May 16, 1948, pp. 1147 - 1159
Accomplishments of Nikola Tesla
by Kenneth M. Swezey
In the early 1890s, Tesla discovered the "rotating magnetic field. produced
by two or more alternating currents out of step with each other.
Based on this discovery, Tesla proceeded to invent the prototypes of almost all practical alternating current motors and the whole polyphase system for generating, transmitting, and distributing electric current as well.
The first Tesla polyphase system patents were granted on May 1, 1888. The Westinghouse Electric Company acquired rights to them several months later, and in 1893 was able to demonstrate a complete system at the Chicago World's Fair. The demonstration was so convincing that - against the warnings of such men as Edison and Lord Kelvin - the Tesla system was adopted for the first great hydro-electric plant at Niagara Falls, which started operation in 1895. A year later, Niagara power was running street cars and lights in Buffalo. The age of Electric Power was thus born.
Today, practically all electricity in the world is generated, transmitted, and
turned into mechanical power by means of the Tesla Polyphase System. Without
this system, the giant steam-electric power plants in our big cities and the big
hydroelectric protects such as TVA, Boulder Dam, Grand Coulee, would be
Although practically unknown to the layman, the Tesla polyphase inventions are, without question, the most important single group of inventions in the whole field of electrical engineering.
Dr. L. W. Austin, head of the radio section of the Bureau of Standards for many
years, Prof, Slaby, German radio pioneer (the "Marconi of Germany"),
M. E. Girardeau, French radio authority, and others, have called Tesla the
"Father of the Wireless." This was for his inventions and discoveries
made at least several years before the very first experiments of Marconi and
others. Here are several:
- High frequency generators for producing continuous waves.
- Coupled and tuned circuits.
- Rotary and series spark gaps.
- Oil-insulated transformers and condensers.
- Mica condensers impregnated with wax under vacuum.
- Stranded conductors.
- Aerial and ground connection.
- Selective tuning by beat waves or heterodyning.
- Arcs for producing continuous waves.
- "Ticker" for receiving continuous waves.
- Choke coils.
- Radio-Controlled Vessels.
Before 1897, Tesla devised boats, cars, and other movable objects that could be
maneuvered completely by radio waves. He demonstrated these widely in New York
in 1898, and before the Commercial Club in Chicago in 1899. This work with what
Tesla called "Telautomatics," advanced later by John Hays Hammond, Jr.
and others, was the beginning of the concept which has led to today's guided
High Frequency Induction Furnace and Heating
In the early 1890's, Tesla described heating bars of iron and melting lead and
tin in the field of specially designed high-frequency coils, also of heating
dielectrics in such fields. When, in 1916, Dr. Edwin Northrup devised his first
commercial high-frequency furnace, he told me he had gone back for his
inspiration to the old ideas and circuits of Tesla.
During this same period, Tesla developed apparatus for producing high voltage,
high frequency "Tesla currents." He first reasoned, then demonstrated
on himself that very high voltages could be taken safely into the human body
provided the frequencies were high enough - thus making a discovery in
physiology. Soon after, adapted by D'Arsonval and others, the Tesla apparatus
became the basic tool of diathermy and other forms of high-frequency
Neon and Fluorescent Lighting
Before 1893, Tesla devised all kinds of wirelessly-lit vacuum and gas-filled tubes. He increased the brilliance of some by using uranium glass or coating them with phosphors - thus creating pioneer fluorescent tubes. He bent many to suit the requirements of the room they were to light, and others to form words or names just as we do in modern display lighting. Tesla displayed some of his neon-type tubes in his personal exhibit at the 1893 World's Fair.
Tesla devised a turbine having smooth parallel blades, without buckets. The principle, which involved the friction of air, steam, or gas, at high velocity, was used to couple the elements of a speedometer made for years by Waltham and used on many of our best cars.
At his Colorado Springs laboratory in 1899 and 1900, Tesla produced artificial lightning crashes of many millions of volts and up to 135 feet long - a feat never since equalled.
Synchronous Electric Clocks
In his talk before the International Electrical Congress, August 25, 1893, at the Chicago Fair, he demonstrated several synchronous electric clocks. In a statement regarding his "World System. of wireless power, made in 1900, he mentioned cheap synchronous clocks all over the world which would be powered and kept in step by a single master generator in the United States. No one put such clocks into commercial use until about 1916.
Though more in the form of prophecy (as there was no equipment at the time capable of carrying it out), Tesla wrote in 1917 of ideas he claims he had many years before in which vessels and other distant objects could be detected by training on them an extremely powerful ray of short-wave electrical impulses and picking up a reflection on a fluorescent screen. Marconi was hailed as the progenitor of this idea when he made a similar, but less detailed, prophecy in 1922 - at a time when there was still no means to effectively carry it out.
As another promise for his "World Wireless,. of 1900, Tesla proposed: "The interconnection and operation of all the telephone exchanges on the globe; the world transmission of typed or hand-written characters, letters, checks, etc.; the in- auguration of a system of world printing; the world reproduction of photographs and all kinds of drawings or records." Prof. Arthur Korn, who actually sent the first pictures by wireless, credits Tesla with some of his system.
At the turn of the century, Tesla also said this of his system: "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,
where it will record the world's news or such special messages as may be
intended for it."
In an article of appreciation of Tesla's work, published in the Scientific Monthly, just after Tesla died in 1943, Major E. H. Armstrong quoted the statement above and commented: "Of course the instrumentalities for practicing broadcasting were not then in existence. Tesla was classed as a visionary and his prophecy was forgotten. What harsher terms might, with justice, be applied to many of us who helped produce the instrumentalities with which broadcasting was eventually accomplished' We applied them to point-to-point communication, failing completely to realize the significance of Tesla's words."