Boys' Second Book of Inventions

The reflector system being impracticable for long-distance work, Mr. Marconi experimented with tuning. He so constructed a receiver that it responds only to a certain transmitter. That is, if the transmitter is radiating 800,000 vibrations a second, the corresponding receiver will take only 800,000 vibrations. In exactly the same way a familiar tuning fork will respond only to another tuning fork having exactly the same "tune," or number of vibrations per second. And Mr. Marconi has now succeeded in bringing this tuning system to some degree of perfection, though very much work yet remains to be done. For instance, in one of his English experiments, at Poole in England, he had two receivers connected with the same wire, and tuned to different transmitters located at St. Catherine's Point. Two messages were sent, one in English and one in French. Both were received at the same time on the same wire at Poole, but one receiver rolled off its message in English, the other in French, without the least interference. And so when critics suggested that the inventor may have been deceived at St. John's by messages transmitted from ocean liners, he was able to respond promptly:

"Impossible. My instrument was tuned to receive only from my station in Cornwall."

Indeed, the only wireless-telegraph apparatus that could possibly have been within hundreds of miles of Newfoundland would be one of the Marconi-fitted steamers, and the "call" of a steamer is not the letter "S," but "U."

The importance of the new system of tuning can hardly be overestimated. By it all the ships of a fleet can be provided with instruments tuned alike, so that they may communicate freely with one another, and have no fear that the enemy will read the messages. The spy of the future must be an electrical expert who can slip in somehow and steal the secret of the enemy's tunes. Great telegraph companies will each have its own tuned instruments, to receive only its own messages, and there may be special tunes for each of the important governments of the world. Or perhaps (for the system can be operated very cheaply) the time will even come when the great banking and business houses, or even families and friends, will each have its own wireless system, with its own secret tune. Having variations of millions of different vibrations, there will be no lack of tunes. For instance, the British navy may be tuned to receive only messages of 700,000 vibrations to the second, the German navy 1,500,000, the United States Government 1,000,000, and so on indefinitely.

Tuning also makes multiplex wireless telegraphy a possibility; that is, many messages may be sent or received on the same suspended wire. Supposing, for instance, the operator was sending a hurry press despatch to a newspaper. He has two transmitters, tuned differently, connected with his wire. He cuts the despatch in two, sends the first half on one transmitter, and the second on the other, thereby reducing by half the time of transmission.

A sort of impression prevails that wireless telegraphy is still largely in the uncertain experimental stage; but, as a matter of fact, it has long since passed from the laboratory to a wide commercial use. Its development since Mr. Marconi's first paper was read, in 1896, and especially since the first message was sent from England to France across the Channel in March, 1899, has been astonishingly rapid. Most of the ships of the great navies of Europe and all the important ocean liners are now fitted with the "wireless" instruments. The system has been recently adopted by the Lloyds of England, the greatest of shipping exchanges. It is being used on many lightships, and the New York Herald receives daily reports from vessels at sea, communicated from a ship station off Nantucket. Were there space to be spared, many incidents might be told showing in what curious and wonderful ways the use of the "wireless" instruments has saved life and property, to say nothing of facilitating business.

And it cannot now be long before a regular telegraph business will be conducted between Massachusetts and England, through the new stations. Mr. Marconi informed me that he would be able to build and equip stations on both sides of the Atlantic for less than $150,000, the subsequent charge for maintenance being very small. A cable across the Atlantic costs between $3,000,000 and $4,000,000, and it is a constant source of expenditure for repairs. The inventor will be able to transmit with single instruments about twenty words a minute, and at a cost ridiculously small compared with the present cable tolls. He said in a speech delivered at a dinner given him by the Governor at St. John's that messages which now go by cable at twenty-five cents a word might be sent profitably at a cent a word or less, which is even much cheaper than the very cheapest present rates in America for messages by land wires. It is estimated that about $400,000,000 is invested in cable systems in various parts of the world. If Marconi succeeds as he hopes to succeed, much of the vast network of wires at the bottom of the world's oceans, represented by this investment, will lose its usefulness. It is now the inventor's purpose to push the work of installation between the continents as rapidly as possible, and no one need be surprised if the year 1902 sees his system in practical operation. Along with this transatlantic work he intends to extend his system of transmission between ships at sea and the ports on land, with a view to enabling the shore stations to maintain constant communication with vessels all the way across the Atlantic. If he succeeds in doing this, there will at last be no escape for the weary from the daily news of the world, so long one of the advantages of an ocean voyage. For every morning each ship, though in mid-ocean, will get its bulletin of news, the ship's printing-press will strike it off, and it will be served hot with the coffee. Yet think what such a system will mean to ships in distress, and how often it will relieve the anxiety of friends awaiting the delayed voyager.

Mr. Marconi's faith in his invention is boundless. He told me that one of the projects which he hoped soon to attempt was to communicate between England and New Zealand. If the electric waves follow the curvature of the earth, as the Newfoundland experiments indicate, he sees no reason why he should not send signals 6,000 or 10,000 miles as easily as 2,000.

Then there is the whole question of the use of wireless telegraphy on land, a subject hardly studied, though messages have already been sent upward of sixty miles overland. The new system will certainly prove an important adjunct on land in war-time, for it will enable generals to signal, as they have done in South Africa, over comparatively long distances in fog and storm, and over stretches where it might be impossible for the telegraph corps to string wires or for couriers to pass on account of the presence of the enemy.

CHAPTER VIII

SEA-BUILDERS

The Story of Lighthouse Building – Stone-tower Lighthouses, Iron Pile Lighthouses, and Steel Cylinder Lighthouses

A sturdy English oak furnished the model for the first of the great modern lighthouses. A little more than one hundred and forty years ago John Smeaton, maker of odd and intricate philosophical instruments and dabbler in mechanical engineering, was called upon to place a light upon the bold and dangerous reefs of Eddystone, near Plymouth, England. John Smeaton never had built a lighthouse; but he was a man of great ingenuity and courage, and he knew the kind of lighthouse not to build; for twice before the rocks of Eddystone had been marked, and twice the mighty waves of the Atlantic had bowled over the work of the builders as easily as they would have overturned a skiff. Winstanley, he of song and story, designed the first of these structures, and he and all his keepers lost their lives when the light went down; the other, the work of John Rudyerd, was burned to the water's edge, and one of the keepers, strangely enough, died from the effects of melting lead which fell from the roof and entered his open mouth as he gazed upward. Both of these lighthouses were of wood, and both were ornamented with balconies and bay-windows, which furnished ready holds for the rough handling of the wind.

John Smeaton walked in the woods and thought of all these problems. He tells quaintly in his memoirs how he observed the strength with which an oak-tree bore its great weight of leaves and branches; and when he built his lighthouse, it was wide and flaring at the base, like the oak, and deeply rooted into the sea-rock with wedges of wood and iron. The waist was tapering and cylindrical, bearing the weight of the keeper's quarters and the lantern as firmly and jauntily as the oak bears its branches. Moreover, he built of stone, to avoid the possibility of fire, and he dovetailed each stone into its neighbour, so that the whole tower would face the wind and the waves as if it were one solid mass of granite. For years Smeaton's Eddystone blinked a friendly warning to English mariners, serving its purpose perfectly, until the Brothers of Trinity saw fit to build a larger tower in its place.

In England the famous lighthouses of Bell Rock, built by Robert Stevenson, Skerryvore, and Wolf Rock are all stone towers; and in our own country, Minot's Ledge, off Boston Harbour, more difficult of construction than any of them, Spectacle Reef light in Lake Huron, and Stannard Rock light in Lake Superior are good examples of Smeaton's method of building.

The mighty stone tower still remains for many purposes the most effective method of lighting the pathways of the sea, but it is both exceedingly difficult to build, and it is very expensive. Within comparatively recent years busy inventors have thought out several new plans for lighthouses, which are quite as wonderful and important in their way as wireless telegraphy and the telephone are in the realm of electricity.

One of these inventions is the iron-pile or screw-pile lighthouse, and the other is the iron cylinder lighthouse. I will tell the story of each of them separately.

The skeleton-built iron-pile lighthouse bears much the same relation to the heavy stone tower lighthouse that a willow twig bears to a great oak. The latter meets the fury of wind and wave with stern resistance, opposing force to force; the former conquers its difficulties by avoiding them.

A completed screw-pile lighthouse has the odd appearance of a huge, ugly spider standing knee-deep in the sea. Its squat body is the home of the keeper, with a single bright eye of light at the top, and its long spindly legs are the iron piles on which the structure rests. Thirty years ago lighthouse builders were much pleased with the ease and apparent durability of the pile light. An Englishman named Mitchell had invented an iron pile having at the end a screw not unlike a large auger. By boring a number of these piles deep into the sand of the sea-bottom, and using them as the foundation for a small but durable iron building, he was enabled to construct a lighthouse in a considerable depth of water at small expense. Later builders have used ordinary iron piles, which are driven into the sand with heavy sledges. Waves and tides pass readily through the open-work of the foundation, the legs of the spider, without disturbing the building overhead. For Southern waters, where there is no danger of moving ice-packs, lighthouses of this type have been found very useful, although the action of the salt water on the iron piling necessitates frequent repairs. More than eighty lights of this description dot the shoals of Florida and adjoining States. Some of the oldest ones still remain in use in the North, notably the one on Brandywine shoal in Delaware Bay; but it has been found necessary to surround them with strongly built ice-breakers.

Two magnificent iron-pile lights are found on Fowey Rocks and American Shoals, off the coast of Florida, the first of which was built with so much difficulty that its story is most interesting.

Fowey Reef lies five miles from the low coral island of Soldier Key. Northern storms, sweeping down the Atlantic, brush in wild breakers over the reef and out upon the little key, often burying it entirely under a torrent of water. Even in calm weather the sea is rarely quiet enough to make it safe for a vessel of any size to approach the reef. The builders erected a stout elevated wharf and store-house on the key, and brought their men and tools to await the opportunity to dart out when the sea was at rest and begin the work of marking the reef. Before shipment, the lighthouse, which was built in the North, was set up, complete from foundation to pinnacle, and thoroughly tested.

At length the workmen were able to remain on the reef long enough to build a strong working platform twelve feet above the surface of the water, and set on iron-shod mangrove piles. Having established this base of operations in the enemy's domain, a heavy iron disk was lowered to the reef, and the first pile was driven through the hole at its centre. Elaborate tests were made after each blow of the sledge, and the slightest deviation from the vertical was promptly rectified with block and tackle. In two months' time nine piles were driven ten feet into the coral rock, the workmen toiling long hours under a blistering sun. When the time came to erect the superstructure, the sea suddenly awakened and storm followed storm, so that for weeks together no one dared venture out to the reef. The men rusted and grumbled on the narrow docks of the key, and work was finally suspended for an entire winter. At the very first attempt to make a landing in the spring, a tornado drove the vessels far out of their course. But a crew was finally placed on the working platform, with enough food to last them several weeks, and there they stayed, suspended between the sea and the sky, until the structure was complete. This lighthouse cost $175,000.

The famous Bug Light of Boston and Thimble Light of Hampton Roads, Va., are both good examples of the iron-pile lighthouse.

Now we come to a consideration of iron cylinder lighthouses, which are even more wonderful, perhaps, than the screw-piles, and in constructing them the sea-builder touches the pinnacle of his art.

Imagine a sandy shoal marked only by a white-fringed breaker. The water rushes over it in swift and constantly varying currents, and if there is a capful of wind anywhere on the sea, it becomes an instant menace to the mariner. The shore may be ten or twenty miles away, so far that a land-light would only lure the seaman into peril, instead of guiding him safely on his way. A lightship is always uncertain; the first great storm may drive it from its moorings and leave the coast unprotected when protection is most necessary. Upon such a shoal, often covered from ten to twenty feet with water, the builder is called upon to construct a lighthouse, laying his foundation in shifting sand, and placing upon it a building strong enough to withstand any storm or the crushing weight of wrecks or ice-packs.

It was less than twenty years ago that sea-builders first ventured to grapple with the difficulties presented by these off-shore shoals. In 1881 Germany built the first iron cylinder lighthouse at Rothersand, near the mouth of the Weser River, and three years later the Lighthouse Establishment of the United States planted a similar tower on Fourteen-Foot Banks, over three miles from the shores of Delaware Bay, in twenty feet of water. Since then many hitherto dangerous shoals have been marked by new lighthouses of this type.

When a builder begins a stone tower light on some lonely sea-rock, he says to the sea, "Do your worst. I'm going to stick right here until this light is built, if it takes a hundred years." And his men are always on hand in fair weather or foul, dropping one stone to-day and another to-morrow, and succeeding by virtue of steady grit and patience. The builder of the iron cylinder light pursues an exactly opposite course. His warfare is more spirited, more modern. He stakes his whole success on a single desperate throw. If he fails, he loses everything: if he wins, he may throw again. His lighthouse is built, from foundation caisson to lantern, a hundred or a thousand miles away from the reef where it is finally to rest. It is simply an enormous cast-iron tube made in sections or courses, each about six feet high, not unlike the standpipe of a village water-works. The builder must set up this tube on the shoal, sink it deep into the sand bottom, and fill it with rocks and concrete mortar, so that it will not tip over. At first such a feat would seem absolutely impossible; but the sea-builder has his own methods of fighting. With all the material necessary to his work, he creeps up on the shoal and lies quietly in some secluded harbour until the sea is calmly at rest, suspecting no attack. Then he darts out with his whole fleet, plants his foundation, and before the waves and the wind wake up he has established his outworks on the shoal. The story of the construction of one of these lighthouses will give a good idea of the terrible difficulties which their builders must overcome.

Not long ago W. H. Flaherty, of New York, built such a lighthouse at Smith's Point, in Chesapeake Bay. At the mouth of the Potomac River the opposing tides and currents have built up shoals of sand extending eight or ten miles out into the bay. Here the waves, sweeping in from the open Atlantic, sometimes drown the side-lights of the big Boston steamers. The point has a grim story of wrecks and loss of life; in 1897 alone, four sea-craft were driven in and swamped on the shoals. The Lighthouse Establishment planned to set up the light just at the edge of the channel, and 120 miles south of Baltimore.

Eighty thousand dollars was appropriated for doing the work. In August, 1896, the contractors formally agreed to build the lighthouse for $56,000, and, more than that, to have the lantern burning within a single year.

By the last of September a huge, unwieldy foundation caisson was framing in a Baltimore shipyard. This caisson was a bottomless wooden box, 32 feet square and 12 feet high, with the top nearly as thick as the height of a man, so that it would easily sustain the weight of the great iron cylinder soon to be placed upon it. It was lined and caulked, painted inside and out to make it air-tight and water-tight, and then dragged out into the bay, together with half an acre of mud and dock timbers. Here the workmen crowned it with the first two courses of the iron cylinder – a collar 30 feet in diameter and about 12 feet high. Inside of this a second cylinder, a steel air-shaft, five feet in diameter, rose from a hole in the centre of the caisson, this providing a means of entrance and exit when the structure should reach the shoal.

Upon the addition of this vast weight of iron and steel, the wooden caisson, although it weighed nearly a hundred tons, disappeared completely under the water, leaving in view only the great black rim of the iron cylinder and the top of the air-shaft.

On April 7th of the next year the fleet was ready to start on its voyage of conquest. The whole country had contributed to the expedition. Cleveland, O., furnished the iron plates for the tower; Pittsburg sent steel and machinery; South Carolina supplied the enormous yellow-pine timbers for the caisson; Washington provided two great barge-loads of stone; and New York City contributed hundreds of tons of Portland cement and sand and gravel, it being cheaper to bring even such supplies from the North than to gather them on the shores of the bay.

Everything necessary to the completion of the lighthouse and the maintenance of the eighty-eight men was loaded aboard ship. And quite a fleet it made as it lay out on the bay in the warm spring sunshine. The flagship was a big, double-deck steamer, 200 feet over all, once used in the coastwise trade. She was loaded close down to her white lines, and men lay over her rails in double rows. She led the fleet down the bay, and two tugs and seven barges followed in her wake like a flock of ducklings. The steamer towed the caisson at the end of a long hawser.

In three days the fleet reached the lighthouse site. During all of this time the sea had been calm, with only occasional puffs of wind, and the builders planned, somewhat exultantly, to drop the caisson the moment they arrived.

But before they were well in sight of the point, the sea awakened suddenly, as if conscious of the planned surprise. A storm blew up in the north, and at sunset on the tenth of April the waves were washing over the top of the iron cylinder and slapping it about like a boy's raft. A few tons of water inside the structure would sink it entirely, and the builder would lose months of work and thousands of dollars.

From a rude platform on top of the cylinder two men were working at the pumps to keep the water out. When the edge of the great iron rim heaved up with the waves, they pumped and shouted; and when it went down, they strangled and clung for their lives.

The builder saw the necessity of immediate assistance. Twelve men scrambled into a life-boat, and three waves later they were dashed against the rim of the cylinder. Here half of the number, clinging like cats to the iron plates, spread out a sail canvas and drew it over the windward half of the cylinder, while the other men pulled it down with their hands and teeth and lashed it firmly into place. In this way the cylinder shed most of the wash, although the larger waves still scuttled down within its iron sides. Half of the crew was now hurried down the rope-ladders inside the cylinder, where the water was nearly three feet deep and swashing about like a whirlpool. They all knew that one more than ordinarily large wave would send the whole structure to the bottom; but they dipped swiftly, and passed up the water without a word. It was nothing short of a battle for life. They must keep the water down, or drown like rats in a hole. They began work at sunset, and at sunrise the next morning, when the fury of the storm was somewhat abated, they were still at work, and the cylinder was saved.

The swells were now too high to think of planting the caisson, and the fleet ran into the mouth of the Great Wicomico River to await a more favourable opportunity. Here the builders lay for a week. To keep the men busy some of them were employed in mixing concrete, adding another course of iron to the cylinder, and in other tasks of preparation. The crew was composed largely of Americans and Irishmen, with a few Norwegians, the ordinary Italian or Bohemian labourer not taking kindly to the risks and terrors of such an expedition. Their number included carpenters, masons, iron-workers, bricklayers, caisson-men, sailors, and a host of common shovellers. The pay varied from twenty to fifty cents an hour for time actually worked, and the builders furnished meals of unlimited ham, bread, and coffee.

On April 17th, the weather being calmer, the fleet ventured out stealthily. A buoy marked the spot where the lighthouse was to stand. When the cylinder was exactly over the chosen site, the valves of two of the compartments into which it was divided were quickly opened, and the water poured in. The moment the lower edge of the caisson, borne downward by the weight of water, touched the shoal, the men began working with feverish haste. Large stones were rolled from the barges around the outside of the caisson to prevent the water from eating away the sand and tipping the structure over.

In the meantime a crew of twenty men had taken their places in the compartments of the cylinder still unfilled with water. A chute from the steamer vomited a steady stream of dusty concrete down upon their heads. A pump drenched them with an unceasing cataract of salt water. In this terrible hole they wallowed and struggled, shovelling the concrete mortar into place and ramming it down. Every man on the expedition, even the cooks and the stokers, was called upon at this supreme moment to take part in the work. Unless the structure could be sufficiently ballasted while the water was calm, the first wave would brush it over and pound it to pieces on the shoals.

After nearly two hours of this exhausting labour the captain of the steamer suddenly shouted the command to cast away.

The sky had turned black and the waves ran high. All of the cranes were whipped in, and up from the cylinder poured the shovellers, looking as if they had been freshly rolled in a mortar bed. There was a confused babel of voices and a wild flight for the steamer. In the midst of the excitement one of the barges snapped a hawser, and, being lightened of its load, it all but turned over in a trough of the sea. The men aboard her went down on their faces, clung fast, and shouted for help, and it was only with difficulty that they were rescued. One of the life-boats, venturing too near the iron cylinder, was crushed like an egg-shell, but a tug was ready to pick up the men who manned it.

So terrified were the workmen by the dangers and difficulties of the task that twelve of them ran away that night without asking for their pay.

On the following morning the builder was appalled to see that the cylinder was inclined more than four feet from the perpendicular. In spite of the stone piled around the caisson, the water had washed the sand from under one edge of it, and it had tipped part way over. Now was the pivotal point of the whole enterprise. A little lack of courage or skill, and the work was doomed.

The waves still ran high, and the freshet currents from the Potomac River poured past the shoals at the rate of six or seven miles an hour. And yet one of the tugs ran out daringly, dragging a barge-load of stone. It was made fast, and although it pitched up and down so that every wave threatened to swamp it and every man aboard was seasick, they managed to throw off 200 tons more of stone around the base of the caisson on the side toward which it was inclined. In this way further tipping in that direction was prevented, and the action of the water on the sand under the opposite side soon righted the structure.

Beginning on the morning of April 21st the entire crew worked steadily for forty-eight hours without sleeping or stopping for meals more than fifteen minutes at a time. When at last they were relieved, they came up out of the cylinder shouting and cheering because the foundation was at last secure.

The structure was now about thirty feet high, and filled nearly to the top with concrete. The next step was to force it down 15½ feet into the hard sand at the bottom of the bay, thus securing it for ever against the power of the waves and the tide. An air-lock, which is a strongly built steel chamber about the size of a hogshead, was placed on top of the air-shaft, the water in the big box-like caisson at the bottom of the cylinder was forced out with compressed air, and the men prepared to enter the caisson.

No toil can compare in its severity and danger with that of a caisson worker. He is first sent into the air-lock, and the air-pressure is gradually increased around him until it equals that of the caisson below; then he may descend. New men often shout and beg pitifully to be liberated from the torture. Frequently the effect of the compressed air is such that they bleed at the ears and nose, and for a time their heads throb as if about to burst open.

In a few minutes these pains pass away, the workers crawl down the long ladder of the air-shaft and begin to dig away the sand of the sea-bottom. It is heaped high around the bottom of a four-inch pipe which leads up the air-shaft and reaches out over the sea. A valve in the pipe is opened and the sand and stones are driven upward by the compressed air in the caisson and blown out into the water with tremendous force. As the sand is mined away, the great tower above it slowly sinks downward, while the subterranean toilers grow sallow-faced, yellow-eyed, become half deaf, and lose their appetites.

When Smith's Point Light was within two feet of being deep enough the workmen had a strange and terrible adventure.