star in peace. The lamp wherein are created these blades of light is at the top of the tower. It i 6 a first-order dioptric light, yet the burner is hardly larger than that o£ an ordinary house lamp.. The power and intensity of its beams are obtained by the use of lenses and prisms of glass set in. a circular framework which revolves round the burner. Weights operating massive clockwork propel the lantern in ite orbit. The huge ball of lenses and prisms is beautiful to look at as the three-sided prisms reflect all the colours of the rainbow. It is, 'however, painful to the eyes to meet the full power of the light, and the keepers ■wear glasses of a dark tint when their duties demand that they face the full effulgence — a Tadiance which, when emitted by a fixed light in a steady beam, attracts bewildered sea birds over miles of ocean to dash their soft bodies against the lantern" like moths to a candle.

Apart from the problems of architecture, the history of lighthouse design and improvement has marched hand in hand with that of optics. The Tays of light are directed laterally so as to shine across the waters. Any light thrown upwards or downwards would be wasted, as would any thrown upon a non-reflecting material. The earlier light reflectors were made of burnished metal or mirrors ; lamps so fitted are called catoptric lights. Then glpes prisms — three-sided bars of pure glass — were used in conjunction with lenses, constituting what is called the dioptric light, such .as are in use on the New Zealand coasts. There is only one light in u.e Dominion which is not in this class, that on Dog Island being catadioptric — that is, having a combination of metal and glass refractors. Perfection in the dioptric light was attained by a French scientist, by name August Fresnel, -who in 1822 devised a totally-reflecting prism. He also achieved distinction as the designer of an annular lens and a cylindric Tefractor, and his efforts brought the dioptric form of light into general use ; Taut, like many other successful men, his triumph stood on the failures of earlier industrious students, of whom Buffon. in 1748, was probably the pioneer. The modern lamp in a first-class lighthouse is not tlie work of a year nor of a score of -rears, but of centuri-es of experiment and r-esearch. It is a triumph of persistence.

More power is required for a fixed light thin for a revolving one of the same intensity of bsam, owing to the fact that the fixed lamp must radiate light from every side, <vhile a revolving one has all its power- concentrated in one beam •which sweeps the compass. On the New Zealand coast kerosene is burned, a firstclass light requiring from 1000 to 1500 gallons of oil in the year. In one or two lighthouses the incandescent burner has been installed, with great increase of lio;ht on a less consumption of oil, and other lirzhts are to be similarly fitted. The original lampwick was a flat one. Then in 1782 Argemt introduced wicks and burners of a hollow, cylindric form, which ■vrere perfected by the indefatigable August Fresnel. The. oil for the light is raised from the beach on a steep tramway operated by a hand winch. There is also a zig-zag path leading up from the keepers' cottages on the beach. At every few yards patches of white paint are smeared on the •rock to mark the way in the dark. Up this track the head keeper k now climbing, to relieve the second keeper and to take the watch from 8 to midnight. From sunset till sunrise the light must be tended, and the watches are: From sunset to 8, from 8 to 12, from 12 to 4, and from 4 till dawn. In the summer there are only two watches, .as the sun lingers late and returns early, givins the keepers respite- if the light is not also a signalling station. When this is the case some one must always be on lookout duty, and at such stations there are always three keepers. At all isolated stations the keepers are also three y in number. At mainland lights two men are stationed. The necessity for three men at isolated places was demonstrated many years ago at a lonely rock light on the British coast, where two keepers, the only in">*bitanta of the tony island, vrere

stationed. One of them died a storm which lasted many days. On the mainland the surviving keeper's distress signals were seen, and attempts were made to effect a landing but without success. ..When the s_ea_ abated the boat's crew, on "reaching the light, found to -their horror one man dead and the other one mad. Yet the light had been tended faithfully by the sorely tried survivor. r J£he of the night watches is " intenser- "The . .cottages of the k&epers are usually situated at some distance trom the tower, communication being maintained in some cases. by telephone, m others, by a code of signals made on a bo'&n's w-histle. A keeper questioned as to what the "lighthouse men do to while j away' the time replied, "We read. ' And j this is borne out by the appeiranco of I the little room immediately below the I lantern, in 'which the keepers eit in the i intervals of their visits to the light. It is furnished with a table and chairs ; i a few charts, clock, and other instruments j are on the walls; and there are sheltes of books, books, books, and illustrated papers, though not enough to satisfy the omnivorous readers on the lonely outposts of the world. At the out-stations the mail is delivered regularly — four times a year. At some mainland stations quite a frequent communication is maintained with the world ; tv ldle at others the telephone br.ngs them in touch with life. These are j signalling stations. At such places there I is a mast and jardarm, or a- yardarm projects from the tower. On this storm. ' signals to shipping are .exhibited and signals from passing vessels replied to. Th* 1 one great care of the man on watch is to see that the lamp burns and revolves. The heavy weights must be i rewound several t mes during the nip,ht, ! necessitating a constant wakefulness, and a log is kept similar to that of a ship.

At midnight the watch changes again. Tnera is no ceremony, no corporal of the guard with the night relief, no clang of bell and lookout's cheery challenge. The new •watchman visits the lantern, sees that all i& in order, and returns to the bcok ho was reading when he went off ■duty four hours ago. So the watch is kept, the light maintained to send its beams of stinging whiteness flash — flashing through the night. At 4 o"clock, when the watch is again changed, there is a greying of the eastern sky, -which betokens a snort visil till dawn. Standing on the gallery which encircles the tower just blow the level of the lantern, on© feels a keenness in the air and there is a slaty blueness on the ocean's breast. Overhead the lorg shafts oil light sweep in pairs, sending their rad;ance bravely eastward, jealous of a greater light than theirs. Seen from the gallery the lantern presents a peculiar effect. There is a glass protection to the lamp-room which alloy's the light to shine all round the coin pass. Tlie four knees, set in piirs with a strip of brpss separating them, each pair diametrically opposite, are, of course, of ginss, and it is through them that the concentrated rays are transmitted. The prisms^ which occupy the spaces between the lenses in the circular lantern, aie aLo of stass, ve^ no light beyond a few, comparatively faint, prismatic colours can. be seen. It is all reflected inwards into the powerful lenses. In order to meet the focusced light from these lenses the eye of the observer at sea must look full into each lens as it revolves. The braes strip between catises the five-second interval of darkness, for as it passes the eye can see neither lens. Half a revolution of tho lantern occupies 30 seconds of time, then the opposite pair of lenses emit their double flash in passing, so that at whatever point of the compass the observer is the double flash is seen by him. In the glow of the ' approaching daw n the power of the light begins to diminish, though it spins and flashes desperately, baffron beams stretch upwards to the zenith and the outlines of the hills- are clear-cut against the growing light. From saffron to palest green, from green to pink, to crimson, to gold — the dawn comes timidly, fearful of the dark. There is a sudden silence which thrills the ear like a new sound ; the lantern has ceased revolving. The bright-armed dawn, laying a shinina hand upon it, bids it be still. The light is extinguished : the prisms and lenses which tossed its radiance to the ends of the world are fla«liinp; and glittering in chromntic colours induced by the sunlight which is streaming upon them. The vigil of the night is over.