Masters of Space by Walter Kellogg Towers
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Walter Kellogg Towers >> Masters of Space
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[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.
Marconi had instructed his operator at Poldhu to send simply the
letter "s" at an hour corresponding to 12.30 A.M. in Newfoundland.
Great was the excitement and suspense in Cornwall when the hour for
the test arrived. Forgetting that they were sleepy, the staff crowded
about the sending key, and the little building at the foot of the
ring of great masts supporting the aerial shook with the crash of the
blinding sparks as the three, dots which form the letter "s" were sent
forth. Even greater was the tension on the Newfoundland coast, where
Marconi sat eagerly waiting for the signal. Finally it came, three
faint ticks in the telephone receiver. The wireless had crossed the
Atlantic. Marconi had no sending apparatus, so that it was not until
the cable had carried the news that those in England knew that the
message had been received.
Because Marconi had never made a statement or a claim he had not been
able to prove, he had attained a reputation for veracity which made
his statement that he had received a signal across the Atlantic carry
weight with the scientists. Many, of course, were skeptical, and
insisted that the simple signal had come by chance from some ship not
far away. But the inventor pushed quietly and steadily ahead, making
arrangements to perfect the system and establish it so that it would
be of commercial use.
Marconi returned to England, but two months later set out for America
again on the liner _Philadelphia_ with improved apparatus. He kept in
constant communication with his station at Poldhu until the ship was
a hundred and fifty miles from shore. Beyond that point he could not
send messages, as the sending apparatus on the ship lacked sufficient
power. Messages were received, however, until the sending station
was over two thousand miles away. This seemed miraculous to those
on shipboard, but Marconi accepted it as a matter of course. He had
equipped the Poldhu station to send twenty-one hundred miles, and he
knew that it should accomplish the feat.
A large station was set up at Cape Breton, Nova Scotia, and regular
communication was established between there and Poldhu. With the
establishment of regular transatlantic communication the utility of
Marconi's invention, even for work at great distances, was no longer
open to question. By quiet, unassuming, conscientious work he had put
another great carrier of messages at the service of the world, and he
now reaped the fame and fortune which he so richly deserved.
XVIII
THE WIRELESS SERVES THE WORLD
Marconi Organized Wireless Telegraphy Commercially--The New Wonder
at the Service of the World--Marine Disasters Prevented--The
Extension of the Wireless on Shipboard--Improved Apparatus--The
Wireless in the World War--The Boy and the Wireless.
With his clear understanding of the possibilities of his invention,
Marconi was not long in establishing the wireless upon a commercial
basis. He is a man of keen business judgment, and as he brought his
invention forward and clearly demonstrated its worth at a time when
commercial enterprise was alert he found no great difficulty in
establishing his company. The first Marconi company was organized
as early as 1897 under the name of the Wireless Telegraph and Signal
Company, Limited. This was later displaced by the Marconi Telegraph
Company, which operates a regular system of stations on a commercial
basis, carrying messages in competition with the cable and telegraph
companies. It also erects stations for other companies which are
operated under the Marconi patents.
With the telegraph and the telephone so well established and serving
the needs of ordinary communication on land, it was natural that the
wireless should make headway but slowly as a commercial proposition
between points on land. For communication at sea, however, it had no
competition, and merchant-ships as well as war vessels were rapidly
equipped with wireless apparatus.
When the great liner _Republic_ was sinking as a result of a collision
off the port of New York in 1903 her wireless brought aid. Her
passengers and crew were taken off in safety, and what otherwise would
have been a terrible disaster was avoided by the use of the wireless.
The utility of the wireless was again brought sharply to the attention
of the world. It was realized that a wireless set on a passenger-ship
was necessary if the lives of the passengers were to be safeguarded.
The United States Government by its laws now requires that
passenger-ships shall be equipped with wireless apparatus in charge of
a competent operator.
One of the early objections made to the wireless was its apparent lack
of secrecy, since any other receiving apparatus within range of the
waves sent forth by the sending station can receive the signals. It
was also realized that as soon as any considerable number of stations
were established about the world, and began sending messages to and
fro, there would be a perfect jumble of waves flying about in all
directions through the ether, so that no messages could be sent or
received.
Marconi's answer to these difficulties was the tuning apparatus. The
electric waves carrying the messages may be sent out at widely varying
lengths. Marconi found that it was possible to adjust a receiving
station so that it would receive only waves of a certain length.
Thus stations which desired to communicate could select a certain
wave-length, and they could send and receive messages without
interfering with others using different wave-lengths, or without the
receiving station being confused by messages coming in from
other stations using different wave-lengths. You know that when a
tuning-fork is set in vibration another of the same pitch near it will
vibrate with it, but others of different pitch will not be affected.
The operation of wireless stations in tune with each other is similar.
[Illustration: A REMARKABLE PHOTOGRAPH TAKEN OUTSIDE OF THE CLIFDEN
STATION WHILE MESSAGES WERE BEING SENT ACROSS TO CAPE RACE
The camera was exposed for two hours, and the white bars show the
sparks leaving the wires for their journey through the air for
seventeen hundred miles.]
[Illustration: MARCONI STATION AT CLIFDEN, IRELAND
These dynamos send a message straight across the ocean.]
An example of the value of tuning is afforded by the manner in which
press reports are sent from the great Marconi station at Poldhu. Each
night at a certain hour this station sends out news reports of the
events of the day, using a certain set wave-length. Each ship on the
Atlantic and every land station within range which is to receive the
reports at that hour adjusts its receiving set to receive waves of
that length. In this way they hear nothing but the Poldhu news reports
which they desire to receive, and are not troubled by messages from
other stations within range.
Secrecy is also attained by the use of tuning. It is possible that
another station may discover the wave-length being used for a secret
message and "listen in," but there are so many possible wave-lengths
that this is difficult. Secrecy may also be secured by the use of code
messages.
Many of the advantages of tuning were lost by the international
agreement which provided that but two wave-lengths should be used for
commercial work. This, however, enables ships to get in touch with
other ships in time of need. With his telephone receivers the operator
can hear the passage of the waves as they are brought to him by his
aerial and the dots and dashes sound as buzzes of greater or less
length. Out of the confusion of currents passing through the air he
can select the messages he wishes to read by sound.
You may wonder how one wireless operator gets into communication with
another. He first listens in to determine whether messages are coming
through the ether within range in the wave-length he is to use.
Hearing nothing, he adjusts his sending apparatus to the desired
wave-length and switches this in with the signal aerial which
serves both his sending and his receiving set. This at the same time
disconnects his receiving set. He sends out the call letters of the
station to which he wishes to send a message, following them with
his own call letters, as a signature to show who is calling. After
repeating these signals several times he switches out his sending set
and listens in with his receiving set. If he then gets an answer from
the other station he can begin sending the message.
Marconi was not allowed to hold the wireless field unmolested.
Many others set up wireless stations, some of them infringing upon
Marconi's patents. Others have devised wireless systems along
more original lines. Particularly we should mention two American
experimenters, Dr. de Forest and Professor Fessenden. Both have
established wireless systems with no little promise. The system of
Professor Fessenden is especially unique and original and may be
destined to work a revolution in the methods of wireless telegraphy.
With an increase in the number of wireless stations and varieties
of apparatus came a wide increase in the uses to which wireless
telegraphy was applied. We have already noticed the press service
from Poldhu. The British Government makes use of this same station to
furnish daily news to its representatives in all parts of the
world. The wireless is also used to transmit the time from the great
observatories.
Some of the railroads in the United States have equipped their trails
as well as their stations with wireless sets. It has proved its worth
in communicating between stations, taking the place in time of need
of either the telegraph or the telephone. In equipping the trains with
sets a difficulty was met in arranging the aerials. It is, of course,
impossible to arrange the wires at any height above the cars, since
they would be swept away in passing under bridges. Even with very low
aerials, however, communication has been successfully maintained at
a distance of over a hundred miles. The speed of the fastest train
affects the sending and receiving of messages not at all. It was also
found that messages passed without hindrance, even though the train
was passing through a tunnel.
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