National Electric Signaling Co. v. United Wireless Telegraph Co.

189 F. 727, 1911 U.S. App. LEXIS 5307
CourtU.S. Circuit Court for the District of Maine
DecidedSeptember 21, 1911
DocketNo. 643
StatusPublished
Cited by3 cases

This text of 189 F. 727 (National Electric Signaling Co. v. United Wireless Telegraph Co.) is published on Counsel Stack Legal Research, covering U.S. Circuit Court for the District of Maine primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
National Electric Signaling Co. v. United Wireless Telegraph Co., 189 F. 727, 1911 U.S. App. LEXIS 5307 (circtdme 1911).

Opinion

HALE, District Judge.

This suit in equity brings in question the .validity and the infringement by defendant of complainant’s United States patent, No. 706,736, applied for December 15, 1899, and granted to Reginald A. Fessenden August 12, 1902, for inventions in wireless telegraphy.

Nearly all that the world knows about wireless telegraphy has been found out within the last 10 years. Its present knowledge is small; but the method of operation commonly employed in the art is simple. The sending station consists of a wire high up in the air on a tall mast. It is like an insect’s feeler, and is called an “antenna.” It is electrically charged and discharged by an electric spark. Explosive waves then radiate in all directions through the all-pervading sub - stance called ether, just as light is radiated from the sun. These [728]*728waves proceed through space with the enormous speed of light, approximately 186,000 miles per second. As they proceed through the ether, they strike a receiving antenna raised up in the air like a feeler causing impulses to run down the wire to the earth. An instrument, interposed in this wire, causes an indicator to operate whenever an impulse passes, giving a signal by indicating dots and dashes. The device which responds to the waves striking the receiving antenna is called a “receiver.” It gives information that a wave has arrived. It includes also a “detector,” a device by which the electromagnetic waves cause the indicator to respond. Without such detector these waves cannot be seen nor heard nor felt.

In Marconi Wireless Telegraph Company v. De Forest Wireless Telegraph Company (C. C.) 138 Fed. 657, in 1905, Judge Townsend has described the Marconi invention, and has given the history of the art up- to that time. One of the complainant’s witnesses, Dr. Kennelly, professor of electrical engineering at Harvard University, an authority on the subject of wireless telegraphy, sets out in an interesting way the condition of the art at the time of application for the patent in suit:

“These invisible electromagnetic waves, upon which.modern wireless telegraphy depends, move ofl: through free space with the enormous, speed of light; and this speed is hardly diminished by the presence of the atmosphere. They present, however, many analogies t'o these more familiar waves of souu'd which are carried by the air, and which depend upon the presence of the air for their transmission.. Thus, the electromagnetic waves have a certain pitch or rate of vibration, like sound waves. A vertical wire of given dimensions and tension has, like a harp string, a natural pitch, or rate of vibration corresponding t'o its musical note. A sending mast wire at a wireless station has similarly a certain natural pitch or rate of vibration depending upon the length of the wire, the dimensions and distribution of the conducting surface, and the distribution of any other conductors, such as coils, which may be inserted in the path of the wire. The electrical pitch of such a sending mast wire is commonly very high, and it will emit' hundreds of thousands or millions of electrical vibrations per second; whereas, a harp string will ordinarily only emit hundreds or thousands of sound vibrations per second. The operation of electrifying the mast wire and then suddenly discharging it to ground by a spark across the gap corresponds electrically t'o plucking the harp string. It sets it into vibration.”

He- proceeds further to describe the receiving arrangements of the wireless telegraph system, as it existed at the date of the Fessenden application. From hís description it appears that the mast may be at any place within the sphere of influence of the sending station. This mast supports a wire insulated at the top where it may connect with the metallic surface, and is connected to the conducting surface of the ground at the foot of the mast. In the receiving mast wire is inserted a wave detector, sometimes called a circuit closer or sensitive tube. At the time of the application for this patent it was more commonly called a coherer, and its uses are fully pointed put by Prof. Kennelly;

“This detector, as described in the Marconi specifications, was essentially a gap or discontinuity in the 'electrical conducting path of the receiving mast wire; but which was capable, on the passage of an electromagnetic wave of ‘closing the circuit’ of a local voltaic-battery, and a telegraph receiving instrument, connected to the tube by the branch wires. Prior to the passage' [729]*729of an elect roma gnet if wave this detector, sensitive tube, coherer, or circuit closer would make a gap or open circuit, both in the path of the receiving mast, wire to the ground, and in the local circuit of the voltaic battery, the telegraph receiving instrument, and the wires. Consequently, the telegraphic receiving instrument would not respond, or would, give no signal, because the local battery had its current cut off at the coherer. When, however, an electromagnetic wave passed, by the mast and mast wire, it set up an electric impulse in the mast wire, tending io make a discharge from the latter to ground. This discharge would be prevented by the gap in the coherer. This gap contained loose particles of metallic powder lying in imperfect electrical contact with each other. The electric impulse in the receiving mast wire would, however, in trying to force its way io ground, through the coherer, build up an electric pressure or voltage at the gap containing the powder. If this electric pressure or voltage was strong enough, it burst its way through the powder, and. caused the particles of metal in the same to cohere, so as to form a good conducting path, and automatically ‘close the circuit’ of the voltaic battery and telegraph instrument' locally connected therewith; so that the telegraph instrument would indicate a signal. If. on the other hand, the electric impulse generated in the receiving mast wire on the passage of the electric wave was not strong enough to burst through the powder and break down the electric discontinuity in the coherer, then the telegraph receiving instrument in the local circuit failed to respond, and the wave went by undetected. In order to restore the coherer to it's original sensitive condition and disconnected state, after the telegraphic instrument recorded a signal, automatic means are shown and described in the Marconi patent for agitating the coherer at the same moment that the telegraph instrument gives its click of signal reception.”

The electric waves referred to are often called “Hertz waves” or “Hertz oscillations,” from the name of their discoverer, Heinrich Hertz. Judge Townsend describes the operation of these waves, and. thus refers to the action of the coherer:

“The powder in the tube, when in its normal condition, offers such an amount, of resistance that the local-battery current will not pass through it. But when the high-frequency oscillations or waves fall upon it. and surge up and down the elevated conductors, they effect such a transposition in the arrangement of the grains of powder, in a manner not entirely understood, as to weld them together, as it were: the result of which is that the grains resolve themselves into conductive paths, and the current passing through them attracts the vertical arm of the relay, which, contacting with the two points below, permits the current to pass around through the battery, to the telegraph instrument, which records the dash or dot as transmitted and received from the transmitting station.

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Related

Kintner v. Atlantic Communication Co.
230 F. 829 (S.D. New York, 1916)
National Electric Signaling Co. v. Telefunken Wireless Telegraph Co.
193 F. 424 (U.S. Circuit Court for the District of Southern New York, 1911)

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Bluebook (online)
189 F. 727, 1911 U.S. App. LEXIS 5307, Counsel Stack Legal Research, https://law.counselstack.com/opinion/national-electric-signaling-co-v-united-wireless-telegraph-co-circtdme-1911.