The Sea: Its Stirring Story of Adventure, Peril, & Heroism Volume II Part 12

CHAPTER XI.

THE LIGHTHOUSE (_continued_).

The Bell Rock-The good Abbot of Arberbrothok-Ralph the Rover-Rennie's grand Lighthouse-Perils of the Work-Thirty-two Men apparently doomed to Destruction-A New Form of Outward Construction-Its successful Completion-The Skerryvore Lighthouse and Alan Stevenson-Novel Barracks on the Rock-Swept Away in a Storm-The Unshapely Seal and Unfortunate Cod-Half-starved Workmen-Out of Tobacco-Difficulties of Landing the Stones-Visit of M. de Quatref.a.ges to Hehaux-Description of the Lighthouse Exterior-How it Rocks-Practice _versus_ Theory-The Interior-A Parisian Apartment at Sea.

Some eleven miles eastward from the mainland of Scotland, near the entrances to the Firths of Forth and Tay, lies an extensive ledge of very dangerous rocks, nearly two miles in length. This sunken reef was a source of much peril to the unfortunate sailors driven too near its nearly hidden dangers, and early in the fourteenth century the Abbot of Arbroath, or Arberbrothok, caused a bell to be placed upon the princ.i.p.al rock, so that-

"When the Rock was hid by the surge's swell, The mariners heard the warning bell; And then they knew the perilous Rock, And blessed the Abbot of Arberbrothok."

Southey has, in his ballad of "The Inchcape Rock," immortalised the tradition(56) that a notorious pirate cut the bell from the rock-

"Down sank the bell with a gurgling sound, The bubbles arose and burst around; Quoth Sir Ralph, 'The next who comes to the Rock, Won't bless the Abbot of Arberbrothok.'"

And so the rover sailed away, and grew rich with plundered store, till at length he thought of Scotland once again, and turned his vessel's head for home. He approached her coasts in haze and fog, and knew he could not be far from the rocky sh.o.r.e.

"They hear no sound, the swell is strong; Though the wind hath fallen they drift along, Till the vessel strikes with a s.h.i.+vering shock,- 'Oh, Christ! it is the Inchcape Rock!'

"Sir Ralph the Rover tore his hair; He curst himself in his despair; The waves rush in on every side, The s.h.i.+p is sinking beneath the tide."

Nothing was done to replace the bell or set a beacon on the reef until the beginning of the present century, when, after many plans had been discussed, John Rennie was ordered by the Board of Commissioners to examine the site and report on the subject generally. He recommended a substantial stone lighthouse, similar to that on the Eddystone. Although the Inchcape Rock was not so long uncovered by the tide as the former, after a few courses had been laid, there would be no greater delay in completing the building. The Commissioners obtained from Parliament the requisite powers in 1806; Rennie was appointed engineer, with Robert Stevenson as a.s.sistant engineer.

The whole of the year 1807 was occupied in constructing the necessary vessels for conveying the stones, and in erecting suitable machinery and building shops at Arbroath, which was fixed upon as the most convenient point on the coast for carrying on the land operations. Some progress was made on the rock itself, where a smith's forge was erected and a temporary beacon raised, while a floating light, fitted up on an old fis.h.i.+ng-boat, was anch.o.r.ed near the reef until the lighthouse could be completed. During the short period in which the rocks were uncovered or unexposed to the fury of the waves, some progress was made with the excavations for the foundations. The dangerous nature of the employment may be ill.u.s.trated by the following brief account of an accident which happened to the workmen on the 2nd of September, before the excavation for the first course of stones had been completed. An additional number of masons had that morning come off from Arbroath in the tender named the _Smeaton_, in honour of the engineer of the Eddystone, and had landed them safely on the rock. The vessel rode off at some distance. The wind rising, the men began to be uneasy as to the security of the _Smeaton's_ cables, and a party went off in a boat to examine whether she was secure, but before they could reach the vessel's side they found she had already gone adrift, leaving the greater part of the men upon the reef in the face of a rising tide.

By the time the _Smeaton's_ crew had got her mainsail set, and made a tack towards their companions, she had drifted about three miles to leeward, with both wind and tide against her, and it was clear that she could not possibly make the rock until long after it had been completely covered.

There were thirty-two men in all on the rock, provided with but two boats, capable of carrying only twenty-four persons in fine weather. Mr.

Stevenson seems to have behaved with great coolness and presence of mind; though he afterwards confessed that of the two feelings of hope and despair the latter largely predominated. Fully persuaded of the perils of the situation, he kept his fears to himself, and allowed the men to continue their occupations of boring and excavating.

"After working for about three hours, the water began to rise along the lower parts of the foundations, and the men were compelled to desist. The forge-fire became extinguished; the smith ceased from hammering at the anvil, and the masons from hewing and boring; and when they took up their tools to depart, and looked around, their vessel was not to be seen, and the third of their boats had gone after the _Smeaton_, which was drifting away in the distance! Not a word was uttered, but the danger of their position was comprehended by all. They looked towards their master in silence; but the anxiety which had been growing in his mind for some time had now become so intense that he was speechless. When he attempted to speak, he was so parched that his tongue refused utterance. Turning to one of the pools on the rock, he lapped a little water, which gave him relief, though it was salt; but what was his happiness when, on raising his head, some one called out, 'A boat! a boat!' and sure enough a large boat was seen through the surge making for them. She proved to be the Bell Rock pilot-boat, which had come off from Arbroath with letters, and her timely arrival doubtless saved the lives of the greater part of the workmen. They were all taken off and landed in safety, though completely drenched and exhausted."

Rennie, accompanied by one of his sons, visited the rock on the 5th of October, 1807, the day before the works were suspended for the winter.

They came off from Arbroath, and stayed on board the lighthouse-yacht all night, where Stevenson met him, and has recorded the delightful conversations held on general and professional matters. On the following morning Rennie landed, amidst great _eclat_ and a display of all the available colours, to inspect the progress made. The whole party, workmen and all, returned to sh.o.r.e for the season that day.

The preparation of the stone blocks occupied next winter, and by the spring large numbers were ready and were floated off. In May, 1808, the excavations on the rock were continued, and on the 10th of July the first stone was laid with considerable ceremony. By the last week of November three courses of masonry had been laid. By the end of 1809 the tower had been built to a height of thirty feet, and was almost secure from the fury of the waves. "In his report to the commissioners he stated that he found that the form of slope which he had adopted for the base of the tower, as well as the curve of the building, fully answered his expectations-that they presented comparatively small obstructions to the roll of the waves, which played round the column with ease." The curve of this tower at the base is much greater than that of the Eddystone. The Bell Rock Lighthouse was completed by the end of 1810, and the light was regularly exhibited after the 1st of February, 1811. Counting to the top of the lantern, it is 127 feet high. It may here be remarked that in many works the credit of designing and building this lighthouse has been given to Robert Stevenson, the resident engineer. Rennie, however, has the only rightful claim to be so considered; he acted throughout as chief engineer, furnished the design down to the pettiest details, settled the kind of stone and other materials to be used, down even to the mortar and mode of mixing it.

Another work of great labour and difficulty was the erection of a lighthouse on the Skerryvore Rocks, which lie twelve miles W.S.W. of the Isle of Tyree in Argylls.h.i.+re, and were formerly the scene of numerous wrecks. The operations were commenced in 1838, the architect being Alan Stevenson, son of the Robert Stevenson who was employed on the Bell Rock Lighthouse. The engineer gave the world a succinct account(57) of the difficulties, dangers, and successful issue of the undertaking.

[Ill.u.s.tration: LIGHTHOUSE ON THE INCHCAPE ROCK.]

The actual construction of the lighthouse had no very remarkable points of difference with the works of Smeaton or Rennie. Stevenson built a rather novel structure on the rock as a temporary barrack for the workmen. It consisted of a wooden tower perched upon a triangular framework, under which was an open gallery, the floor of which was removed at the end of each season, so as to allow free s.p.a.ce for the pa.s.sage of the sea during the storms of winter, but on which, during summer, they kept the stock of coals, the tool-chest, the beef and beer casks, and other smaller material, which they could not, even at that season of the year, leave on the rock itself. Next came the kitchen and provision-store, a six-sided apartment about twelve feet in diameter, and somewhat more than seven feet high, in which small s.p.a.ce-curtailed as it was by the seven beams which pa.s.sed through it-stood a caboose, capable of cooking for forty men, and various cupboards and lockers lined with tin, for holding biscuits, meal and flour, &c. The next storey held two apartments: one for Mr. Stevenson, in which he had his hammock, desk, chair and table, books and instruments.

The top storey was surmounted by a pyramidal roof, and was lined with four tiers of berths, capable of accommodating thirty people. The framework was erected on a part of the rock as far removed as possible from the proposed foundation of the lighthouse tower; but in a great gale which occurred on the 3rd of November it was entirely destroyed and swept from the rock, nothing remaining to point out its site but a few broken and twisted iron stanchions, and attached to one of them a piece of a beam, so shaken and rent by das.h.i.+ng against the rock as literally to resemble a bunch of laths. Thus did one night obliterate the traces of a season's toil, and blast the hopes which the workmen fondly cherished of a stable dwelling on the rock, and of refuge from the miseries of sea-sickness, which the experience of the season had taught many of them to dread more than death itself. A more successful attempt was subsequently made, and the second erection braved the storm for several years after the works were finished.

"Perched forty feet above the wave-beaten rock," says Stevenson, "in this singular abode, the writer of this little volume(58) has spent many a weary day and night at those times when the sea prevented any one going down to the rock, anxiously looking for supplies from the sh.o.r.e, and earnestly longing for a change of weather favourable to the re-commencement of the works. For miles around nothing could be seen but white foaming breakers, and nothing heard but howling winds and las.h.i.+ng seas. At such seasons most of our time was spent in bed; for there alone we had effectual shelter from the winds and the spray, which searched every cranny in the walls of the barrack. Our slumbers, too, were at times fearfully interrupted by the sudden pouring of the sea over the roof, the rocking of the house on its pillars, and the spirting of water through the seams of the doors and windows: symptoms which, to one suddenly aroused from sound sleep, recalled the appalling fate of the former barrack, which had been engulfed in the foam not twenty yards from our dwelling, and for a moment seemed to summon us to a similar fate. On two occasions, in particular, those sensations were so vivid as to cause almost every one to spring out of bed; and some of the men flew from the barrack by a temporary gangway to the more stable but less comfortable shelter afforded by the bare wall of the lighthouse tower, then unfinished, where they spent the remainder of the night in the darkness and the cold."

Yet life on the Skerryvore was by no means dest.i.tute of its peculiar pleasures. The grandeur of the ocean's rage, the deep murmur of the waves, the hoa.r.s.e cry of the sea-birds, were varied by peaceful hours, when the sea was gla.s.sy and the deep blue vault of heaven was studded with a thousand stars. "Among the many wonders of the 'great deep,'" says Stevenson, "which we witnessed at the Skerryvore, not the least is the agility and power displayed by the unshapely seal. I have often seen half a dozen of these animals round the rock, playing on the surface or riding on the crests of curling waves, come so close as to permit us to see their eyes and head, and lead us to expect that they would be thrown _high and dry_ at the foot of the tower; when suddenly they performed a somersault within a few feet of the rock, and diving into the flaky and wreathing foam, disappeared, and as suddenly re-appeared a hundred yards off, uttering a strange low cry."

On one occasion the tender could not come off to the poor people on the rock for seven weeks. The seamen pa.s.sed a most dreary time. Their provisions and fuel were short; their clothes were worn to rags; and, what was to them of more importance still, they _were out of tobacco_!

One of the great difficulties experienced was landing the stones on the rock from the lighters, which, towed out by a steamer, were cast off as near the landing-place as possible and then towed in by boats. The landing service throughout the whole progress of the works was one of danger and anxiety, and many narrow escapes were made. On many occasions the men who steered the lighters ran great risks, and it was often found necessary to lash them to the rails, to prevent them being thrown overboard by the sudden bounds of the vessels, or being carried away by the weight of water which swept their decks as they were towed through a heavy sea. Sometimes they were forced, owing to the heavy seas which threatened to throw the vessels on the top of the rock, to draw out the lighters from the wharf without landing a single stone, after they had been towed through a stormy pa.s.sage of thirteen miles. One day, during the very best part of the season, so sudden were the jerks of the vessel before the sea, that eight large warps, or cables, were snapped like threads, and the lighter was carried violently before a crested wave which rolled unexpectedly upon her. Those who stood on deck were thrown flat on their faces, and imagined that the vessel had been laid high and dry on the top of the rock. Yet, in spite of the short season and great difficulties of the work, no less than 120 lighters were towed out and discharged in the summer and autumn of 1841. During the progress of building the lighthouse, cranes and other materials were swept away by the waves, and daily risks were run in blasting the splintery gneiss, or by the falling of heavy bodies from the tower on the narrow s.p.a.ce below, to which so many persons were necessarily confined. Yet no loss of life or limb occurred; and "our remarkable preservation was viewed," says Stevenson, "as in a peculiar manner the gracious work of Him by whom 'the very hairs of our head are all numbered.'"

The light was first exhibited on the 1st of February, 1844. It is a revolving apparatus, and the light appears at its brightest state once in every minute. The lantern is no less than 150 feet above the sea, and its flashes may be seen from the deck of a vessel eighteen miles off. It is frequently seen from the high land of Barra, distant thirty-eight miles.

The ma.s.s of stonework is double that of the Bell Rock Lighthouse, and five times that of the Eddystone; it measures 58,580 cubic feet. The Skerryvore Light-tower was erected at a cost of 86,977 17s. 7d.

[Ill.u.s.tration: THE SKERRYVORE LIGHTHOUSE.]

The eminent French naturalist, M. de Quatref.a.ges, has given us an admirable description(59) of a visit paid by him to the lighthouse of Hehaux, on a rock near the Isles of Brehat, off the coast of Brittany. He says, after some very beautiful remarks on the contemplation of nature, and its alleviation of the worst heart-sorrows: "Twilight often surprised me in the midst of my reveries, and often, too, the shades of night fell around me while I lay stretched beneath the star-bespangled deep azure canopy of heaven. I could then see another star s.h.i.+ning in the far distance, which had been lighted by the hand of man. From the position I had chosen I could recognise the beacon-towers of Hehaux, of which the seamen of the islands had spoken to me with the liveliest expressions of enthusiasm, and which I had frequently watched by day as it stood out like a black line drawn along the whitish background of the sky. I would not leave Brehat without visiting it. A few slight services had secured me the good-will of the officers of customs, who willingly consented to take me to Hehaux. Accordingly, one splendid day in October we left the harbour of La Corderie in a pinnace, manned by six st.u.r.dy seamen. The weather was splendid; not a cloud obscured the sky, which was reflected on the mirror-like surface of the ocean, whose depths it seemed to double.

Impelled by the combined action of a light wind, which swelled out two small square sails, and of the rapid current imparted to the waters of Kerpont by the force of the tide, our pinnace shot across the waves as a sledge glides over the snow. Sometimes, indeed, we pa.s.sed through a whirling eddy, which shook every part of our frail craft, and betrayed the vicinity of some submarine rock; but we soon regained the unruffled sea, and without having taken cognisance of the rapid rate at which we were moving, we saw Brehat sink below the distant horizon behind us, whilst rock after rock and islet after islet seemed at every moment to emerge from the waves towards which we were advancing.... The nearer we drew to Hehaux the taller seemed the beacon-tower, which stood forth from the tower, with its lofty granite column and gla.s.s lantern, protected by that magical rod which is able to attract and safely conduct to earth the destructive force of the thunderbolt. We landed, and at once began our inspection of this colossal block, which has been upreared by the hand of man on the Epees de Treguier, which, once the dread of the seaman, have become his protecting guides through the storms and darkness of night.

"The Hehaux Lighthouse would be regarded as a most remarkable monument even in our princ.i.p.al towns, but standing, as it does, alone in the midst of the ocean, it acquires by its very isolation a character of severe grandeur, which impresses the mind most powerfully. Figure to yourself a wall of granite, where the current and the storm do not even permit the hardiest ferns to take root, with here and there a twisted and deeply wave-worn ma.s.s projecting beyond the rest of the rocky ledge. It is here that the architect has laid the foundation of the tower. The base, which is of a conical form, is surmounted by a circular gallery. The lower portion curves gracefully outwards, spreading over the ground like the root of some colossal marine plant springing up from the foundation stones, which have been inserted far within the rock. On this base, which measures about twenty yards across, rises a column twenty-six feet in diameter, surmounted by a second gallery, whose supports and stone bal.u.s.trades call to mind the portcullis and battlements of some feudal donjon. From the summit to the base this part of the edifice is composed of large blocks of whitish granite, arranged in regular strata, and carefully dove-tailed into one another. As far as a third of the height of the building the rows of stones are bound together by granite joggles, which at the same time penetrate into the two superposed stones. The stones have been cut and arranged with such precision that there has been hardly any reason for using cement, which has only been employed in filling up a few imperceptible voids: and hence the lighthouse, from the base to the summit, seems to form one solid block, which is more h.o.m.ogeneous and probably more compact than the rocks which support it. The platform which crowns this magnificent column, at an elevation of more than 140 feet above high tide watermark, is surmounted by a stone cupola, at once solid and graceful, supported by pillars which are separated by large panes of gla.s.s. It is within this frame of gla.s.s that the beacon is lighted, which may be distinctly seen from every direction at a distance of twenty-seven miles.

"At low tide the sea leaves a s.p.a.ce of several hundred square yards uncovered round the base of the edifice; at high tide it entirely surrounds it. It is then that the tower of Hehaux rises in its solemn isolation from the midst of the waves, as if it were a standard of defiance upraised by the genius of man against the demon of the tempest.

At times one might almost fancy that the heavens and the sea, conscious of the outrage offered to them, were leagued together against the enemy, which seems to brave them by its imperturbability. The north-west wind roars round the tower, darkening its thick gla.s.s windows with torrents of rain and drifts of snow and hail. These impetuous blasts bear along with them from the far-spread ocean colossal waves, whose crests not unfrequently reach the first gallery, but these fluid ma.s.ses slide away from the round and polished surfaces of the granite, which leave them no points of adhesion, and darting their long lines of foam above the cupola, they break with thundering roar against the rocks of Stallio-Bras or the boulders of Sillon. The tower supports these terrific a.s.saults without injury, although it bends, as if in homage, before the might of its foes.

I was a.s.sured by the keepers that during a violent storm the oil in the lamps of the highest rooms presents a variation of level exceeding an inch, which would lead us to a.s.sume that the summit of the tower describes an arc of about a yard in extent. This very flexibility seems, however, in itself a proof of durability. At all events, we meet with similar conditions in several monuments, which for ages have braved the inclemency of recurring seasons. The spire of Strasburg Cathedral, in particular, bends its long ogives and slender pinnacles beneath the force of the winds, while the cross on its summit oscillates at an elevation of more than 450 feet above the ground.

"To construct a monument on these rocks, which seemed the very focus of all the storms which raged on that part of our coasts, was like building an edifice in the open sea. Such a project must, indeed, have appeared at first sight almost impracticable. After their third season of labour, the workmen completed the foundations of the tower and fixed the key-stone of the cupola. In vain did difficulties of every kind combine with the winds and waves to oppose the work; human industry has come forth victorious from the struggle, and although a thousand difficulties and dangers beset the labourers, no serious accident to them or their work troubled the joy of their triumph. Only on one occasion was science at fault. In order to facilitate the arrival of the stones, which had to be brought from a distance of several leagues, and cut at Brehat, the skilful engineer who had furnished all the plans and superintended their execution wished to construct a wooden pier for the disembarkation of the stones at the spot where they were required. Several of the older seamen objected to the plan as impracticable, but M. Reynaud, who was not familiar with the sea, and who, moreover, was proud of having stemmed the current of rapid rivers, trusted to the stability of his ma.s.sive piles, clamped together with iron and bronze. But he was soon compelled to admit his mistake. The first storm sufficed to scatter over the waters the whole of these ponderous and solid materials like so many pieces of straw. So a crane was attached to the summit of a rock, to which boats could be moored, and the materials for building were then drawn up to a railway which had been thrown over the precipice that separated this natural landing-place from the site of the tower.

"Now that we have admired the exterior of the lighthouse, follow me into the interior by the help of these steps, which have been formed by the insertion of bars of copper into the stone. Let us pause for a moment to admire the ponderous bronze doors which hermetically seal the entrance, before we plunge into those vaults which look as if they had been cut out of the solid rock. We are in the first storey, surrounded by stores of wood and ropes and workmen's tools. Above, we perceive cases of zinc, which, we are told, contain oil to feed the lamps and water for the use of the men employed in the building. In the third storey is the kitchen, with its pantry and larder, on a level with the first gallery. We need not enter the three apartments appropriated to the use of the men, for, beyond being very simple and clean, there is nothing to record concerning them.

But we have now reached the seventh storey, and we must rest for a few moments in the little octagonal saloon, set apart for the engineers, when they come to inspect the condition of the lighthouse. Here, in the midst of the ocean, more than a hundred feet above the level of the sea, you will find the comfort and almost the elegance of a Parisian apartment.

"Let us now return to the spiral staircase which has brought us thus far, and which will carry us at once to the portion of the edifice which is more particularly destined to fulfil the special purpose for which the tower is designed. The eighth storey contains vessels of oil, gla.s.ses, revolving lamps, some admirable instruments intended for meteorological observations, a thermometer, barometer, and chronometer. Here the spiral staircase terminates in a flattened arch, which supports a slender pillar, cut into steps, which are the only means of communication with the watch-tower above, in which the men take it by turns to keep guard every night. You will be surprised on looking round to perceive that this apartment is coated with different coloured marbles, which line the walls and vaulted roof, and even cover the floor. But this luxury, which may appear to you so much out of place, has been introduced from necessity.

The apparatus for lighting the building enters the room through a circular aperture in the ceiling, and hence the most extreme cleanliness becomes necessary, which could alone be obtained by the aid of perfectly polished surfaces."

The tenth and last flight of steps brings one beneath the cupola, and to the machinery by which a light of the first order is maintained.

CHAPTER XII.

THE LIGHTHOUSE (_concluded_).

Lighthouses on Sand-Literally screwed down-The Light on Maplin Sands-That of Port Fleetwood-Iron Lighthouses-The Lanterns themselves-Eddystone long Illuminated with Tallow Candles-Coal Fires-Revolution caused by the invention of the Argand Burner-Improvements in Reflectors-The Electric Light at Sea-Flas.h.i.+ng and Revolving Lights-Coloured Lights-Their Advantages and Disadvantages-Lanterns obscured by Moths, Bees, and Birds.

The difficulties involved in constructing a lighthouse on solid rock have been shown, and it was at one time thought absolutely impossible to erect-with any prospect of permanent duration-one upon storm-exposed sands. _Nous avons change tout cela._ It is no longer necessary to place floating lights in places of great danger, although for other reasons they are constantly used. One of the greatest modern triumphs of engineering is Mitch.e.l.l's screw-mooring apparatus. To describe it fully would necessitate several pages of technical matter. Suffice it to say that enormous cast-iron screws, having hollow cylindrical centres, through which wrought-iron spindles pa.s.s, are literally screwed down into the sand, or its substratum of other soil. One of the earliest experiments was made on the verge of the Maplin Sand, at the mouth of the Thames. Nine of the mooring-screws were inserted into the sand 21 feet, one in the centre, the rest forming an octagon 42 feet in circ.u.mference, having standards or posts which stood 5 feet above the surface of the sand. A raft of timber was floated over the spot, and a capstan in its centre drove the screws to the required depth. This raft was afterwards sunk, by covering it with 200 tons of rough stone. Two years were allowed to elapse, at the termination of which time the whole ma.s.s was found firmly embedded, and then a lighthouse, raised on a strong open framework, was erected over this sub-structure. During these long preparations a very similar structure was commenced and finished at Port Fleetwood, on the River Wyre, near Lancaster.

The preparatory steps were similar to those already described. The foundation of the lighthouse was formed of seven screw-piles, six of them occupying the angles of a hexagon 46 feet in diameter, the seventh being in the centre. From each screw proceeds a pile 15 feet in length, having at the upper end another screw for securing a wooden column. These columns are of Baltic timber, the one in the centre being 56 feet, the others 46 feet in length, firmly secured with iron hoops and coated with pitch. The platform, upon which the house stands, is 27 feet in diameter, the house itself being 20 feet in diameter and 9 feet high. From the summit of the house rises a twelve-sided lantern, 10 feet in diameter and 8 feet high.

Altogether the light is elevated about 46 feet above low-water level, and ranges over an horizon of eight miles. The light is of the dioptric kind-bright, steady, and uniform, and when the weather is too foggy to allow it to be seen, a bell is tolled by machinery, to give the needful warning.

At the period when screw-pile lighthouses were being thus successfully erected, other and most valuable suggestions were being made for the building of bronze and cast-iron lighthouses. The great advantage of iron over stone and other materials in those portions of the building not actually in contact with sea-water soon became apparent. Upon a given base a much larger internal capacity could be obtained; plates could be cast in large surfaces and with few joints, and a system of binding adopted which should ensure the perfect combination of every part. The comparatively small bulk and weight also of the component parts gave great facilities for the transport and rapid construction of such structures. The initial cast-iron lighthouse was designed by Mr. Gordon in 1840, and was cast and put together within three months from the date of the contract. It was then taken to pieces and s.h.i.+pped for Jamaica, on which island it now lights up Morant Point, a point of great danger. The Commissioners of the House of a.s.sembly had applied to Mr. Gordon to supply a suitable lighthouse at the smallest possible cost, and in furnis.h.i.+ng them with the structure of cast-iron he fulfilled their wishes admirably, the expense not exceeding one-third of the cost of a similar building in stone. This elegant lighthouse, the outline of which resembles that of the Celtic towers of Ireland, was exhibited to visitors while it stood complete in the contractor's premises. The diameter of the tower is 18 feet 6 inches at the base, diminis.h.i.+ng to 11 feet under the cap. The tower is formed of nine tiers of iron plates, each tier being 10 feet high and about three-quarters of an inch thick. At the base of the structure eleven plates are required to form the circ.u.mference, at the top nine plates; they are cast with a f.l.a.n.g.e around their inner edges, and when put together these f.l.a.n.g.es form the joints, which are fastened together with nut-and-screw bolts and caulked with iron cement. The interior of the tower, to the height of 27 feet, was to be filled up with masonry and concrete of the weight of 300 tons; the remainder is divided into store-rooms and berths for the attendants. The tower is finished by an iron railing, within which rises the light-room, also of cast-iron, with windows of plate-gla.s.s. A copper roof and a short lightning-rod complete the whole. The Admiralty notice announced the exhibition of this light on Morant Point November 1st, 1842, and stated that the elevation of the light is 97 feet above the level of the sea, and that in clear weather it is visible at a distance of twenty-one miles. The light is of the revolving kind, consisting of fifteen Argand lamps and reflectors, five in each side of an equilateral triangle, and so placed as to produce a continuous light, but with periodical flashes. The tower is painted white, and the lower portion is coated with coal-tar to preserve it from rust. It rests on a granite base, and is also cased with granite near the foundation, the more certainly to prevent the action of the sea-water on the metal.

While the engineer had attained some of his greatest triumphs in the construction of lighthouses, the optician had not once directed his attention to the invention of a brilliant light, worthy to be placed upon the structure which proudly rose high above the fierce waves with the strength and solidity of a rock. During a period of forty years after the completion of the Eddystone tower by Smeaton, the lantern was illuminated by tallow candles stuck in hoops, just as a stand or booth is lighted at a country fair, and so lately as the year 1811 it was lighted with twenty-four wax candles. In 1812 the Lizard Light was maintained with coal fires; and in 1816, when the Isle of May Light, in the Firth of Forth, was taken possession of by the Commissioners of the Northern Lighthouses, a coal fire was exhibited in a _chauffer_-a description of light which had been exhibited for 181 years. In 1801 the light at Harwich, in addition to the coal fire, had a _flat_ plate of rough bra.s.s on the landward side, to serve as a reflector. Such methods of lighting were of course very deficient in power, and did not enable the mariner to distinguish one light from another-a point which is often of as much importance as the brilliancy of the light itself. Prior to the invention of the Argand lamp (about 1784) the production of a strong and brilliant light from a single source was scarcely possible, and even such a lamp, by its una.s.sisted powers, would not be of very great value in giving early notice to the mariner of his approach to the coast, which ought to be the primary object of a lighthouse. As the rays of a luminous body proceed in all directions in straight lines, it is obvious that in the case of a single lamp the mariner would derive benefit only from that small portion of light which proceeded from the centre of the flame to his eye. The other rays would proceed to other parts of the horizon, or escape upwards to the sky, or downwards to the earth, and thus be of no value to him. By increasing the number of burners a small portion of light from each burner would slightly increase the effective action, but by far the greater portion of the light produced would escape uselessly above and below the horizon and also at the back of each flame. Next, these defects were remedied, and the efficiency of the light greatly increased, by placing behind each lamp a reflector of such a form as to collect the rays that would otherwise be lost, and throw them forward to the horizon. The adoption of such a method has led to what is called the catoptric system of lights.