October 1970 Popular Electronics
Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
Just as you will never get everyone
to agree on who was the first person to successfully fly a powered aircraft (Wright,
Whitehead, Curtiss, etc.), there will never be a consensus on who invented the radio.
Most people would probably say it was Marconi, but this author makes a case for none
other than Thomas Edison. Before you dismiss the opinion, read on...
A Question of Semantics
Who Did Invent Radio?
By Fred Shunaman
In all probability there will never be total agreement on the question of who actually
discovered radio. In fact, the word "radio" itself does not stand up to a strict historical
interpretation. Does the "first radio" mean the first two-way wireless communication?
Or a one-way wireless transmission? Or would a minor laboratory demonstration and a patent
establish the precedency of the discoverer/inventor?
In one way or another, Marconi, Popov, Loomis, Butterfield, Lodge, Hertz and Tesla
all qualify as discoverers of radio. However, history now shows that none of these men
has the supporting evidence of discovery that belongs to Thomas Alva Edison-to whom the
honor may rightfully belong.
A simple language difficulty may have cost Edison the credit for first discovering
and using radio as a means of communication. He announced the discovery of "etheric force"
when Marconi was only a year old and while Tesla was still attending school. And, in
1885, two years before Hertz announced the discovery of electromagnetic waves, Edison
applied for a patent on a complete wireless system. Submitted with his application were
patent drawings of radio towers and antennas on the masts of ships.
How It All Began. During the evening of November 22, 1875, Edison was studying the
action of a magnetic vibrator. He noticed a tiny spark between the armature and core
of the vibrator as the armature approached the core. Suspecting faulty insulation, he
checked the coil but found everything in order.
Above is one of the drawings from Edison's Patent No. 465,971, Dec.
29, 1891, describing a "Means for Transmitting Signals Electrically." Particularly interested
in transmitting across bodies of water, he showed high towers and ships carrying "condensing
surfaces" (which we would call antennas). At the right is an enlargement of the insert,
in which Edison described how signal was generated and transmitted to antenna.
Edison's "black box" 1881 demonstration had graphite points which
could be connected to an external circuit. The extension eye-shade permitted viewer to
see, jumping between the contacts, sparks unlike any known to an electrical phenomenon
at that period.
Thomas A. Edison, from a print dated 1877, about the time he was working
on his "etheric force" invention. This and other illustrations in this article are adapted
from those appearing in "Menlo Park Reminiscences," Vol. I, by F. Jehl, Edison Institute,
Dearborn Park, Mich.
However, Edison reported that; "If we touched any part of the vibrator we got the
spark," and that "the larger the body of iron touched to the vibrator, the larger the
spark." If a wire was connected between the vibrator and a gas jet on the wall, a spark
could be drawn from the gas pipes anywhere in the room.
Then Edison performed the experiment that Hertz was to do 17 years later; he found
that "if you turn the wire round on itself and let the point of the wire touch any part
of itself, you get a spark .... This is simply wonderful and a good proof that the cause
of the spark is not now known force."
Next, Edison constructed a demonstration apparatus and revealed his new etheric force"
to the Polyclinic Club of the American Institute. Many of the members seemed upset by
the name he had chosen for the new effect. But Edison was undaunted, and he predicted
(in the January 1876 issue of the Operator, a telegrapher's magazine) that the new force
might become the telegraphic medium of the future. He is quoted as having stated: "The
cumbersome appliances of transmitting ordinary electricity, such as telegraph poles,
insulating knobs, cable sheathings, and so on, may be left out of the problem of quick
and easy telegraphic transmission, and a great saving of time and labor accomplished."
The Scientific American of December 1875 stated: "By this simple means signals have
been sent [by wire] for long distances, as from Mr. Edison's laboratory to his dwelling
house in another part of the town. Mr. Edison states that signals have also been sent
the distance of 75 miles on an open circuit, by attaching a conducting wire to the "Western
Union telegraph line."
As It Developed. A "black box," used by Edison to demonstrate etheric force was sent
to Paris where Edison's assistant, Charles Batchelor, lectured on the etheric force.
(The black box detector consisted of a pair of adjustable graphite points in a shaded
enclosure, with terminals to attach it to an external circuit.) There is a bare possibility
that Heinrich Hertz might have heard about Edison's experiments, for hi spark points
with the micrometer adjustment are virtually identical to those in the black box, and
he repeated the experiment of turning the wire back upon itself.
Work on the telephone took Edison's attention away from etheric force for some time.
But in 1885 he applied for a patent for a wireless telegraph system based on his etheric
force. The patent drawings show towers that are easily recognizable as radio masts, and
two ships with broad ribbon-like antennas hung between their masts! The text of the patent
application goes into detail about the equipment shown in the drawings.
"The wire (from the 'condensing surface' C) extends through an electromotograph telephone
receiver D (Fig. 2) or other suitable receiver, and also includes the secondary circuit
of an induction coil F. In the primary of this coil is a battery b and a revolving circuit-breaker
G. This circuit-breaker ... is short-circuited normally by a backpoint key K, by depressing
which ... the circuit-breaker makes and breaks the primary circuit of the induction coil
with great rapidity," Edison wrote.
Explaining the phenomenon as he saw it, Edison went on to state: "These electric impulses
are transmitted inductively to the elevated condensing surface at the distant point ...
Here is where the confusion in language occurred. At the time, the term induction,
unless otherwise explained, meant electrostatic induction (a tendency that still lingers
on in some elementary physics textbooks). The transformer had just been invented, and
magnetic induction was a laboratory curiosity. The term "electrostatic" drifted into
obscurity as the art progressed, and later writers referring to the "induction telegraph"
unquestioningly accepted the term to mean magnetic induction.
The confusion was increased because the only commercial use Edison made of his invention
was the "grasshopper telegraph," a system of telegraphing from moving trains to the telegraph
wires alongside the tracks. This was a distance that could be covered easily by electromagnetic
induction, and historians who believe that radio communication started with Tesla, Lodge,
and Marconi assumed that this was the case. Yet, in explaining the "grasshopper telegraph"
to a reporter, Edison said, "The system works by electrostatic induction."
So, a change in the generally accepted meaning of a word with the changing times buried
the fact that Edison invented, described, patented, and operated a radiotelegraph system
in 1886 - a year before Hertz explained the cause of the etheric force, which he called
What other "firsts" .may lay buried or attributed to other discoverers because semantics
denied the original inventor or discoverer his due? At least now Thomas Alva Edison's
long list of achievements will have numbered among them the discovery of radio waves
- even if he did not title them as such.
Editor's Note: We are given to understand that the graphic-points "black box" is still
in existence and has been exhibited on the second floor of the restored Edison Laboratory.
In his book, "Menlo Park Reminiscences" (now believed to be out of print and unobtainable),
author Jehl says that Edison was intrigued by the spark and performed many experiments
to seek an explanation of its nature. Edison did find that the spark was unpolarized;
had no respect for the usual types of insulation; would not discharge a Leyden jar; and
had no effect on his electroscopes.
Unquestionably, Edison had stumbled onto radio-wave transmission, but the fact that
energy could be propagated through the atmosphere and not via wires was alien to all
of his telegraphy experiments.
Posted September 15, 2011