search for the wireless. He grounded his wires and sent high currents
into the earth, but improved his system and took another step toward
the final achievement by adding a large induction coil to his sending
equipment. He suggested that the spoken word might be sent as well as
dots and dashes, and so sought the wireless telephone as well as
the wireless telegraph. Like his predecessors, his experiments were
successful only at short distances.
The next application of the induction telegraph was to establish
communication with moving trains. Several experimenters had suggested
it, but it remained for Thomas A. Edison to actually accomplish it.
He set up a plate of tin-foil on the engine or cars, opposite the
telegraph wires. Currents could be induced across the gap, no matter
what the speed of the train, and, traveling along the wires to the
station, communication was thus established. Had Edison continued his
investigation further, instead of turning to other pursuits, he
might have achieved the means of communicating through the air at
considerable distances.
These experiments by Americans in the early 'eighties seemed to
promise that America was to produce the wireless telegraph, as it had
produced the telegraph and the telephone. But the greatest activity
now shifted to Europe and the American men of science failed to push
their researches to a successful conclusion. Sir W.H. Preece,
an Englishman, brought himself to public notice by establishing
communication with the Isle of Wight by Morse's method. Messages were
sent and received during a period when the cable to the island was
out of commission, and thus telegraphing without wires was put to
practical use.
Preece carried his experiments much further. In 1885 he laid out two
great squares of insulated wire, a quarter of a mile to the side,
and at a distance of a quarter of a mile from each other. Telephonic
communication was established between them, and thus he had attained
wireless telephony by induction. In 1887, another Englishman, A.W.
Heaviside, laid circuits over two miles long on the surface and other
circuits in the galleries of a coal-mine three hundred and fifty feet
below, and established communication between the circuits. Working
together, Preece and Heaviside extended the distances over which
they could communicate. Preece finally decided that a combination of
conduction and induction was the best means of wireless communication.
He grounded the wire of his circuit at two points and raised it to a
considerable height between these points. Preece's work was to put the
theories of Professor Trowbridge to practical use and thus bring the
final achievement a step nearer.
But conduction and induction combined would not carry messages to a
distance that would enable extensive communication. A new medium had
yet to be found, and this was the work of Heinrich Hertz, a young
German scientist. He was experimenting with two flat coils of wire,
as had many others before him, but one of the coils had a small gap
in it. Passing the discharge from a condenser into this coil, Hertz
discovered that the spark caused when the current jumped the gap set
up electrical vibrations that excited powerful currents in the other
coil. These currents were noticeable, though the coils were a very
considerable distance apart. Thus Hertz had found out how to send out
electrical waves that would travel to a considerable distance.
What was the medium that carried these waves? This was the question
that Hertz asked himself, and the answer was, the ether. We know that
light will pass through a vacuum, and these electric waves would do
likewise. It was evident that they did not pass through the air. The
answer, as evolved by Hertz and approved by other scientists, is that
they travel through the ether, a strange substance which pervades all
space. Hertz discovered that light and his electrical waves traveled
at the same speed, and so deduced that light consists of electrical
vibrations in the ether.
With the knowledge that this all-pervading ether would carry electric
waves at the speed of light, that the waves could be set up by the
discharge of a spark across a spark-gap in a coil, and that they
could be received in another coil in resonance with the first, the
establishment of a practical wireless telegraph was not far away.
XVI
AN ITALIAN BOY'S WORK
The Italian Youth who Dreamed Wonderful Dreams--His Studies--Early
Detectors--Marconi Seeks an Efficient Detector--Devises New Sending
Methods--The Wireless Telegraph Takes Form--Experimental Success.
With the nineteenth century approaching its close, man had discovered
that the electric waves would travel through the ether; he had learned
something of how to propagate those waves, and something of how
to receive them. But no one had yet been able to combine these
discoveries in practical form, to apply them to the task of carrying
messages, to make the improvements necessary to make them available
for use at considerable distances. Though many mature scientists had
devoted themselves to the problem, it remained for a youth to solve
it. The youth was Guglielmo Marconi, an Italian.
We have noticed that the telegraph, the cable, and the telephone were
the work of those of the Anglo-Saxon race--Englishmen or Americans--so
it came as a distinct surprise that an Italian youth should make
the next great application of electricity to communication. But
Anglo-Saxon blood flows in Marconi's veins. Though his father was an
Italian, his mother was an Irishwoman. He was born at Villa Griffone
near Bologna, Italy, on April 25, 1874. He studied in the schools of
Bologna and of Florence, and early showed his interest in scientific
affairs. From his mother he learned English, which he speaks as
fluently as he does his native tongue. As a boy he was allowed to
attend English schools for short periods, spending some time at
Bedford and at Rugby.
One of his Italian teachers was Professor Righi, who had made a close
study of the Hertzian waves, and who was himself making no small
contributions to the advancement of the science. From him young
Marconi learned of the work which had been accomplished, and of the
apparatus which was then available. Marconi was a quiet boy--almost
shy.
He did not display the aggressive energy so common with many promising
youths. But though he was quiet, he was not slothful. He entered into
his studies with a determination and an application that brought to
him great results. He was a student and a thinker. Any scientific book
or paper which came before him was eagerly devoured. It was this habit
of careful and persistent study that made it possible for Marconi to
accomplish such wonderful things at an early age.
Marconi had learned of the Hertzian waves. It occurred to him that by
their aid wireless telegraphy might be accomplished. The boy saw the
wonderful possibilities; he dreamed dreams of how these waves might
carry messages from city to city, from ship to shore, and from
continent to continent without wires. He realized his own youth and
inexperience, and it seemed certain to him that many able scientists
had had the same vision and must be struggling toward its attainment.
For a year Marconi dreamed those dreams, studying the books and papers
which would tell him more of these wonderful waves. Each week he
expected the news that wireless telegraphy had been established, but
the news never came. Finally he concluded that others, despite their
greater opportunities, had not been so far-seeing as he had thought.
Marconi attacked the problem himself with the dogged persistence and
the studious care so characteristic of him. He began his experiments
upon his father's farm, the elder Marconi encouraging the youth and
providing him with funds with which to purchase apparatus. He set
up poles at the opposite sides of the garden and on them mounted the
simple sending and receiving instruments which were then available,
using plates of tin for his aerials. He set up a simple spark-gap, as
had Hertz, and used a receiving device little more elaborate. A Morse
telegraph-key was placed in circuit with the spark-gap. When the key
was held down for a longer period a long spark passed between the
brass knobs of the spark-gap and a dash was thus transmitted. When
the key was depressed for a shorter period a dot in the Morse code was
sent forth. After much work and adjustment Marconi was able to send
a message across the garden. Others had accomplished this for similar
distances, but they lacked Marconi's imagination and persistence, and
failed to carry their experiments further. To the young Irish-Italian
this was but a starting-point.
[Illustration: GUGLIELMO MARCONI
Photographed in the uniform of an officer in the Italian army]
Marconi quickly found that the receiver was the least effective part
of the existing apparatus. The waves spread in all directions from
the sending station and become feebler and feebler as the distance
increases. To make wireless telegraphy effective over any considerable
distance a highly efficient and extremely sensitive receiving device
is necessary. Some special means of detecting the feeble currents was
necessary. The coherer was the solution. As early as 1870 a Mr. S.A.
Varley, an Englishman, had discovered that when he endeavored to
send a current through a mass of carbon granules the tiny particles
arranged themselves in order under the influence of the electric
current, and offered a free path for the passage of the current. When
shaken apart they again resisted the flow of current until it became
powerful enough to cause them to again arrange themselves into a
sort of bridge for its passage. Thus was the principle of the coherer
discovered.
An Italian scientist, Professor Calzecchi-Onesti, carried these
experiments still further. He used various substances in place of the
carbon granules and showed that some of them will arrange themselves
so as to allow the passage of a current under the influence of the
spark setting up the Hertzian waves. Professor E. Branly, of the
Catholic University of Paris, took up this work in 1890. He arranged
metal filings in a small glass tube six inches long and arranged a
tapper to disarrange the filings after they had been brought together
under the influence of the spark.
With the Branly coherer as the basis Marconi sought to make
improvements which would result in the detector he was seeking. For
his powder he used nickel, mixed with a small proportion of fine
silver filings. This he placed between silver plugs in a small glass
tube. Platinum wires were connected to the silver plugs and brought
out at the opposite ends of the tube. It required long study to
determine just how to adjust the plugs between which the powder was
loosely arranged. If the particles were pressed together too tightly
they would not fall apart readily enough under the influence of the
tapper. If too much space was allowed they would not cohere readily
enough. Marconi also discovered that a larger proportion of silver
in the powder and a smaller amount between the plugs increased the
sensitiveness of the receiver. Yet he found it well not to have it
too sensitive lest it cohere for every stray current and so give false
signals.
Under the influence of the electric waves set up from the spark-gap
those tiny particles so arranged themselves that they would readily
carry a current between the plugs. By placing these plugs with their
platinum terminals in circuit with a local battery the current from
this local battery was given a passage through the coherer by the
action of the electric waves coming through the ether. While these
waves themselves were too feeble to operate a receiving mechanism,
they were strong enough to arrange the particles of the sensitive
metal in the tube in order, so that the current from the local battery
could pass through them. This current operated a telegraph relay which
in turn operated a Morse receiving instrument. An electrical tapper
was also arranged in this circuit so that it would strike the tube a
light blow after each long or short wave representing a dot or a dash
had been received. Thus the particles were disarranged, ready to array
themselves when the next wave came through the ether and so form the
bridge over which the stronger local circuit could convey the signal.
Marconi further discovered that the most effective arrangement was to
run a wire from one terminal of the coherer into the ground, and from
the other to an elevated metal plate or wire. The waves coming through
the ether were received by the elevated wire and were conducted down
to the coherer. Experimenting with his apparatus on the posts in
the garden, he discovered that an increase in the height of the wire
greatly increased the receiving distance.
At his sending station he used the exciter of his teacher, Professor
Righi. This, too, he modified and perfected for his practical purpose.
As he used the device it consisted of two brass spheres a millimeter
apart. An envelope was provided so that the sides of the spheres
toward each other and the space between was occupied by vaseline oil
which served to keep the faces of the spheres clean and produce a more
uniform spark. Outside the two spheres, but in line with them, were
placed two smaller spheres at a distance of about two-fifths of a
centimeter. The terminals of the sending circuit were attached to
these. The secondary coil of a large induction coil was placed in
series with them, and batteries were wired in series with the primary
of the coil with a sending key to make and break the circuit. When the
key was closed a series of sparks sprang across the spark-gap, and
the waves were thus set up in the ether and carried the message to the
receiving station.
As in the case of his receiving station, Marconi found that results
were much improved when he wired his sending apparatus so that one
terminal was grounded and the other connected with an elevated wire or
aerial, which is now called the antenna. By 1896 Marconi had brought
this apparatus to a state of perfection where he could transmit
messages to a distance of several miles. This Irish-Italian youth
of twenty-two had mastered the problem which had baffled veteran
scientists and was ready to place a new wonder at the service of the
world.
The devices which Marconi thus assembled and put to practical use had
been, in the hands of others, little more than scientific toys.
Others had studied the Hertzian waves and the methods of sending and
detecting them from a purely scientific viewpoint. Marconi had the
vision to realize the practical possibilities, and, though little
more than a boy, had assembled the whole into a workable system of
communication. He richly deserves the laurels and the rewards as the
inventor of the wireless telegraph.
XVII
WIRELESS TELEGRAPHY ESTABLISHED
Marconi Goes to England--he Confounds the Skeptics--A Message to
France Without Wires--The Attempt to Span the Ocean--Marconi in
America Receives the First Message from Europe--Fame and Recognition
Achieved.
The time had now come for Marconi to introduce himself and his
discoveries to the attention of the world. He went to England, and
on June 2, 1896, applied for a patent on his system of wireless
telegraphy. Soon afterward his plans were submitted to the
postal-telegraph authorities. Fortunately for Marconi and for the
world, W.H. Preece was then in authority in this department. He
himself had experimented with some little success with wireless
messages. He was able enough to see the merit in Marconi's
discoveries and generous enough to give him full recognition and every
encouragement.
The apparatus was first set up in the General Post-office in London,
another station being located on the roof but a hundred yards away.
Though several walls intervened, the Hertzian waves traversed them
without difficulty, and messages were sent and received. Stations
were then set up on Salisbury Plain, some two miles apart, and
communication was established between them.
Though the postal-telegraph authorities received Marconi's statements
of his discoveries with open mind and put his apparatus to fair tests,
the public at large was much less tolerant. The skepticism which met
Morse and Bell faced Marconi. Men of science doubted his statements
and scoffed at his claims. The Hertzian waves might be all right to
operate scientific playthings, they thought, but they were far too
uncertain to furnish a medium for carrying messages in any practical
way. Then, as progress was made and Marconi began to prove his system,
the inevitable jealousies arose. Experimenters who might have invented
the wireless telegraph, but who did not, came forward to contest
Marconi's claims and to seek to snatch his laurels from him.
The young inventor forged steadily ahead, studying and experimenting,
devising improved apparatus, meeting the difficulties one by one
as they arose. In most of his early experiments he had used a
modification of the little tin boxes which had been set up in his
father's garden as his original aerials. Having discovered that the
height of the aerials increased the range of the stations, he covered
a large kite with tin-foil and, sending it up with a wire, used this
as an aerial. Balloons were similarly employed. He soon recognized,
however, that a practical commercial system, which should be capable
of sending and receiving messages day and night, regardless of the
weather, could not be operated with kites or balloons. The height of
masts was limited, so he sought to increase the range by increasing
the electrical power of the current sending forth the sparks from the
sending station. Here he was on the right path, and another long step
forward had been taken.
In the fall of 1897 he set up a mast on the Isle of Wight, one hundred
and twenty feet high. From the top of this was strung a single wire
and a new series of experiments was begun. Marconi had spent the
summer in Italy demonstrating his apparatus, and had established
communication between a station on the shore and a war-ship of the
Italian Navy equipped with his apparatus. He now secured a small
steamer for his experiments from his station on the Isle of Wight and
equipped it with a sixty-foot mast. Communication was maintained with
the boat day after day, regardless of weather conditions. The distance
at which communication could be maintained was steadily increased
until communication was established with the mainland.
In July of 1898 the wireless demonstrated its utility as a conveyer of
news. An enterprising Dublin newspaper desired to cover the Kingstown
regatta with the aid of the wireless. In order to do this a land
station was erected at Kingstown, and another on board a steamer which
followed the yachts. A telephone wire connected the Kingstown station
with the newspaper office, and as the messages came by wireless from
the ship they were telephoned to Dublin and published in successive
editions of the evening papers.
This feat attracted so much attention that Queen Victoria sought the
aid of the wireless for her own necessities. Her son, the Prince of
Wales, lay ill on his yacht, and the aged queen desired to keep
in constant communication with him. Marconi accordingly placed one
station on the prince's yacht and another at Osborne House, the
queen's residence. Communication was readily maintained, and one
hundred and fifty messages passed by wireless between the prince and
the royal mother.
While the electric waves bearing the messages were found to pass
through wood, stone, or earth, it was soon noticed in practical
operation that when many buildings, or a hill, or any other solid
object of size intervened between the stations the waves were
greatly retarded and the messages seriously interfered with. When the
apparatus was placed on board steel vessels it was found that any part
of the vessel coming between the stations checked the communication.
Marconi sought to avoid these difficulties by erecting high aerials at
every point, so that the waves might pass through the clear air over
solid obstructions.
Marconi's next effort was to connect France with England. He went to
France to demonstrate his apparatus to the French Government and set
up a station near Boulogne. The aerial was raised to a height of one
hundred and fifty feet. Another station was erected near Folkestone
on the English coast, across the Channel. A group of French officials
gathered in the little station near Folkestone for the test, which was
made on the 27th of March, 1899. Marconi sent the messages, which were
received by the station on the French shore without difficulty. Other
messages were received from France, and wireless communication between
the nations was an accomplished fact.
The use of the wireless for ships and lighthouses sprang into favor,
and wireless stations were established all around the British coasts
so that ships equipped with wireless might keep in communication
with the land. The British Admiralty quickly recognized the value
of wireless telegraphy to war vessels. While field telegraphs and
telephones had served the armies, the navies were still dependent upon
primitive signals, since a wire cannot be strung from ship to ship
nor from ship to shore. So the British battle-ships were equipped with
wireless apparatus and a thorough test was made. A sham battle
was held in which all of the orders were sent by wireless, and
communication was constantly maintained both between the flag-ships
and the vessels of their fleets and between the flag-ships and the
shore. Marconi's invention had again proved itself.
The wireless early demonstrated its great value as a means of saving
life at sea. Lightships off the English coast were equipped with the
wireless and were thus enabled to warn ships of impending storms,
and on several occasions the wireless was used to summon aid from the
shore when ships were sinking because of accidents near the lightship.
Following the establishment of communication with France, Marconi
increased the range of his apparatus until he was able to cover most
of eastern Europe. In one of his demonstrations he sent messages
to Italy. His ambition, however, was to send messages across the
Atlantic, and he now attacked this stupendous task. On the coast of
Cornwall, England, he began the construction of a station which should
have sufficient power to send a message to America. Instead of using
a single wire for his aerial, he erected many tall poles and strung a
number of wires from pole to pole. The comparatively feeble batteries
which had furnished the currents used in the earlier efforts were
replaced with great power-driven dynamos, and converters were used
instead of the induction coil. Thus was the great Poldhu station
established.
Late in 1901 Marconi crossed to America to superintend the
preparations there, and that he himself might be ready to receive
the first message, should it prove possible to span the ocean. Signal
Hill, near St. John's, Newfoundland was selected as the place for the
American station. The expense of building a great aerial for the test
was too great, and so dependence was had upon kites to send the wires
aloft. For many days Marconi's assistants struggled with the great
kites in an effort to get them aloft. At last they flew, carrying the
wire to a great height. The wire was carried into a small Government
building near by in which Marconi stationed himself. At his ear was a
telephone receiver, this having been substituted for the relay and the
Morse instrument because of its far greater sensitiveness.