Although experimenter Nathan Stubblefield worked in the "wireless" communication field, it appears that he employed short range conduction and induction, and not electromagnetic radio signals.
 
Saint Louis Post-Dispatch, January 12, 1902, Sunday Magazine, page 3:

KENTUCKY  FARMER  INVENTS  WIRELESS  TELEPHONE

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Nathan  Stubblefield  Raises  Vegetables  for  Market  in  Order  That  He  May  Live,  But  Has  for  Ten  Years  Devoted  All  of  His  Spare  Time  to  Electrical  Experiments,  Until  Now  He  Has  Perfected  a  Wireless  Telephone  System  Over  Which  Messages  Are  Distinctly  Heard  at  a  Mile.

NATHAN STUBBLEFIELD, a Kentucky truck farmer, claims to have discovered telephoning without wires. At a public exhibition in Murray, Calloway County, Ky., on Jan. 1, he convinced a thousand people of the truth of his claim.
    The principle on which he works he will not reveal, and guards his secret jealously.
    In telephoning without wires, Stubblefield uses the ordinary telephone transmitter and receiver, connected with the earth by insulated wires. The apparatus by means of which vibrations of the electric current is produced is concealed in a box about four feet high, two and one-half feet wide, and one and one-half feet deep. No one but Mr. Stubblefield and his 14-year-old son, Bernard, knows the contents of this box.
    At the public test of wireless telephony held in Murray, Ky., Mr. Stubblefield placed his transmitter in the courthouse square, and ran two wires from it into the ground. He established five "listening" stations in various parts of the town, the furthest six blocks distant from the transmitter. Then Mr. Stubblefield's son took his place at the transmitter and talked in a tone of voice such as is ordinarily used in telephoning. He talked, whispered, whistled and played a harmonica. Simultaneously everyone at the receivers heard him with remarkable distinctness. And at that moment Mr. Stubblefield became a prophet with honor in his own country.
 
By a Staff Correspondent of the Sunday Post-Dispatch.MURRAY, Ky., Jan. 10.          
HOWEVER undeveloped his system may be, Nathan Stubblefield, the farmer-inventor of Kentucky, has assuredly discovered the principle of telephoning without wires, using only the earth's electrical charge for the transmission of the voice from one distant point to another.
    Today he gave the Sunday Post-Dispatch a practical demonstration of his ability to do this and discussed his discovery as frankly as his own interest and self-protection would permit.
    I drove to Mr. Stubblefield's farm, about two miles from Murray, and was received with the usual hospitality of Kentucky.
    Previously Mr. Stubblefield had never permitted a newspaper correspondent to approach his house nearer than the road that runs before it, so jealously has he guarded the workshop in which his experiments were made. He has worked for ten years to discover an apparatus by which he could overcome the use of wires in telephoning, during which time he has become a technical electrician of high order. He has kept in touch with all the leading electricians, and is familiar with every important discovery in the field of electricity. Naturally he has been a close observer of the work of Marconi. Nathan Stubblefield and Bernard Stubblefield and wireless telephone equipment
    "Before speaking of my discovery," said Mr. Stubblefield, "I desire to show you my apparatus and give you convincing proof of its ability to perform what I claim for it, the transmission of the voice without wires."
    He led the way to a tiny workshop built onto the porch on the front of his house. It was just wide enough to hold the transmitter, which stood before the window, and a chair. One end of the room was given up to shelves laden with technical books on electricity.
    The transmitting apparatus is concealed in a box before described. Two wires of the thickness of a lead pencil coil from its corners and disappear through the walls of the room, and enter the ground outside. On top of the box is an ordinary telephone transmitter and a telephone switch. This is the machine through which the voice of the sender is passed into the ground, to be transmitted by the earth's electrical waves to the ear of the person who has an instrument capable of receiving and reproducing it.
    The son of Mr. Stubblefield was left at the house to send the messages.
    We went into the cornfield back of the house. Five hundred yards away we came to the experimental station the inventor has used for several months in working out his wireless telephony theory. It is a dry goods box fastened to the top of a stump. A roof to shed the rain has been placed on top of it; one side is hinged for a door, and the wires connected with the ground on both sides run into it and are attached to a pair of telephone receivers. The box was built as a shelter from the weather, and as a protection to the receivers. I took a seat in the box and Mr. Stubblefield shouted a "hello" to the house. This was a signal to his son to begin sending messages.
    I placed the receiver to my ears and listened. Presently there came with extraordinary distinctness several spasmodic buzzings and then a voice which said:
    "Hello, can you hear me? Now I will count ten. One--two--three--four--five--six--seven--eight--nine--ten. Did you hear that? Now I will whisper."
    I heard as clearly as if the speaker were only across a 12-foot room the ten numerals whispered.
    "Now I will whistle," said the voice.
    For a minute or more the tuneless whistle of a boy was conveyed to the listener's ears.
    "I am going to play the mouth organ now," said the voice.
    Immediately came the strains of a harmonica played without melody, but the notes were clear and unmistakable.
    "I will now repeat the program," said the voice, and it did.
    Meanwhile Mr. Stubblefield paced back and forth some distance from the station, calling occasionally, "Is he talking to you?" to which I nodded reply.
    An examination of the station showed that the wires leading from the receivers terminated in steel rods, each of which was tapped with a hollow nickel-plated ball of iron, below which was an inverted metal cup. The wire enters the ball at the top and is attached to the rod. The rod is thrust into the ground two-thirds of its length. Another test was made after the rods had been drawn from the ground and thrust into it again at a spot chosen haphazard by the correspondent. Again the "hello" signal was made by Stubblefield, and after a few minutes wait came, the mysterious "Hello! Can you hear me?" and a repetition of the program of counted numerals, whispers, whistling and harmonica playing.
    "Now," said Mr. Stubblefield, who carried under his arm duplicates of the ball-tipped steel-rods. "I wish you would lead the way. Go where you will, sink the rods into the ground and listen for a telephone message."
    Away we went, down a wagon track, through the wide cornfield. A gate was opened into a lane between the hedge that bordered the field and a dense oak woods. We pursued the lane for about 500 yards and struck into the woods. I led the way. Into the heart of the woods we walked for nearly a mile.
    In a ravine I stopped.
    "How far are we from the house now?" I asked.
    "About a mile," Stubblefield answered. "Place the rods where you will and listen for a telephone message."
    I took the four rods from Stubblefield. Each pair of rods was joined by an ordinary insulated wire about 30 feet long, in the center of which was a small round telephone receiver.
    Two by two the rods were sunk in the ground, about half their length, the wires between them hanging loosely, and with plenty of play. I placed a receiver at each ear and waited. In a few moments came the signaling "buzz" and the voice of Stubblefield's son saying, "Hello! Can you hear me? Now I will count ten, etc." He went through the program heard at the station in the cornfield. The voice was quite as clear and distinct as it was 500 yards from the transmitting station.
    Stubblefield leaned against a tree, saying nothing, his arms folded, but with a look of triumph on his face. The deep silence of the woods made the mysterious voice with its message from a mile or more away, received by no visible means, seem eerie. Perhaps a look on my face prompted Stubblefield to say:
    "It makes me feel queer myself when I hear that voice come out of the ground, as often I have heard it in our experiments."
    The rods were moved here and there but always the message came. At intervals for an hour or more the boy at the house repeated over and over again the message into the transmitter in obedience to his father's request and the demands of the test.
    On the way back to the house through the wood and field Stubblefield told of his discovery. He bears the stamp of genius. He is a recluse. He has the thoughtful, absent air. He is eccentric. His neighbors shun him, while they respect him. None ever intrudes upon his privacy--they know well that such intrusion means a rebuff long to be remembered. The little town of Murray is full of stories of his eccentricities, which, possibly, are the growth of not understanding a man whose ideals were far beyond those of the neighborhood. Where once they laughed at him and called him a crank, now they look up to him with awe. He has done something.
Nathan Stubblefield receiving telephone signals
    Stubblefield is 40, slender and of the well-to-do farmer type, but far above it mentally. For a livelihood he grows fruit--and the best in his section. His melons are said to be dreams of deliciousness. He protects his patch with electric wires, which announce to him the presence of intruders. Like other Kentuckians he knows how to use a shotgun. His melon patch and his orchard are, therefore, not often molested.
    He comes from a family distinguished in his locality. His father was a lawyer, much respected in that part of Kentucky, and passing rich. His brothers are merchants, "well off," as the saying is, and leaders in the community. But Nathan Stubblefield is a man aloof. He cares only for his home, his family, and--electricity. He educates his children in person, and after seeing that his family is well provided for, spends the remainder of his substance in electrical experiments.
    His son, Bernard B. Stubblefield, 14 years of age, has for four years been his father's sole assistant. He is a remarkable boy. His father has been his only educator, and the lad is now an expert electrician and reads abstruse works on electricity and technical electrical journals with the same zest that other boys read stories of travel and adventures. His father says of the boy that he would be able to carry out and finish his system of wireless telegraphy should the father die, so closely has he been allied with every step in its discovery and development.
    In order to protect his right of first discovery in the absence of a patent Stubblefield has described his invention in a document which he has filed with the clerk of Calloway County. This document is backed by the testimony of J. C. McElrath, A. D. Thompson, James M. Cole, James Coleman, S. Higgins, Charles Jetton, O. T. Hale and Vernon Blythe, who declare that they have examined his apparatus and that it performed all the inventor claims for it; that they received telephone messages from varying distances without the aid of wires, and that they are positive the test was conducted without deception of any description. These men are accounted among the best in Calloway County. One of them is the postmaster of Murray, the others are lawyers, doctors, merchants and public officers.

By  NATHAN  STUBBLEFIELD.
I  HAVE been working for this, ten or twelve years, he said. Long before I heard of Marconi's efforts, or the efforts of others, to solve the problem of transmission of messages through space without wires, I began to think about it and work for it. This solution is not the result of an inspiration or the work of a minute. It is the climax of the labor of years of days and nights of thought, of hundreds of hours of experimenting.
    Of course I worked along the lines all the others are working. The earth, the air, the water, all the universe, as we know it, is permeated with the remarkable fluid which we call electricity, the most wonderful of God's gifts to the world, and capable of the most inestimable benefits when it is mastered by man. For years I have been trying to make the bare earth do the work of the wires. I know now that I have conquered it. The electrical fluid that permeates the earth carries the human voice, transmitted to it by any apparatus, with much more clarity and lucidity than it does over wires. I have solved the problem of telephoning without wires through the earth, as Signor Marconi has of sending signals through space. But I can also telephone without wires through space as well as through the earth, because my medium is everywhere.
    How I have obtained this result is, of course, my secret. My apparatus has not yet been patented. In that small box that you have seen lies the secret of my success. It is not yet perfect, by any means. I can now telephone a mile without wires. When the larger apparatus, on which I am now working, is finished I will demonstrate that messages can be sent much further--how far I cannot say. The system can be developed until messages by voice can be sent and heard all over the country, to Europe, all over the world. There is nothing to stop it. The world is its limits. This may seem like boasting. It is not. It is a fact.
    Beneath the surface of the earth, as above it, there is electricity. No one knows how deep it extends or how high it goes. As one throws a pebble into a pond and agitates it into circles that grow and extend to every edge. The apparatus that I have invented agitates the electric fluid in the earth. The voice projected into my transmitter agitates or vibrates the electricity in the earth, which extends beyond in every direction, and the vibrations reproduce the sounds in receivers tuned to convey them to the listening ear. What this apparatus consists of, or how it does its work, I will not tell.
    That it does all that I claim for it now, ample tests have proved. In a short time, when my improved and more powerful apparatus is finished, I will make another test, and expect to be able to telephone several miles. Then I will go to Washington and patent my invention, which will also be protected in all countries having patent laws. I will then, also, seek capital with which to further develop my discovery.
    As to the practicability of my invention, all that I claim for it now is that it is capable of sending simultaneous messages from a central distributing station over a very wide territory. For instance, any one having a receiving instrument, which would consist merely of a telephone receiver and a few feet of wire, and a signaling gong, could, upon being signaled by a transmitting station in Washington, or nearer, if advisable, be informed of weather news. My apparatus is capable of sending out a gong signal, as well as voice messages. Eventually it will be used for the general transmission of news of every description.
    I have as yet devised no method whereby it can be used with privacy. Wherever there is a receiving station the signal and message may be heard simultaneously. Eventually I, or some one, will discover a method of tuning the transmitting and receiving instruments so that each will answer only to its mate.
    I claim for my apparatus that it will work as well through air and water as it does through the earth. That it will convey messages between the land and sea, for instance, from lighthouses to ships, from vessels in any part of the ocean to vessels or their owners on land if each carry my transmitters and receivers; it can be used on moving trains so that they may be spoken between stations and thus prevent accidents. There is no conceivable position or station in which they may not be used. The all enveloping electricity, the medium of carriage, insures that.
    Of course my system demands development, which, in turn, demands time and money. But I have accomplished the fact. I can telephone without wires, a mile or more now, and with more powerful apparatus and further development, everywhere. The curvature of the earth means nothing to me--it will not deter messages sent by my apparatus.
    I have shown you what my machine will do through the earth by grounding the wires. I will say that it is not absolutely necessary to ground the wires. I can send messages with one wire in the ground, the other in the air, or with no wires at all. In fact, my first and crude experiments were made without ground wires. I have sent messages by means of a cumbersome and incomplete machine through a brick wall and several other walls of lath and plaster without wires of any description. The present method of grounding wires merely insures greater power in transmission.
    Several years ago I invented an earth cell which derived enough electrical energy from the surrounding source to run a small motor continuously for two months and six days without being touched. There was enough energy in the motor to run a clock and other small pieces of machinery or ring a large gong. This earth cell can be greatly magnified. Its discovery was the beginning of my experiments with wireless telephony. The earth cell was merely buried in the ground and connected by wires with the motor. The earth's electrical currents supplied the power.
    The expense of my wireless telephony apparatus will not be great--not greater than that used for ordinary telephoning, minus the present enormous cost of wiring. As soon as I get the proper financial backing, which I am now looking for, I will proceed to develop my system. I can now telephone a mile or more without wires, and the expansion of my system is without limit.