had left his factory in Newark in charge of a capable superintendent,
and moved his own laboratories to Menlo Park, a quiet place about
twenty-five miles from Newark. His striking discoveries soon earned
for him the nickname of “The Wizard of Menlo Park.” Here he
experimented with the new apparatus known as the telephone. He said of
his own connection with it, “When I struck the telephone business the
Bell people had no transmitter, but were talking into the magneto
receiver. You never heard such a noise and buzzing as there was in
that old machine! I went to work and monkeyed around, and finally
struck the notion of the lampblack button. The Western Union Telegraph
Company thought this was a first-rate scheme, and bought the thing
out, but afterward they consolidated, and I quit the telephone
business.” As a matter of fact Edison has done a great deal of other
work besides inventing his carbon transmitter in the telephone field,
and the Patent Office is well stocked with applications he has sent
them for receivers and transmitters of different designs.
Edison has himself told of the main incidents in his perfection of the
electric light. In the _Electrical Review_ he said, “In 1878 I went
down to see Professor Barker, at Philadelphia, and he showed me an arc
lamp--the first I had seen. Then a little later I saw another--I think
it was one of Brush’s make--and the whole outfit, engine, dynamo, and
one or two lamps, was traveling around the country with a circus. At
that time Wallace and Moses G. Farmer had succeeded in getting ten or
fifteen lamps to burn together in a series, which was considered a
very wonderful thing. It happened that at the time I was more or less
at leisure, because I had just finished working on the carbon-button
telephone, and this electric-light idea took possession of me. It was
easy to see what the thing needed: it wanted to be subdivided. The
light was too bright and too big. What we wished for was little
lights, and a distribution of them to people’s houses in a manner
similar to gas. Grovernor P. Lowry thought that perhaps I could
succeed in solving the problem, and he raised a little money and
formed the Edison Electric Light Company. The way we worked was that I
got a certain sum of money a week and employed a certain number of
men, and we went ahead to see what we could do.
“We soon saw that the subdivision never could be accomplished unless
each light was independent of every other. Now it was plain enough
that they could not burn in series. Hence they must burn in multiple
arc. It was with this conviction that I started. I was fired with the
idea of the incandescent lamp as opposed to the arc lamp, so I went to
work and got some very fine platinum wire drawn. Experiment with this,
however, resulted in failure, and then we tried mixing in with the
platinum about ten per cent. of iridium, but we could not force that
high enough without melting it. After that came a lot of
experimenting--covering the wire with oxide of cerium and a number of
other things.
“Then I got a great idea. I took a cylinder of zirconia and wound
about a hundred feet of the fine platinum wire on it coated with
magnesia from the syrupy acetate. What I was after was getting a
high-resistance lamp, and I made one that way that worked up to forty
ohms. But the oxide developed the phenomena now familiar to
electricians, and the lamp short-circuited itself. After that we went
fishing around and trying all sorts of shapes and things to make a
filament that would stand. We tried silicon and boron, and a lot of
things that I have forgotten now. The funny part of it was that I
never thought in those days that a carbon filament would answer,
because a fine hair of carbon was so sensitive to oxidation. Finally,
I thought I would try it because we had got very high vacua and good
conditions for it.
“Well, we sent out and bought some cotton thread, carbonized it, and
made the first filament. We had already managed to get pretty high
vacua, and we thought, maybe, the filament would be stable. We built
the lamp and turned on the current. It lit up, and in the first few
breathless minutes we measured its resistance quickly and found it was
275 ohms--all we wanted. Then we sat down and looked at that lamp. We
wanted to see how long it would burn. The problem was solved--if the
filament would last. The day was--let me see--October 21, 1879. We sat
and looked, and the lamp continued to burn, and the longer it burned
the more fascinated we were. None of us could go to bed, and there was
no sleep for any of us for forty hours. We sat and just watched it
with anxiety growing into elation. It lasted about forty-five hours,
and then I said, If it will burn that number of hours now, I know I
can make it burn a hundred.’ We saw that carbon was what we wanted,
and the next question was what kind of carbon. I began to try various
things, and finally I carbonized a strip of bamboo from a Japanese
fan, and saw that I was on the right track. But we had a rare hunt
finding the real thing. I sent a schoolmaster to Sumatra and another
fellow up the Amazon, while William H. Moore, one of my associates,
went to Japan and got what we wanted there. We made a contract with an
old Jap to supply us with the proper fibre, and that man went to work
and cultivated and cross-fertilized bamboo until he got exactly the
quality we required.”
This is the inventor’s own statement, but it gives a very meagre
notion of the many months’ experimenting in his workshop while he
hunted for a suitable filament for his electric light.
As he said, after he had first seen the Brush light, and studied it,
he decided that the main problem was one of distribution, and
thereupon considered whether he should use the incandescent or the
voltaic arc in the system he was planning. At last he decided in favor
of the incandescent light.
Then began the long months of testing platinum wire. He wanted to find
some way of preventing this hardest of all metals from melting when
the full force of the electric current was turned into it. He worked
out several devices to keep the platinum from fusing, an automatic
lever to regulate the electric current when the platinum was near the
melting-point, and a diaphragm with the same object; but all of them
had to be discarded. Although he was still searching for the right
clue he seems to have had no doubt of his final success. He said at
this time, “There is no difficulty about dividing up the current and
using small quantities at different points. The trouble is in finding
a candle that will give a pleasant light, not too intense, which can
be turned off and on as easily as gas. Such a candle cannot be made
from carbon points, which waste away, and must be regulated constantly
while they do last. Some composition must be discovered which will be
luminous when charged with electricity and that will not wear away.
Platinum wire gives a good light when a certain quantity of
electricity is passed through it. If the current is made too strong,
however, the wire will melt. I want to get something better.”
It was generally known that Edison was working along this line. An
English paper, commenting on the matter, said, “The weak point of the
lamp is this, that in order to be luminous, platinum must be heated
almost to the point of melting. With a slight increase in the current,
the lamp melts in the twinkling of an eye, and in practice the
regulator is found to short-circuit the current too late to prevent
the damage. It is this difficulty which must be overcome. Can it be
done?”
After long study Edison concluded that pure platinum was not suited to
successful electric lighting. Then he incorporated with it another
material of a non-conducting nature, with the result that when the
electric current was turned on one material became incandescent and
the other luminous. This gave a clear, but not a permanent, light. He
tried many different combinations, and experimented month after month,
but none of his trials produced the result he wanted, and at last he
concluded that he was on the wrong track, and that neither platinum
nor any other metal would give the right light.
There is something very dramatic about his real discovery. He was
sitting in his laboratory one evening, when his right hand happened to
touch a small pile of lampblack and tar that his assistants had been
using in working on a telephone transmitter. He picked up a little of
it, and began to roll it between his finger and thumb. He was thinking
of other things, and he rolled the mixture absent-mindedly for some
time, until he had formed a thin thread that looked something like a
piece of wire. Glancing at it, he fell to wondering how it would serve
as a filament for his light. It was carbon, and might be able to stand
a stronger current than platinum. He rolled some more of the mixture,
and decided to try it.
His experiments had already resulted in the production of an almost
absolute vacuum, only one-millionth part of an atmosphere being left
in the tube. Such a vacuum had never been obtained before. With his
assistant, Charles Bachelor, he put a thread of the lampblack and tar
in a bulb, exhausted the air, and turned on the current. There was an
intense glow of light; but it did not last, the carbon soon burned
out. Therefore he started to study the reason why the carbon had
failed to withstand the electric current. His conclusion was that it
was impossible to get the air out of the lampblack. Besides that the
thread became so brittle that the slightest shock to the lamp broke
it. But he felt certain now that a carbon filament, made of something
other than tar and lampblack, was what he wanted.
He next sent a boy to buy a reel of cotton, and told his assistants he
was going to see what a carbonized thread would do. They looked
doubtful, but began the experiment. A short piece of the thread was
bent in the form of a hairpin, laid in a nickel mould and securely
clamped, and then put in a muffle furnace, where it was kept for five
hours. Then it was taken out and allowed to cool. The mould was opened
and the carbonized thread removed. It instantly broke. Another thread
was put through the same process. As soon as it was taken from the
mould it broke. Then a battle began that lasted for two days and two
nights, the object of which was to get a carbonized thread that would
not break. Edison wanted that thread because it contained no air, and
might stand a greater current than the lampblack. Finally they took
from the mould an unbroken thread, but as they tried to fasten it to
the conducting wire it broke into pieces. Only on the night of the
third day of their work, in all which time they had taken no rest, did
they get a thread safely into the lamp, exhaust the air, and turn on
the current. A clear, soft light resulted, and they knew that they had
solved the problem of the incandescent light.
Edison and Bachelor watched that light for hours. They had turned on a
small current at the start, to test the strength of the filament, but
as it stood it, they turned on a greater and greater current until the
thread was bearing a heat that would have instantly melted the
platinum wire. The cotton thread glowed for forty-five hours, and then
suddenly went out. The two watchers ended their long vigil, exhausted,
but very happy. They knew that they had found the light that was to be
the main illumination for the world.
But Edison realized that he had not yet found the ideal filament. The
cotton thread had only lasted forty-five hours, and he wanted one that
would burn for a hundred hours or longer. He wanted a more homogeneous
material than thread, and he began to try carbonizing everything he
could lay his hands on, straw, paper, cardboard, splinters of wood. He
found that the cardboard stood the current better than the cotton
thread, but even that did not burn long enough. Then he happened upon
a bamboo fan, tore off the rim, and tried that. It made a filament
that gave better results than any of the others.
Now he began his exhaustive study of bamboo. He learned that there
were more than twelve hundred known varieties of bamboo. He wanted to
find the most homogeneous variety. He sent out a number of men to hunt
this bamboo, and it is said that the search cost nearly $100,000. Six
thousand specimens of bamboo were carbonized, and he found three kinds
of bamboo and one of cane that gave almost the result he wanted. All
of these grew in a region near the Amazon, and were hard to get on
account of malarial conditions. But at last he discovered the bamboo
species that suited him, and he was ready to give his new light to the
world.
The world was waiting for it. Scientists and the press reported his
invention everywhere. He hung a row of lamps from the trees at Menlo
Park, and the thousands who came to see them wondered when they found
they could burn day and night for longer than a week. The lamps were
small and finely made, they could be lighted or extinguished by simply
pressing a button, and the cost of making them was slight. The last
doubters surrendered, and admitted that Edison had given the world a
new light, and one which was not simply a scientific marvel, but was
eminently practical and useful.
But Edison is never satisfied with what he has done in any line; he
must try to increase the service each invention gives. Therefore he
now conceived the idea of having a central station from which every
one might obtain electric light as they had formerly obtained gas.
There were gigantic difficulties in the way of such an undertaking.
Hardly any one outside of Edison’s own laboratory knew anything about
electric lighting, and there were only a few of them who could be
trusted to put a carbon filament in an exhausted globe.
He went about this new development in the most methodical way. He got
an insurance map of New York City, and studied the business section
from Wall to Canal Streets and from Broadway over to the East River.
He knew where every elevator shaft and boiler and fire-wall was, and
also how much gas each resident used and what he paid for it. This
last he learned by hiring men to walk through the district at two
o’clock in the afternoon and note how many gas lights were burning,
then to make the rounds again at three, and again at four, and so on
into the hours of the next morning.
With the field carefully examined he formed the New York Edison
Illuminating Company, and had his assistants take charge of factories
for making lamps, dynamos, sockets, and the other parts necessary for
his lights. It was very difficult to get the land he wanted for his
central station, but he finally bought two old buildings on Pearl
Street for $150,000. He had little room space and he wanted to get a
big output of electricity. So he decided to get a high-speed engine.
They were practically unknown then, and when he went to an engine
builder and said that he wanted a 150 horse-power engine that would
run 700 revolutions per minute he was told it was impossible. But he
found a man to build one for him, and set it up in the shop at Menlo
Park. The shop was built on a shale hill, and when the engine was
started the whole hill shook with the high speed revolutions. After
some experimenting and changing they got the power that Edison wanted,
and he ordered six more engines like the first.
In the meantime workmen had been busy digging ditches and laying mains
through the district that Edison intended to light. The engines were
set up in the central station and tried out. Then the troubles began.
The engines would not run evenly, one would stop and another go
dashing on at a tremendous speed. Edison tried a dozen different plans
before he brought anything like order out of that engine chaos.
Finally he had some engines built to run at 350 revolutions and give
175 horse-power, and these proved what was required. September 4,
1882, he turned the current on to the mains for the needed light
service, and it stayed on with only one short stoppage for eight
years.
In this way Edison invented the electric light and evolved the central
station that should provide the current wherever it was needed. At the
same time he had worked out countless adjuncts to it, the use of
the fine copper thread to serve as a fuse wire and prevent
short-circuiting, the meter, consisting of a small glass cell,
containing a solution in which two plates of zinc are placed, and
which shows how much current is supplied, the weighing voltameter, and
other instruments for estimating the current, and improvements on the
motors and engines. There was no field remotely connected with
electric lighting that he did not enter. Yet as soon as the invention
was actually before the world business competitors sprang up on
every hand. There was more litigation over this than over any other of
Edison’s inventions. “I fought for the lamp for fourteen years,” he
said, “and when I finally won my rights there were but three years of
the allotted seventeen left for my patent to live. Now it has become
the property of anybody and everybody.”
[Illustration: EDISON AND THE EARLY PHONOGRAPH]
Edison had always wanted a model laboratory, one that should be fitted
with the most perfect instruments obtainable, and supplied with all
the materials he could possibly require in any of his extraordinary
experiments. In 1886 he bought a house in Llewellyn Park, New Jersey,
and near the house ten acres of land, on which he built the laboratory
of his dreams. Here he had a large force of skilled workmen constantly
engaged in developing his ideas, and the expenses were paid by the
many commercial companies in which he was interested, and which
profited by the improvements he was continually making in their
machinery.
Many volumes might be written to tell of the “Wizard’s” achievements.
There has been no inventor who has covered such a field, and each step
he takes opens new and fascinating vistas to his ever-inquiring eyes.
Electricity is always his main study, and electricity he expects in
time will revolutionize modern life by making heat, power, and light
practically as cheap as air. But other subjects have concerned him
almost as much. He ranges from new processes for making guns to the
supplying of ready-made houses built of cement. Everything interests
him, every object tempts him to try his hand at improving on it.
The phonograph is his achievement, and the practical development of
the kinetoscope. He has built electric locomotives and run them, he
has made many discoveries in regard to platinum. His better known
patents include developments of the electric lamp, the telephone,
storage-batteries, ore-milling machinery, typewriters, electric pens,
vocal engines, addressing machines, cast-iron furniture, wire-drawing,
methods of preserving fruit, moving-picture machines, compressed-air
machines, and the manufacture of plate glass. He took out a patent
covering wireless telegraphy in 1891, but other matters were then
absorbing his attention, and he was quite willing to yield that field
to the brilliant Italian, Marconi. He feels no jealousy for other
inventors. He knows how vast the field is, and how many paths
constantly beckon him.
It is doubtless true that the great inventors are born and not made,
but many of them seem, nevertheless, to have drifted into the work
that gave them fame, or to have hit by chance on their compelling
idea. It was not so with Edison. He was beyond any doubt born an
inventor. With him to see was to ask the question why, and to ask that
question was to start his thoughts on the train that was to bring him
to the answer.
XV
MARCONI AND THE WIRELESS TELEGRAPH
1874-
At first sight the wireless telegraph seems the most wonderful of all
inventions and discoveries, the one that is least easy to understand,
and that most nearly approaches that magic which is above all nature’s
laws. Even if we do come to understand it it loses nothing of its
wonder, and the last impression is very like the first. We can
understand how an electric current travels through a wire, even if we
cannot understand electricity, but how that current can travel through
limitless space and yet reach its destination strains the imagination.
Yet wireless telegraphy is not a matter of the imagination, but of
exact, demonstrable science.
On December 12, 1901, a quiet, dark-skinned young man sat, about
noontime, in a room of the old barracks building on Signal Hill, near
St. John’s, Newfoundland. On the table in front of him was a
mechanical apparatus, with an ordinary telephone receiver at its side.
The window was partly open, and a wire led from the machine on the
table through the window to a gigantic kite that a high wind kept
flying fully 400 feet above the room. The young man picked up the
receiver, and held it to his ear for a long time. His face showed no
sign of excitement, though an assistant, standing near him, could
barely keep still. Then, suddenly, came the sharp click of the
“tapper” as it struck the “coherer.” That meant that something was
coming. The young man listened a few minutes, and then handed the
receiver to his assistant. “See if you can hear anything, Mr. Kemp,”
said he. The other man took the receiver, and a moment later his ear
caught the sound of three little clicks, faint, but distinct and
unmistakable, the three dots of the letter S in the Morse Code. Those
clicks had been sent from Poldhu, on the Cornish coast of England, and
they had traveled through air across the Atlantic Ocean without any
wire to guide them. That was one of the great moments of history. The
young man at the table was Guglielmo Marconi, an Italian.
We know that it is no injustice to a great inventor to say that other
men had imagined what he achieved, and had earlier tried to prove
their theories. It takes nothing from the glory of that other great
Italian, Columbus, to recall that other sailors had planned to cross
the sea to the west of Europe and that some had tried it. So James
Clerk-Maxwell had proved by mathematics the electro-magnetic theory of
light in 1864, and Heinrich Hertz had demonstrated in 1888 by actual
experiment that electric waves exist in the free ether, and Edison had
for a time worked on the problem of a wireless telegraph. Marconi
devised the last link that made the wonder possible, and caught the
first click that came across the sea, and to him belong the palms.
Judge Townsend, in deciding a suit in a United States court in 1905,
declared, “It would seem, therefore, to be a sufficient answer to the
attempts to belittle Marconi’s great invention that, with the whole
scientific world awakened by the disclosures of Hertz in 1887 to the
new and undeveloped possibilities of electric waves, nine years
elapsed without a single practical or commercially successful result,
and Marconi was the first to describe and the first to achieve the
transmission of definite intelligible signals by means of these
Hertzian waves.”
Marconi was born at Villa Griffone, near Bologna, in 1874, so that he
was under thirty when he caught that first transatlantic message. He
studied at Leghorn under Professor Rosa, and later at the University
of Bologna with Professor Righi. He was always absorbed in science,
and experimented, holiday after holiday, on his father’s estate. He
was precocious to an extraordinary degree, for in 1895, when only
twenty-one, he had produced a wireless transmitting apparatus that he
patented in Italy. Within a year he had taken out patents in England
and in other European countries, and had proposed a wireless telegraph
system to the English Post-Office Department. That Department, through
Sir William Henry Preece, Engineer-in-Chief of Telegraphs, took up the
subject, and reported very favorably on the Marconi System. Marconi
himself, at the House of Commons, telegraphed by wireless across the
Thames, a distance of 250 yards. In June, 1897, he sent a message nine
miles, in July twelve miles, and in 1898 he succeeded in sending one
across the English Channel to France, thirty-two miles. In 1901 he
covered a space of 3,000 miles.
Let us now see what it was that Marconi had actually done.