|
|
Home
| Tesla
Writings | Tesla Patents
| Tesla FAQ | Tesla
On AC |
Tesla
Books | Glossary
| Links Bookstore | Newsletter | Wholesale Book List | Contact Us | Reference Section | Search | Site Map |
|
THE TRANSMISSION OF ELECTRICAL ENERGY WITHOUT WIRESby Nikola Tesla |
Electrical World and Engineer, March 5, 1904 It is impossible to resist your courteous request extended on an
occasion of such moment in the life of your journal. Your letter has
vivified the memory of our beginning friendship, of the first imperfect
attempts and undeserved successes, of kindnesses and misunderstandings.
It has brought painfully to my mind the greatness of early expectations,
the quick flight of time, and alas! the smallness of realizations. The
following lines which, but for your initiative, might not have been
given to the world for a long time yet, are an offering in the friendly
spirit of old, and my best wishes for your future success accompany
them.
Towards the close of 1898 a systematic research, carried on for a
number of years with the object of perfecting a method of transmission
of electrical energy through the natural medium, led me to recognize
three important necessities: First, to develop a transmitter of great
power; second, to perfect means for individualizing and isolating the
energy transmitted; and, third, to ascertain the laws of propagation of
currents through the earth and the atmosphere. Various reasons, not the
least of which was the help proffered by my friend Leonard E. Curtis and
the Colorado Springs Electric Company, determined me to select for my
experimental investigations the large plateau, two thousand meters above
sea-level, in the vicinity of that delightful resort, which I reached
late in May, 1899. I had not been there but a few days when I
congratulated myself on the happy choice and I began the task, for which
I had long trained myself, with a grateful sense and full of inspiring
hope. The perfect purity of the air, the unequaled beauty of the sky,
the imposing sight of a high mountain range, the quiet and restfulness
of the place—all around contributed to make the conditions for
scientific observations ideal. To this was added the exhilarating
influence of a glorious climate and a singular sharpening of the senses.
In those regions the organs undergo perceptible physical changes. The
eyes assume an extraordinary limpidity, improving vision; the ears dry
out and become more susceptible to sound. Objects can be clearly
distinguished there at distances such that I prefer to have them told by
someone else, and I have heard—this I can venture to vouch for—the
claps of thunder seven and eight hundred kilometers away. I might have
done better still, had it not been tedious to wait for the sounds to
arrive, in definite intervals, as heralded precisely by an electrical
indicating apparatus—nearly an hour before.
In the middle of June, while preparations for other work were going
on, I arranged one of my receiving transformers with the view of
determining in a novel manner, experimentally, the electric potential of
the globe and studying its periodic and casual fluctuations. This formed
part of a plan carefully mapped out in advance. A highly sensitive,
self-restorative device, controlling a recording instrument, was
included in the secondary circuit, while the primary was connected to
the ground and an elevated terminal of adjustable capacity. The
variations of potential gave rise to electric surgings in the primary;
these generated secondary currents, which in turn affected the sensitive
device and recorder in proportion to their intensity. The earth was
found to be, literally, alive with electrical vibrations, and soon I was
deeply absorbed in the interesting investigation. No better
opportunities for such observations as I intended to make could be found
anywhere. Colorado is a country famous for the natural displays of
electric force. In that dry and rarefied atmosphere the sun's rays beat
the objects with fierce intensity. I raised steam, to a dangerous
pressure, in barrels filled with concentrated salt solution, and the
tin-foil coatings of some of my elevated terminals shriveled up in the
fiery blaze. An experimental high-tension transformer, carelessly
exposed to the rays of the setting sun, had most of its insulating
compound melted out and was rendered useless. Aided by the dryness and
rarefaction of the air, the water evaporates as in a boiler, and static
electricity is developed in abundance. Lightning discharges are,
accordingly, very frequent and sometimes of inconceivable violence. On
one occasion approximately twelve thousand discharges occurred in two
hours, and all in a radius of certainly less than fifty kilometers from
the laboratory. Many of them resembled gigantic trees of fire with the
trunks up or down. I never saw fire balls, but as compensation for my
disappointment I succeeded later in determining the mode of their
formation and producing them artificially.
In the latter part of the same month I noticed several times that my
instruments were affected stronger by discharges taking place at great
distances than by those near by. This puzzled me very much. What was the
cause? A number of observations proved that it could not be due to the
differences in the intensity of the individual discharges, and I readily
ascertained that the phenomenon was not the result of a varying relation
between the periods of my receiving circuits and those of the
terrestrial disturbances. One night, as I was walking home with an
assistant, meditating over these experiences, I was suddenly staggered
by a thought. Years ago, when I wrote a chapter of my lecture before the
Franklin Institute and the National Electric Light Association, it had
presented itself to me, but I dismissed it as absurd and impossible. I
banished it again. Nevertheless, my instinct was aroused and somehow I
felt that I was nearing a great revelation.
It was on the third of July—the date I shall never forget—when I
obtained the first decisive experimental evidence of a truth of
overwhelming importance for the advancement of humanity. A dense mass of
strongly charged clouds gathered in the west and towards the evening a
violent storm broke loose which, after spending much of its fury in the
mountains, was driven away with great velocity over the plains. Heavy
and long persisting arcs formed almost in regular time intervals. My
observations were now greatly facilitated and rendered more accurate by
the experiences already gained. I was able to handle my instruments
quickly and I was prepared. The recording apparatus being properly
adjusted, its indications became fainter and fainter with the increasing
distance of the storm, until they ceased altogether. I was watching in
eager expectation. Surely enough, in a little while the indications
again began, grew stronger and stronger and, after passing through a
maximum, gradually decreased and ceased once more. Many times, in
regularly recurring intervals, the same actions were repeated until the
storm which, as evident from simple computations, was moving with nearly
constant speed, had retreated to a distance of about three hundred
kilometers. Nor did these strange actions stop then, but continued to
manifest themselves with undiminished force. Subsequently, similar
observations were also made by my assistant, Mr. Fritz Lowenstein, and
shortly afterward several admirable opportunities presented themselves
which brought out, still more forcibly, and unmistakably, the true
nature of the wonderful phenomenon. No doubt, whatever remained: I was
observing stationary waves.
As the source of disturbances moved away the receiving circuit came
successively upon their nodes and loops. Impossible as it seemed, this
planet, despite its vast extent, behaved like a conductor of limited
dimensions. The tremendous significance of this fact in the transmission
of energy by my system had already become quite clear to me. Not only
was it practicable to send telegraphic messages to any distance without
wires, as I recognized long ago, but also to impress upon the entire
globe the faint modulations of the human voice, far more still, to
transmit power, in unlimited amounts, to any terrestrial distance and
almost without loss.
With these stupendous possibilities in sight, and the experimental
evidence before me that their realization was henceforth merely a
question of expert knowledge, patience and skill, I attacked vigorously
the development of my magnifying transmitter, now, however, not so much
with the original intention of producing one of great power, as with the
object of learning how to construct the best one. This is, essentially,
a circuit of very high self-induction and small resistance which in its
arrangement, mode of excitation and action, may be said to be the
diametrical opposite of a transmitting circuit typical of telegraphy by
Hertzian or electromagnetic radiations. It is difficult to form an
adequate idea of the marvelous power of this unique appliance, by the
aid of which the globe will be transformed. The electromagnetic
radiations being reduced to an insignificant quantity, and proper
conditions of resonance maintained, the circuit acts like an immense
pendulum, storing indefinitely the energy of the primary exciting
impulses and impressions upon the earth of the primary exciting impulses
and impressions upon the earth and its conducting atmosphere uniform
harmonic oscillations of intensities which, as actual tests have shown,
may be pushed so far as to surpass those attained in the natural
displays of static electricity.
Simultaneously with these endeavors, the means of individualization
and isolation were gradually improved. Great importance was attached to
this, for it was found that simple tuning was not sufficient to meet the
vigorous practical requirements. The fundamental idea of employing a
number of distinctive elements, co-operatively associated, for the
purpose of isolating energy transmitted, I trace directly to my perusal
of Spencer's clear and suggestive exposition of the human nerve
mechanism. The influence of this principle on the transmission of
intelligence, and electrical energy in general, cannot as yet be
estimated, for the art is still in the embryonic stage; but many
thousands of simultaneous telegraphic and telephonic messages, through
one single conducting channel, natural or artificial, and without
serious mutual interference, are certainly practicable, while millions
are possible. On the other hand, any desired degree of individualization
may be secured by the use of a great number of co-operative elements and
arbitrary variation of their distinctive features and order of
succession. For obvious reasons, the principle will also be valuable in
the extension of the distance of transmission.
Progress though of necessity slow was steady and sure, for the
objects aimed at were in a direction of my constant study and exercise.
It is, therefore, not astonishing that before the end of 1899 I
completed the task undertaken and reached the results which I have
announced in my article in the Century Magazine of June, 1900, every
word of which was carefully weighed.
Much has already been done towards making my system commercially
available, in the transmission of energy in small amounts for specific
purposes, as well as on an industrial scale. The results attained by me
have made my scheme of intelligence transmission, for which the name of
"World Telegraphy" has been suggested, easily realizable. It
constitutes, I believe, in its principle of operation, means employed
and capacities of application, a radical and fruitful departure from
what has been done heretofore. I have no doubt that it will prove very
efficient in enlightening the masses, particularly in still uncivilized
countries and less accessible regions, and that it will add materially
to general safety, comfort and convenience, and maintenance of peaceful
relations. It involves the employment of a number of plants, all of
which are capable of transmitting individualized signals to the
uttermost confines of the earth. Each of them will be preferably located
near some important center of civilization and the news it receives
through any channel will be flashed to all points of the globe. A cheap
and simple device, which might be carried in one's pocket, may then be
set up somewhere on sea or land, and it will record the world's news or
such special messages as may be intended for it. Thus the entire earth
will be converted into a huge brain, as it were, capable of response in
every one of its parts. Since a single plant of but one hundred
horse-power can operate hundreds of millions of instruments, the system
will have a virtually infinite working capacity, and it must needs
immensely facilitate and cheapen the transmission of intelligence.
The first of these central plants would have been already completed
had it not been for unforeseen delays which, fortunately, have nothing
to do with its purely technical features. But this loss of time, while
vexatious, may, after all, prove to be a blessing in disguise. The best
design of which I know has been adopted, and the transmitter will emit a
wave complex of total maximum activity of ten million horse-power, one
per cent. of which is amply sufficient to "girdle the globe."
This enormous rate of energy delivery, approximately twice that of the
combined falls of Niagara, is obtainable only by the use of certain
artifices, which I shall make known in due course.
For a large part of the work which I have done so far I am indebted
to the noble generosity of Mr. J. Pierpont Morgan, which was all the
more welcome and stimulating, as it was extended at a time when those,
who have since promised most, were the greatest of doubters. I have also
to thank my friend, Stanford White, for much unselfish and valuable
assistance. This work is now far advanced, and though the results may be
tardy, they are sure to come.
Meanwhile, the transmission of energy on an industrial scale is not
being neglected. The Canadian Niagara Power Company have offered me a
splendid inducement, and next to achieving success for the sake of the
art, it will give me the greatest satisfaction to make their concession
financially profitable to them. In this first power plant, which I have
been designing for a long time, I propose to distribute ten thousand
horse-power under a tension of one hundred million volts, which I am now
able to produce and handle with safety.
This energy will be collected all over the globe preferably in small
amounts, ranging from a fraction of one to a few horse-power. One its
chief uses will be the illumination of isolated homes. It takes very
little power to light a dwelling with vacuum tubes operated by
high-frequency currents and in each instance a terminal a little above
the roof will be sufficient. Another valuable application will be the
driving of clocks and other such apparatus. These clocks will be
exceedingly simple, will require absolutely no attention and will
indicate rigorously correct time. The idea of impressing upon the earth
American time is fascinating and very likely to become popular. There
are innumerable devices of all kinds which are either now employed or
can be supplied, and by operating them in this manner I may be able to
offer a great convenience to whole world with a plant of no more than
ten thousand horse-power. The introduction of this system will give
opportunities for invention and manufacture such as have never presented
themselves before.
Knowing the far-reaching importance of this first attempt and its
effect upon future development, I shall proceed slowly and carefully.
Experience has taught me not to assign a term to enterprises the
consummation of which is not wholly dependent on my own abilities and
exertions. But I am hopeful that these great realizations are not far
off, and I know that when this first work is completed they will follow
with mathematical certitude.
When the great truth accidentally revealed and experimentally
confirmed is fully recognized, that this planet, with all its appalling
immensity, is to electric currents virtually no more than a small metal
ball and that by this fact many possibilities, each baffling imagination
and of incalculable consequence, are rendered absolutely sure of
accomplishment; when the first plant is inaugurated and it is shown that
a telegraphic message, almost as secret and non-interferable as a
thought, can be transmitted to any terrestrial distance, the sound of
the human voice, with all its intonations and inflections, faithfully
and instantly reproduced at any other point of the globe, the energy of
a waterfall made available for supplying light, heat or motive power,
anywhere-on sea, or land, or high in the air-humanity will be like an
ant heap stirred up with a stick: See the excitement coming! |
||
Home
| Tesla
Writings | Tesla Patents
| Tesla FAQ | Tesla
On AC |
Tesla
Books | Glossary
| Links |
|
21st Century
Books © 1998-2013 Twenty-First
Century Books, Colorado
|