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 agree that it was
Guglielmo Marconi, but this author makes
a case for none other than Thomas Edison. I don't recall ever hear anyone making that
claim before, but 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
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
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 electric force.
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
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 July 19, 2019