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John Stone Stone, physicist, (b: September 24, 1869 d: May 20, 1943 Dover, Va. San Diego, Calif), began his career as a telephone engineer and found it a natural step into the field of wireless, which at the opening of the century was attracting electrical engineers as California did prospectors in 1849.

General Charles Pomeroy Stone was in the Union Army during the Civil War, and it was while campaigning in the Mississippi Valley that he met Miss Jeannie Stone, a southern girl. The duplication of names explains why their son John Stone Stone was so baptized.

In later years General Stone was chief of staff for the khedive of Egypt, having been officially designated by the United States on January 27, 1943, upon presentation of the John Fritz Medal by AIEE. government. During his son's boyhood, he traveled through many countries bordering on the Mediterranean, which accounts for the fact that John was as fluent in French and Arabic as he was in English

John's education in America was obtained at the Columbia Grammar School, New York City, at the Columbia School of Mines (two years) and at Johns Hopkins University (two years) from which he was graduated in 1890. For the next nine years he was with the Research and Development Laboratory of the American Bell Telephone Company at Boston, Massachusetts, where his exceptional ability in mathematical analysis came into full play.

Among his early inventive achievements were the Stone common battery system for telephony, the use of uniformly spaced inductance coils for loading telephone wires and a carrier current system of transmission over wires.

Stone's special study of electrical oscillations and radiation at Johns Hopkins, and his further study of the work of Professor Elihu Thomson, Nikola Tesla and others along the line of electromagnetic waves, led H. V. Hayes, chief engineer of the Telephone Company, to ask him to investigate the possibility of transmitting speech telephonically by Hertzian waves without the use of wire conductors.

Stone made a masterly report of this work. He also filed patents covering his work on carrier current, or wired wireless, as it was termed later.

Stone did not have wireless particularly in mind when in 1899 he set himself up as consultant, but ensuing events forced his hand. His first client was Herman W. Ladd, who had developed a method of radio direction finding based on a cylindrical metal screen around a vertical receiving antenna.

The screen had an up-and-down slit through which electric waves were supposed to strike the antenna as the screen rotated. Stone had two stations set up to test the contraption, and while working on it became so interested in wireless telegraphy that before long he had taken it up as his major effort.

It became more and more evident to him that the wireless needed sharper tuning. This, and his practical work with Ladd's apparatus, finally brought him into the wireless telegraph fold, and in the summer of 1899 he conceived a system of selective wireless communication.

Stone applied for a patent on tuning on February 8, 1900, and it was allowed February 2, 1902 (No. 714,756). This was a year and a half before the grant of Marconi's American patent No. 763,772 on tuning. Stone's arrangement featured a four circuit wireless telegraph apparatus substantially like that later specified and patented in America by Marconi, who had previously been granted an equivalent British patent, the famous No. 7,777.

Stone's patent described adjustable tuning, by means of a variable inductance, of the closed circuits of both transmitter and receiver.

It also recommended that the two antenna circuits be so constructed as to be resonant to the same frequencies as the closed circuits. Stone made it clear that he had found it was possible not only to originate high frequency oscillations in a circuit, and to determine their frequency by proper choice of capacity and self inductance in the circuit, but also to transfer those oscillations to another circuit and retain their original frequency.

In those days, spark transmitters were closely coupled, and hence were broadly tuned so that overlapping of waves caused interference. At the transmitter, Stone took advantage of loose coupling, bringing about the emission of a single, sharply defined wave. The use of loading coils as swamping inductances was also a feature of his system. His receivers likewise embodied loose coupling, and included an intermediate weeding-out circuit, which greatly enhanced selectivity.

To make these ideas and developments available as apparatus, Stone formed the Stone Wireless Telegraph Syndicate in 1901, which was followed soon after by the Stone Telegraph and Telephone Company.

Stone's methods revolutionized spark telegraphy in the United States, particularly at government stations. Soon his ideas as to the emission of a single wave, and his requirements as to selectivity, were made a part of specifications for government purchased wireless equipment. Almost all of the older sets in service, particularly in the United States Navy, were changed over to loose-coupled types.

In 1905 the Navy contracted for the Stone system to be installed at the navy yards at Boston, Massachusetts, and Portsmouth, New Hampshire, and for the first time these stations were so sharply tuned that a relay station between the two Navy yards was no longer necessary.

Another early investigation of the Stone Company was in the field of marine radio direction finding, but tests revealed that while the bearings were accurate, the method was not practical. It remained for F. A. Kolster, who assisted in the tests, to develop a workable system of direction finding for the Navy about nine years later.

In the story of radio, there is registered a historic day in the autumn of 1912, when De Forest, with the assistance of his old friend John Stone Stone, demonstrated the audion as an audio amplifier to engineers of the American Telephone and Telegraph Company. They proved that although weak and imperfect, and incapable of carrying any considerable voice load without a blue haze forming inside the bulb, nevertheless, the audion was capable of amplifying speech.

Stone, one of the leaders in the formation of the Institute of Radio Engineers, was a director of the Institute in 1912, vice president in 1913.14, and president in 1914-15. He was awarded the Edward Longstreth Medal of the Franklin Institute in 1913 for a paper on the practical aspects of the propagation of high frequency waves along wires, and the Medal of Honor of the Institute of Radio Engineers for distinguished service in radio communication in 1923.

He had obtained about 120 patents on telephonic and radio subjects in the United States, as well as a similar number in foreign countries.

Stone was a gentleman of the old school, a deep thinker, and one of the most practical mathematicians in the field of radio. His calculations and analysis went so deep into mathematics that we could never follow him, said an associate, but Nature always agreed and confirmed his findings.

Said the Institute of Radio Engineers in tribute:

Very much of an individualist, possessed of an interesting personality, of an artistic temperament, a gracious sense of humor, and a very high sense of honor, Stone lived a good life. Well trained technically and given to the classical scientific method of analysis as it were, Stone was one of the last of the pioneers who witnessed the very inception of radio and gave his whole life to it and lived to see it flower into a great industry.

Source: Orrin E. Dunlap Jr., Radio's One Hundred Men of Science

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