rules of the patent law, as the inventor has of the force of nature with which he was dealing, and of the means by which he reduced that force to a practical use. The patent is clearly not intended to be limited to a form of apparatus, but einbraces a method or process. This is apparent upon the face of the specification. The inventor begins by saying:

"My present invention consists in the employment of a vibratory or undulatory current of electricity in contradistinction to a merely intermittent or pulsatory current, and of a method of and apparatus for producing electrical undulations upon the line wire."

After describing the advantages of an undulatory current, resulting from gradual changes of intensity, over a pulsatory current caused by sudden changes of intensity, he says:

"It has long been known that when a permanent magnet is caused to approach the pole of an electro-magnet, a current of electricity is induced in the coils of the latter, and that, when it is made to recede, a current of opposite polarity to the first appears upon the wire. When, therefore, a permanent magnet is caused to vibrate in front of the pole of an electro-magnet, an undulatory current of electricity is induced in the coils of the electro-magnet, the undulations of which correspond, in rapidity of succession, to the vibrations of the magnet, in polarity to the direction of its motion, and in intensity to the amplitude of its vibration."

He further says:

"There are many ways of producing undulatory currents of electricity, dependent for effect upon the vibrations or motions of bodies capable of inductive action. A few of the methods that may be employed I shall here specify. When a wire, through which a continuous current of electricity is passing, is caused to vibrate in the neighborhood of another wire, an undulatory current of electricity is induced in the latter. When a cylinder, upon which are arranged bar magnets, is made to rotate in front of the pole of an electro-magnet, an undulatory current of electricity is induced in the coils of the electro-magnet. "Undulations are caused in a continuous voltaic current by the vibration or motion of bodies capable of inductive action, or by the vibration of the conducting wire itself in the neighborhood of such bodies. Electrical undulations may also be caused by alternately increasing and diminishing the resistance of the circuit, or by alternately increasing and diminishing the power of the battery. The internal resistance of a battery is diminished by bringing the voltaic elements nearer together, and increased by placing them further apart. The reciprocal vibration of the elements of a battery, therefore, occasions an undulatory action in the voltaic current. The external resistance may also be varied. For instance, let mercury or some other liquid form part of a voltaic circuit, then the more deeply the conducting wire is immersed in the mercury or other liquid, the less resistance does the liquid offer to the passage of the current. Hence the vibration of the conducting wire in mercury or other liquid included in the circuit occasions undulations in the current. The vertical vibration of the elements of a battery in the liquid in which they are immersed produces an undulatory action in the current by alternately increasing and diminishing the power of the battery."

...

The inventor adds this explanation:

"In this specification the three words 'oscillation,' 'vibration,' and 'undulation' are used synonymously, and in contradistinction to the terms 'intermittent' and 'pulsatory.' By the term 'body capable of inductive action,' I mean a body which, when in motion, produces dynamical electricity. I include in the category of bodies capable of inductive action, brass, copper, and other metals, as well as iron and steel."

His fifth and final claim is of

"the method of and apparatus for transmitting vocal or other sounds telegraphically, as herein described, by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sounds, substantially as set forth."

In this claim, as throughout the specification, the word "method" is evidently used, not as synonymous with "mode" or "apparatus," but as equivalent to "process"; just as it was used by Chief Justice Taney, delivering the judgment of the majority of the court, in Morse v. O'Reilly, 15 How. 62, 117, as well as by Mr. Justice Grier (who dissented in Morse v. O'Reilly) in delivering the unanimous judgment in Corning v. Burden, 15 How. 252, 267. And the invention claimed is not merely the apparatus described, but also the general process or method, by which the wind, or a musical instrument, or the human voice, produces in a current of electricity a succession of electrical disturbances, not sudden and intermittent or pulsatory, but gradual, oscillatory, vibratory, or undulatory, so as to give out at the further end of the conducting wire sounds exactly corresponding in loudness, in pitch, and in tone, character or quality, to the sounds committed to it at the nearer end.

The opinion in Spencer's Case clearly points out that "Bell discovered a new art that of transmitting speech by electricity and has a right to hold the broadest claim for it which can be permitted in any case," and "the invention is nothing less than the transfer to a wire of electrical vibrations like those which a sound has produced in the air"; and that his patent, while not covering the abstract principle, without regard to means, of transmitting speech by electricity, yet is not limited to a particular form of apparatus, but includes the process or method (using the two words as equivalent), the essential elements of which are "the production of what the patent calls undulatory vibrations of electricity to correspond with those of the air, and transmitting them to a receiving instrument capable of echoing them."

The evidence in this case clearly shows that Bell discovered that articulate sounds could be transmitted by undulatory vibrations of electricity, and invented the art or process of transmitting such sounds. by means of such vibrations. If that art or process is (as the witness called by the defendants say it is) the only way by which speech can

be transmitted by electricity, that fact does not lessen the merit of his invention, or the protection which the law will give to it. The mode or apparatus by which Bell effects his purpose is by using an electromagnet in the transmitter, and another electro-magnet in the receiver. But the essence of his invention consists not merely in the form of apparatus which he uses, but in the general process or method of which that apparatus is the embodiment. Dolbear likewise uses an electromagnet in the transmitter; and both his method and his apparatus, as is admitted in his own affidavit, are substantially like Bell's, until he comes to the receiver. For the magneto-receiver, Dolbear substitutes a condenser-receiver, consisting of two thin metal diaphragms or disks, of about the size and thickness of those used in an ordinary Bell telephone, separated by a very thin air space, one or both disks connected with the conducting wire, and the speaking disk, if not so connected, otherwise charged with electricity; so that, as the varying currents flow into and out of this condenser, the two disks attract one another more or less strongly, and thereby vibrations are set up which correspond to the vibrations of the original sound.

The main difference on which the defendants rely is that Bell uses what is called dynamic electricity, producing by its motion an electric current; while Dolbear, in his receiver, uses what is called static electricity, producing, while at rest, electrical attraction. And the learned counsel for the defendants illustrate the distinction thus:

"It was known long before Bell's method that electricity had two properties, very much as water has two properties; namely, first, pressure or head, or that property which tends to make it flow, and which can exist by itself only in the case of an insulated and charged body, or a reservoir of water; and, secondly, that dynamic property arising from its motion, and which can never exist by itself, but depends upon the quantity in motion and the rate of motion. This is not an absolutely exact way of expressing it, for the reason that electricity is not a fluid; but, were it a fluid, the statement would be entirely exact."

It does not appear to us to be important to determine whether, in scientific exactness, the varying influences of static electricity may properly be called currents; or whether the two properties of electricity differ in kind and in substance, or only in degree, or in the form of manifestation and application; or whether the force of the property which tends to make a fluid, when stationary, change its place and flow, is different in kind from that which it exerts when changing its place and flowing; in short, whether the power of the pressure of water in a reservoir is different in kind from water-power in a stream or current. Whatever name may be given to the property, or the manifestation, of the electricity in the defendants' receiver, the facts remain that they avail themselves of Bell's discovery that undulatory vibrations of electricity can intelligibly and accurately transmit articulate speech, as well as of the process which Bell invented, and by which he reduced his discovery to practical use; that they also copy the mode

and apparatus by which he creates and transmits the undulatory electrical vibrations, corresponding to those of the air; and that in the plate charged with electricity, which they have substituted for the magnetic coil in the receiver, the charge constantly varies in accordance with the principle which Bell discovered, and by means of the undulatory current caused by the process, and in the mode which he invented and patented.

The defendants have therefore infringed Bell's patent by using his general process or method, and should be restrained by injunction from continuing to do so; and it is unnecessary, for the purposes of this decision, to consider whether the defendants' apparatus is a substantial equivalent of the plaintiff's, or whether it is an improvement for which Dolbear might himself be entitled to a patent. Temporary injunction ordered. 1

224. HOTCHKISS v. GREENWOOD

SUPREME COURT OF THE UNITED STATES. 1850

11 How. 248

THIS case was brought up, by writ of error, from the Circuit Court of the United States for the District of Ohio. It was a question involving the validity of a patent right, under the following circumstances. The patent and specification were as follows:

"The United States of America, to all to whom these letters patent shall

come.

"Whereas John G. Hotchkiss, New Haven, Conn., John A. Davenport, and John W. Quincy, New York, have alleged that they have invented a new and useful improvement in making door knobs, of all kinds of clay used in pottery, and of porcelain, which they state has not been known or used before their application.. These are therefore to grant, according to law, to the said John G. Hotchkiss, John A. Davenport, and John W. Quincy, their heirs, administrators, or assigns, for the term of fourteen years from the 29th day of July, 1841, the full and exclusive right and liberty of making, constructing, using, and vending to others to be used, the said improvement, a description whereof is given in the words of the said Hotchkiss, Davenport, and Quincy, in the schedule hereunto annexed, and is made a part of these presents.

"In testimony whereof, I have caused these letters to be made patent, and the seal of the Patent-Office has been hereunto affixed. Given, under my hand at the city of Washington, this 29th day of July, A. D. 1841, and of the independence of the United States of America the sixty-sixth.

"DANIEL WEBSTER,

Secretary of State.

"Countersigned and sealed with the seal of the Patent-Office.

"HENRY L. ELLSWORTH,

Commissioner of Patents."

1 [Affirmed in Telephone Cases, 1887, 126 U. S. 1.]

In October, 1845, the plaintiffs in error brought an action in the Circuit Court of the United States for Ohio, against the defendants for a violation of the patent right.

The defendants pleaded not guilty, and gave the following notice:

"The plaintiffs will please take notice, that on the trial of the above cause the defendants will give in evidence to the jury, that said John G. Hotchkiss, John A. Davenport, and John W. Quincy were not the original and first inventors and discoverers of making or manufacturing knobs of potter's clay or of porcelain. . . .

And the evidence being closed, the counsel for the plaintiffs insisted in the argument, that, although the knob, in the form in which it is patented, may have been known and used in the United States prior to their invention and patent; and although the shank and spindle, by which it is attached, may have been known and used in the United States prior to said invention and patent; yet, if such shank and spindle had never before been attached to a knob made of potter's clay or porcelain, and if it required skill and thought and invention to attach the said knob of clay to the metal shank and spindle, so that the same would unite firmly, and make a solid and substantial article of manufacture, and if the said knob of clay or porcelain so attached were an article better and cheaper than the knob theretofore manufactured of metal or other materials, that the patent was valid, and asked the Court so to instruct the jury, which the Court refused to do; but, on the contrary thereof, instructed the jury, that, if knobs of the same form, and for the same purposes with that described by the plaintiffs in their specifications, made of metal or other material, had been known and used in the United States prior to the alleged invention and patent of the plaintiffs, and if the spindle and shank, in the form used by the plaintiffs, had before that time been publicly known and used in the United States, and had been theretofore attached to metallic knobs by means of the dovetail and the infusions of melted metal, as the same is directed in the specification of the plaintiffs to be attached to the knob of potter's clay or porcelain, so that if the knob of clay or porcelain is the mere substitution of one material for another, and the spindle and shank be such as were theretofore in common use, and the mode of connecting them to the knob by dovetail be the same that was theretofore in use in the United States, the material being in common use, and no other ingenuity or skill being necessary to construct the knob than that of an ordinary mechanic acquainted with the business, the patent is void, and the plaintiffs are not entitled to recover. . . .

...

The case came up to this Court, and was argued by Mr. Ewing, for the plaintiffs in error, and Mr. Chase, for the defendants in error.

Mr. Ewing, for the convenience of reference, divided the instructions of the Court into paragraphs.

.

The Court seem to have been of opinion, first, that it could not, in