US1262491A - Method of and apparatus for translating electrical variations. - Google Patents

Description

P. C. HEWITT. I

METHODOF AND APPARATUS FOR TBANSLATING ELECTRICAL VARIATIONS.

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INVENTOR WIT/158858 a,

P. C. HEWITT.

METHOD OF AND APPARATUS FOR TRANSLATING E LECTRICAL VARIATIONS.

APPLICATHN FILED MAY 15. 1915.

1 62 49 1 Patented Apr. 9 1918.

2 SHEETS-SHEET 2.

WITNESSES INVENTUR I BY 7 W 9? 1 MAT/VINE) shape,

Y and the initial density UNITED STATES PATENT OFFICE.

PETER COOPER HEWITT, OF RINGWOOD MANOR, NEW JEIBiSEYy-ASSIGE'OR TO COOPER. HEWITT ELECTRIC COMPANY, 0E HOBOKEN, NEW JERSEY, A CORPORATION OF NEW JERSEY.

METHOD OF AND APPARATUS Eon. TRANSLATING ELECTRICAL VARIATIONS.

Specification of Letters Patent.

Patented Apr, 9, 1918} Original application filed March 30, 1907, Serial No. 365,597. Divided and this application filed May 15,

1915. Serial No.28,435.

To all whom it may concern:

Be it known that I, PETER CooPER HEWITT, a citizen of the United States, and

resident of Ringwood Manor, in the county of Passaic and State of New Jersey, have invented certain new and useful Improvements in Methods of and Apparatus for Translating Electrical Variations, of which the following is a specification.

My present invention involves the discovery of certain phenomena developed by the flow of electric current through a gas ;or vapor, and it particularly concerns the utilization of such phenomena in connection .with electrical variations of all kinds and for various purposes. I

It is useful in connection with very rapid and very feeble electrical variations, and is particularly adapted to translate variations of potential. When used for detecting the oscillations in the receiving circuit of a space telegraph or telephone system, the results demonstrate extreme sensitiveness, re-

liability and durability.

My invention contemplates the employ ment of one or more special or auxiliary terminals, or electrodes, in operative relation to a gas or vapor carrying current, said current being supplied to the gas'independently of such auxiliary terminal or terminals.

The geometrical characteristics of the conducting vapor may be determined by the size, etc., of a containing vessel and by the size and position of electrodes therein.

The electrical characteristics of the gas .or a

vapor are dependent upon the geometrical characteristics, upon the kind and purity of the gas or vapor, upon the nature and material of the electrodes, of the vapor. The density of the vapor depends upon the temperature and pressure,

ture during operation are. dependent upon the ratio of heat generation to heat radiation. The internal heat generatlon is dependent upon the above mentioned electrical are sensitive to magnetic action.

and upon the density of a given vapor 1I1 characteristics'and upon the amount of current flowing in the vapor device. The heat radiation is dependent upon the heat radiatmg area and. the temperature of the surround'ngs. Hence, in the operation of a vapor evice having given geometrical and electrical characteristicsof construction, the density of thevapor is controllable by regulating current flow, heat radiating area, and

temperature of the surroundings.

The reactions attending passage of current in a conducting gas or vapor maybe subdivided into three definite classes; (1) reactions at and near the positive electrode or anode; (2) reactions in the gas or vapor itself; and (3) reactions at and adjacent the negative electrode, or cathode, including reactions at the junction of the negative dark space with the vapor carrying current from the main positive electrode,

The separate phenomenaof which the reactions at the positive electrode or anode are made up, are numerous, and are chiefly modified by the position,size, and physical state of the anode; and by the purity, density, and kind of gas; and also by current density in the gas. Certain of them One of the visible reactions of the positive electrode or anode, is a luminous ball or bush which is very sensitive to magnetic action and which tends to be a sourceof variation. At low densities it is very sensitive tomagnetic action. a

The reactions in the conducting vapor itself and modifications thereof, independent of the reactions near the electrodes, have been broadly stated by me. They may be modified by a magnet, especially at low densities. The reactions Yof the vapor column are normaly stable, and for purposes of this invention, its length, the kind of gas, the gas density, and the current density are chief modifying factorsv to be considered and controlled; Y The phenomena at the negative electrode are numerous, and include two distinct classes; one class being those found at the negative electrode when it is in its primary condition, before it has been changed to I What has been termed by me its low resistance or broken down state, and another class beingthose which existafter the negative electrode has attained the low resistance stat-e. lit is characteristic of the first mentioned class that on subjecting the negative electrode in the primary condition, to sufficient electrical stress, a certain point is reached where a leakage current may be observed under certain conditions. A modified leakage current flowing under low stress is manifest when said electrode is present in, a current carrying vapor having suflicient current density. The opposition or apparent resistance to this leakage current, is modified by the surface area of the electrode, and by the current density in the vapor adjacentthereto, and it varies, in ways peculiar to itself with the nature, purity and the density of the vapor, and with the nature and condition of the electrode. It varies with the temperature of the negative electrode, and if this temperature be increased to incandescence, this resistance then reaches or comes near its minimum limit. After the last state of resistance in the primary condition has been reached, if the temperature of the electrode be increased to such a point as to bring about "a physical or chemical change of state of the electrode, while current, with suficient backing, is passing into said elec trode, the reactions will change to those of the second class; namely, those attendant upon the broken down state of resistance, and the reactions of the negative electrode. will then be measured by a less drop in potential. It is often desirable that the drop over the device should be as small as possible and in such case this latter state should serve best. This broken down state of the negative electrode may be attained by various expedients now well known in the art.

Accompanying this change are thevisible phenomena of the negative flame to which I have before called attention. The visible phenomena consist of a bright spot on the negative electrode with a flame apparently hovering over this spot. The peculiar haracteristic of this flame is that it ten s to lie'in' and along the magnetic lines of force, rather than to be twisted or distorted by them, as is usual to current passing. It tends normally to project itself perpendicularly from the surface of the electrode. A magnet may be used to modify or adjust the conditions at the negative electrode. The bright spot tends to locate itself at a meniscus of an irregularity on anelectrode. The flame itself is surrounded by a dark space and when the flame is in normal position in a right line with the vapor column, the top of the flame usually marks the boundary of the dark space where it joins the luminous positive column of conducting vapor coming from the positive electrode.

nacaeei The flame is very sensitive to electrical variations, and such variations may be ob served when looking at it. Its reactions -may also be varied by a magnetic field and its reactions may be made usable in this way. When the positive electrode is ar-' ranged at comparatively short distances from the negative electrode as, for instance, when located within the dark space, there may be no luminous positive column, and the reactions at the positive are modified at certain distances from the cathode and may be rendered practically unnoticeable. The positive bush reaction may be' practically eliminated by these means. The lengthof the vapor column is decreased so that the total voltage drop across the device is decreased, and the drop due to the positive bush may be seriously modified it not altogether eliminated. Many of the above described reactions are modified by rapid electrical variations and are useful in connection with them.

In the practice of my invention T expose.

within the vapor device, supplied with current through main electrodes, a separate terminal ortwo or more terminals operatively associated with a telephone or other indicat- 'ing instrument and with a source of variaterminal of this type, seem to vary with the charge in the body of the vapor, particularly in the region immediately adjacent such auxiliary terminal. The current density in the vapor varies with the total amount of current flow between the main electrodes and also with the relative position or location of the auxiliaryterminal with refer ence to the main electrodes and the current path between said electrodes. Hence, for given conditions, the proper current density or charge of the vapor adjacent an auxiliary terminal, may be attained by adjusting or arranging the auxiliary terminal nearer to or farther from the main electrodes and the path between them, or, where the auxiliary terminal is already fixed in a suitable position, by increasing or decreasing the amount of current flowing between the main electrodes. The latter expedient) will usually have the eflect of changing the density and nal will have .an effect somewhat analogous to increase of charge or current density in the body of vapor adjacent thereto.

By increasing the main current when re- 5 ceiving even faint signals, the volume of the signal may be amplified in many arrangements of this devlce, and this may be continued up to the point where they begin to be obscured by other variations developed.

\Vhatever type of device be employed for maintaining the supply of current in the vapor, such supply should be independent "of the auxiliary electrode used for detecting purposes. An auxiliary electrode, because 1'5 of its position or electrical connections, may

have-a tendency to be a positive or a negative electrode with reference to thevapor,

or, being maintained at a neutral point, as by a source of eounter-electromotive force, or by a condenser which may be used as such, it may under certain conditions tend to act as either, or alternately,-as both. For some purposes it is preferable that it be arranged so as normally to have no current flowing either from or to it, except such currents as are the result of the action of the electrical variations to be detected, and in case it is desired that the device should have a rectifying action, the auxiliary electrode should tend to oppose a prohibitive barrier to the passage of current from the vapor into it. This action seems to be more complete when the current flow in the vapor adjacent to it is at or near a minimum and its surface area is not too great.

The reactions at the positive electrode are normally in an unstable state and. give rise to rapid electric variations, which when heard in a telephone are rumbling, rattling,

cracking sounds, and may, under certain conditions, produce clear musical notes. One means of rendering the reactions at the main positive electrode substantially stable, is to bring such main positive electrode in close proximity to the main negative electrode. In such case, the visible phenomena at the main positive electrode and the voltage drop, are modified and largely suppressed, and the attendant reactions may be so rendered practically noiseless to a telephone at an auxiliary electrode.

The size of the positive electrode is im portant with reference to the heating effect on it and also with respect to the bush reaction, and for most purposes it shouldbe'of sufficient area to pass the desired maximum current without becoming unduly overheated but it should not be'too large on account of the bush reaction. It may be designed to be highly heated and its temperature may be made to affect the reactions at the negative electrode, as well as its own.

The vapor column, considered by itself,

rarely presents any sources of irregular or detrimental electrical variation. It is desirable to use means to-maintain theeurrent the vapor normally constant and unlform 1n quantity and in distribution.-

device. The desired direction and distribution of the lines of force'of the field may be established by proper design and location of a single magnet, or a plurality of magnets may be used to establish a resultant field. With a ring positive electrode, it is usually desirable to have the lines of force somewhere about 45 degrees from the normal direction of the negative electrode flame and with a disk positive electrode approximately parallel with such direction.

In all forms shown herein the conducting gas or vapor is inclosed in a suitable container preferably having three or more electrodes. The electrical reactions at the various electrodes and in the conducting' medium may be thus caused and controlled as desired, to enable the development of suitable reactions within the medium itself for the desired purposes and to make possible the modification and control of the reactions. The temperature and density of the gas or vapor may be controlled in any desired way, as by determining the area and disposition of the outer radiating surfaces of the container or by the use of suitable 6X- pedients for increasing or decreasing the heat absorbing or heat imparting power of the surroundings.

In all of the forms shown herein, the conducting medium is referred to as a gas or vapor medium contained between electrodes in a hermetically sealed vessel, but similar circuit connections may be made serv- 11a iceable in connection with other mediums having similar reactions. A pure gas is preferable, however, since it tends to insure uniformity of the reactions and I prefer to use a monatoniic gassuch as is afforded by mercury or mercury vapor in a hermetically sealed vessel or container. The container and any solid electrodes therein, are preferably of such material as not to yield gases under the conditions ofi operation. The methods of cleansing and evacuating such devices by washing with mercury vapor and exhausting the same while subjected to the action of heat and of the electric current, arenow well known in the art.

A starting band of the type well known in the art may be applied at a main negative electrode, as at C or an auxiliary electrode,

- as at C and may be used according to the practices well known in the art, or may be rying current supplied to the medium independently of the auxiliary terminal. In general the eircuits'whose reactions are to e utilized, should include differently conducting media afl'ording variable electrical, reactions of various classes, such as transition resistances etc. I prefer a true conductor of the first class, such-as ordinary conducting metals, and also a conductor of janother class of conductivity as, for inemployed to maintain normal current flow stance, one which is adapted to pass vcurrent after the manner of electrolytes or conducting fluids such as gases or vapors. A suitable source f electromotive force should be in the circuit of the fluid medium, said currentflow being preferably of relatively large quantity and low voltage. The indicator circuit parallel circuit including a part only of the fluid medium of-said first mentioned circuit.

The source of variations to tie-translated may be a circuit of either forced variations .or oscillatory variations and maybe an open circuit, connected to ground or. a. capacity, or not, as desired. vA closed circuit of either Y forced variations or oscillatory variations may be appliedto advantage'or. any of the arrangements shown in each'iand all of the 'figures of the drawings byfconnectinig the. two sides of such closedcircuit inthesame' waythat the aerials S and ground G re-j are connected, or in any; other do spectively sired way, all as will be well understoodby 7 those skilled in the art.

l have specifically shown and described herein only a few of thetypical andv ole-j] sirable ways of arranging the serial, indi: eating and direct current'supply circuits. From these it will be evident to one skilled in the art that my vapor devicev is so sensi tive that the variations to'be detected or; translated can hardly be applied to-the same in such manneras not to produce some efiect on the internal reactlons and that those reactions will produce more or less pronounced sensible effects in the indicator whenever the latter is applied to the vapor device in such manner that, impulses, direct currents, or displacement currents may through in response to potent al variations. The instrument should be desied or 10- cated so as not tobe injured by the amperage of such current flow, and, in general,

should be lateral or. branch or flow there 7 meager it is preferable to arrange the indicator and variation circuits in such manner that the variations to be detected may pass to the vapor device without being impeded or choked out by the indicator.

This is accomplished (by bringing the aerial receiving conductor or other desired source of variations, into operative relation to the vapor device by connecting it directly to one or more of the auxiliary electrodes, or by connecting it to a capacity area arranged in electrostatic relation to an auxiliary electrode or to the vapor path between it and the main electrodes. This may be done by employing a capacity'area in the form of a metal or tinfoil plate a foot or so in diameter, which is preferably located very close to the container, but it may be located some inches or even some feet away.

'Such' sheet or plate'is illustrated in my apas based on such embodiment of my invention, are contained in said application. In this application Tclaim the method and also certain special devices, combinations and elements not specifically claimed in said prior application, as for instance the capacity areaconsistingof a conducting band encircling the device adjacent an auxiliary electrode, in a manner analogous to the socalled starting band which is well-known in the art .as a meansfor electrostatically afi'ecting the main negative electrode of mercury vapor devices for starting flow of main current between the main electrodes.

7 In the accompanying drawing the container is shown in vertical section with the circuit connections thereof diagrammatically indicated,' the, figures correspond respectively-to F1gures2, 4,12,15,21 and 22 ofmy said prior application." The means for applying variations is shown as electro- "stati'cally" associated with the other elements "oftheapparatus,but-it will beobviousthat so far as concerns a certain aspects of thexin- 'ventions, the variations may be conductively applied.

Fig. lisa, view showing the electrostatic "band encircling an auxiliary electrode located between widely separated main elec-.

trodes, the negative electrode being pro- Mil vided withmeans for rendering more stable the reactions thereat.

Fig. 2 shows the aux1liaryelectrodeat the top of the container and the 7 positive electrode arranged close to thenetgative elee;

'trode in such manner as to rendrirmore stablethe reactions at the positiveelectrode;

Fig. 3 shows an arrangement in which thereare two ring electrodes adjacent to the negative electrode, one of them used as a main positive suitable regulatin electrode and the other used as an auxiliary electrode in connection with a second auxiliary electrode on the top of the container.

Fig. 4 shows a container substantially the same as in Flig. 2, associated with a typical indicator circuit.

Fig. 5 shows a similar container but having the auxiliary electrode in the form of a plate and associated with another typical receiving circuit. In this form the main positive electrode is adapted to heat a projection from the negative electrode.

Fig. 6 is a detailed view showing a modified arrangement may be used in the container of the preceding figures.

Fig. 7 illustrates a vapor device associated with a magnetic field and arranged in shunt to the condenser of a close tuned or resonant circuit, inductively associated with a primary source of variations.

In various of the figures of the drawings, electrodes of thin material having various outlines, are shown as viewed from a point above the planes of said electrodes, in order to show the structure more clearly. While any one of more of these electrodes may be arranged at various, similar or different angles, it is to be understood that these electrodes may be and preferably are arranged with their fiat surfaces lying in planes at right angles to the axis of the vapor device. In either case the device is preferably normally operated in a vertical position, but may be and frequently is operated in a tilted position as desired, in order to vary internal conditions for particular purposes or conditions.

In the various figures of the drawings, the specific devices embodying my invention comprise main positive and negative electrodes, one or more auxiliary electrodes, and a' su table container. The main electrodes are supplied with current from a suitable source, preferably a direct current source, indicated in the drawings as a storage battery. This supply circuit is provided with devices, including preferably an adjusta le ohmic resistance and an inductance which is also preferably adjustable. The ohmic resistance and the inductance may be more or less embodied in thesame device, but are preferably-sep arate. Suitable receiving and indicating circuitsare operatively associated with the auxiliary electrode.

Like parts have reference characters on the various fi been indicated by like res wherever this is possible without lia ility to cause confusion.

. Referring more particularly to Fig. 1, the positive electrode 1 may be any known or desired material suitable. for the purpose, such as iron, platinum, carbon, or other conof main electrodes which I 7 height.

ducting material. The particular cup shaped electrode shown in this and other figures, is preferably of the same material, size and shape as the positive electrode now in general use in the Cooper-Hewitt lamps.

The negative electrode 2 consists of a body of conducting liquid preferably of mercury. erably a solid conductor of iron, platinum, carbon, or other suitable material. The container 4 is preferably of glass, preferably hermetically sealed and preferably having a high vacuum when cold. It may be of any suitable or desired size, and may be conveniently made about 2-1/2 to 3 inches in diameter and about 5 or more inches in A device of such diameter and 7 inches in height will have a current carrying capacity through the main electrodes up to 4 or 5 amperes at pressures of, say, 7 to 25 .volts, and will have ample heat-radiating area.

The source of current supply is shown at 8, an adjustable resistance at 9, and an adjustable inductance at 10.- The supply cir cuit' is thus capable of regulationfor purposes of controlling the amperage through the lamp and for steadying the same to normally uniform values.

The auxiliary terminal 3 is sensitive to the electrical variations to be detected and these are operatively applied to the device from any suitable source of variation, as, for instance, a receiving wire S of a space telegraph or telephone system connected directly to the auxiliary terminal or brought in proximity to the device as by connecting it to the bend or collar C arranged adjacent thereto. It will be understood that the variations to be utilized, may be from other sources and may be of comparatively low frequency and greater amperage. Where the variations to be utilized are feeble or rapid, it is desirable to connect the supply wire S in electrostatic relation to the auxiliary electrode 3 so that there shall be little capacity or impedance in the supply circuit leading to the auxiliary electrode. The detecting circuit is preferably arranged to to the main positive or negative electrode or in a multiplicity of ways hereafter more fully referred to. In Fig. 1 it is shown connected to a capacity area G which for space signaling purposes need not be very The auxiliary electrode 3 is preflarge. A ground connection-C is sometimes desirable, but not always necessary, and may be made by connection from a main electrode as in Fig. 3, as desired.

In a vapor device of the kind shown in Fig. 1, any internally or1g1nated disturbing variations at the main electrodes, due to the passage of the battery current, W111 be manifest at the auxiliary electrode and tend to obscure its action when minute variations are to be detected. Hence in Fig. 1 I show the device provided with one of the various possible means for lessening the 1nternally originated disturbing variations, by renderingthe reactions at the main negatlve electrode more stable. This result 1s accomplished by arranging a projection 12 extending above the surface of the mercury 2 and wetted thereby, after the manner hereinbefore referred to. A platlnum wire projecting a short distance and having a diam-' eter of .045 inch, serves well for this purpose, for currents of from 1-1/4 to 2-1/2 amperes or evenmore.

Fig. 2 represents. a similar vapor device having the reactions at the negative electrode rendered stable in the manner just described, and embodying also a means for rendering stable the reactions at the positive electrode. In this form the positive electrode 11 is brought into close proximity to the negative electrode and arranged in the form of a ring symmetrically surrounding the projection 12 of the negative electrode, above and preferably parallel with the surface of the mercury 2 and preferably slightly above said projection. If the ring is used in the form of a flat disk of iron 1-1/8 inches in external diameter and 1/4 inch or less in internal diameter, it will pass 2-1/2 to 3 amperes of current without becoming unduly heated.

The internal diameter of the ring should not be too great with respect to its distance from the projection 12, for otherwise there may be a tendency to unstable reactions giving rise to disturbing fluctuations. Ring electrodes of the above specified sizes, however, carrying currents as described, are very.

suitable for the purpose, but this electrode may be varied in size and shape and may be. a disk or other shape.

A'convenient method of determining or adjusting the distance of such a' positive electrode from the surface of the mercury consists in providing the container with 'a pocket 15. adapted to contain an extra supplyof mercury 16. In such a device the" desired amount 0 mercury may be poured or. from the negative electrode into the pocket, or vice versa.

conveniently efiected by shaking the device so that the mercury of the negative electrode acaeei tive electrode, thereby making and breaking a bridge.

With the above described. arrangements, the visible phenomena at the main positive electrode and its resistance are modified and largely suppressed and the attendant disturbing reactions are made practically unnoticeable so far as concerns their efi'ects at the auxiliary electrode and in the indicator connected thereto. "The device may beoperated at a lower potential than that of F 1g. 1 and it has a much greater current capacity, the latter being limited, in practice, mainly by the size and fusibility of the positive electrode.

The heating efi'ect at the positive electrode is less as the surface of the positive electrode is increased, and this arrangement may be used to carry current up to 5 amperes at a voltage of 7 to 10 or 12 volts, depending upon the characteristics of the particular device. The operation of this form of device,

under varying conditions, seems to vary with the position of the positive electrode with respect to the negative electrode, particularly for positions varying from barely out of contact with the surface of the mercury to, say, 5/8 inch or more from the surface of the mercury.

In this case also, the wireless or other source of variations is connected directly to the electrostatic band adjacent the auxiliary terminal. In this figure, as also in Figs. 3, 4 and 7, the upper cup shaped terminal is used asan auxiliary electrode but, as in the case of Fig. 1, the electrostatic band or strip is located so as to inclose the active part of lizihpdelectrode in an encircling electrostatic In Fig. 3 there are two ring electrodes 31, 32 located one above the other. There is also a cup shaped electrode 13'at the top. Either one of the ring electrodes or the cup shaped electrode may be used as the main positive or as auxiliary electrode or electrodes. 7

When the upper ring-electrode 32, is not used as a main electrode, it appears to serve some useful purpose with reference to the reactions occurring at the main electrodes. One apparent effect is that it tends to preventadherent deposits on the walls of the container, which otherwise frequently occur and which appear to be caused by exfoliations from the trode.

In this figure the indicator connection is from the upper cup shaped auxiliary electrode 13, to the lower ring electrode 31, f which is located in the dark space between, In this form of device the starting may be and adjacent to. the main electrode, the upper ring electrode 32 being used as a point 12 of the negative elec main positive electrode. The indicator is located in a circuit connected between this 'ations are all substantially as in Fig. In Fig. 4, however, the indlcatrng circuit isfrom the auxiliary cup shaped electrode at the top of the container, through the indi-' cating device to the negative electrode 2, as shown. The indicator R may be an electromagnetic telephone receiver having sufficient impedance for the partlcular purpose 1n view, for instance, 100 to 2000 ohms resistance.

In Fig. 4 the electromotive force across the indicator circuit from the auxiliary terminal to the main negative electrode is more or less counter-balanced, or if desired, overbalanced by the potentiometer 18 shown. The latter may be adjusted to cause slight current fiow to or from the auxiliary electrode, and this device may be usedin connec 1OI1 with the other devices and circuits shown herein.

ig. 6 shows a form of device wherein there may be special heatingaction of the positive electrode 11" on the negative electrode when the positive electrode is so designed with respect to the current flowing therethrough as to be highly heated. To

this end the positive electrode is made small,

so as to become heated by the passage of current from it, and is concentrically arranged around a projection 12 from the negative electrode, which it tends to heat,

this projection tending to render stable the negative electrode reactions at its base. Such a positive elect-rode being constructed of platinum wire .057 inches in diameter and Wound in a helix, having an inside diameter of 1/4 inch and being of two turns, will become heated with 1 ampere passing, and will work with 1-1/2 amperes, the bottom of the helix being-substantially 1/8 inch from the level of the mercury.

In Fig. 5 the vapor device is shown with connections to a receiving circuit which may be useful with other forms of the device. The receiving conductor S is shown tuned as at 47 to a quarter wave length and the lateral conductor 45 leading to the electrode 13 of the vapor device is also tuned as at 46 to the same frequency. The ground connection G may be adjustably connected to v the coil 46, 47, 46, as at 48, and when such ground is used the circuit G, 48, 47, S will be the electrical equivalent of the circuit G, 48, 46, 45, 13, so that there will be a crest ofpotential at 13. 7

In Fig. 7 the vapor device issliown as connected through a lateral conductor 54 with a closed tuned or resonant circuit, prefe crably tuned to the frequency of the received energy to be detected by means of'a su tableadjustable inductance 51 and an adjust-able condenser 52. This closed tuned circuit is associated by means of a transformer 53 with a receiving wire S, and the parts may be, all designed and operated in accordance with any of the principles well known in the art. The lateral conductor is shown adjusted as at 55 tothe quarter Wave length of the received energy so that there will be a resonant rise of potential at C Referring more particularlyto the arrangement of Fig. 5, if the auxiliary electrode 13 be a circular plate 1-1/4 inches in diameter and its distance from the mercury negative electrode 2 be five inches and the main positive electrode be a ring of iron 1-1/8 inches outside diameter having a hole in the centerl/4 to 5/16 inch in diameter and if it be situated 3/8 of an inch from the surface of the mercury electrode, the container vessel being substantially from 2-1/2 to 3 inches in diameter, and properly exhausted, said vapor device will respond to extremely faint variations. Its sensitiveness may be increased by approaching an ordinary permanent magnet M somewhat in the manner shown in Fig. 7, the distance varying from close proximity to the device to 18 inches or so from it.

A second magnet applied as shown in Fig. 7 may have a beneficial effect in tending to produce a resultant magnetic field wherein the lines of force lying in the path above 11 and 12 are at an angle of approximately 45 degrees from the normal vertical position of the negative electrode flame.

' The various conditions of electrode size and location, main current flow, etc., may be so adjusted by trial as to cause a whistling sound or a regular note in the telephone when the magnet is at a suitable distance from the container; By then adjusting one of the variables, preferably the magnet, the device may be put in a critical Orr-unstable condition, where faint signals may be indicated by perceptible changes inthe quality, pitch, or intensity of such sound. In some cases the device may be put in a con dition where there is little orno perceptible note audible and yet the balance is so delicate that the faintest disturbance, will precipitate the sound of the note, thus giving a.

strong signal where otherwise the effect might be nearly or quite inaudible.

The circular auxiliary electrode 13 is shown in Fig.' 5 as flattened and arranged in a transverse plane with the flat surface approximately equidistant from the path betwecnthe main electrodes, so that almost all of the surface of the electrode exposed to the vapor lies in an approximately equipotential region of suitable current density.

This arrangement has certain advantages where it is desired to use a fine adjustment of counter electromotive force of a potentiometer to secure the most sensitive condition for feeble signals. One reason for this is that if the auxiliary-electrode is formed or arranged so that the exposed surface thereof extends through regions at materially diflerent distances from the path between the main electrodes, different parts of such exposed surface may lie in regions of materially. different current density. While this latter condition may not be objectionable for many purposes, it is sometimes found to be unsatisfactory for the finest work in connection with the faintest signals.

I One probable reason for this is that the condition of most extreme sensitiveness of the auxiliary electrode seems to depend upon getting an extremely fine balance of the counter electromotive force -of the potentiometer against the electrical pressure at the surface of the auxiliary electrode. The latter pressure has for one important determining factor the current density in j the portion of the vapor in contact with the electrode, and it seems to be a fact that if the auxiliary electrode is so formed or arranged that there are materially different current densities in the vapor adjacent different portions of its surface, the counter electromotive force of the potentiometer when set. to a vproper value for the current density adjacent one portion of the exposed surface, will be either too great or too small for other portions where the adjacent cur: rent density is of different value. On the other hand, if all portions of the exposed electrode surface are acted upon by vapor v,or substantially the same current density,

the counter eletromotive force may be very accurately adjusted to that current density, and such adjustment being perfect for one portion of the electrode is perfect fo any other portion of the electrode.

Another reason may be that a uniform density or current flow into and out of a considerable area of the electrode may be dem'rable This result should be accomplished by the above arrangement of the auxiliary electrode, because by it the lengths and resistance ofthe vapor path from different portions of the surface of the electrode, will be substantially equal.

My experiments show that other things being equal, the perforated plate or ring positive electrode of Fig. 7 seems to give smoother efiects more directly proportional to the received variations, whereas an imperforated disk seems to give more distorted or disproportionally amplified indications. This quality of the disk-or imperforate plate seems to preserve the value of the amplified variations more accurately cation or asymmetric translation of variations of an extremely small fraction of a volt andof the h ghest frequency, thereby rendering possible the use of a direct current indicating instrument.

I have found it desirable in order to fully utilize the asymmetric resistance characteristics of the device to so arrange the auxiliary electrode that it will act as-anapproximately no resistance pdsitive electrode and as a substantially prohibitive negative electrode with respect tooscillations of the strength which it is desired to translate or detect by such device.

This result may be achieved in connection with any of the typical circuits and devices shown herein. Referring for convenience to Fig}. 5, the electrode 13 should be located at such distance from the main electrodes ll, 12 that the current flow therefrom and the current density of the vapor adjacent thereto isnear the point where normal internal variations begin to cause disturbing indications in theinstrument R. In a particular case this distance might be somewhere be tween 4 and 7 inches or, say, about 5 inches. The distance should be and in the case mentioned usually will be, such that the current density in the vapor adjacent the auxiliary electrode will not be su fiicient to neutralize the opposition or reluctance of such elec trode to act as a negative electrode with respect to impulses of the strength which it is or less. If now the'potentiometer 18 be applied as a source of counter electromotive force, this drop may be counterbalanced by adjusting the potentiometer to a pressure of, say, /10 voltin the opposite direction. It is a peculiarity of such device,- however, that in order to suppress the efiects .of internally originated disturbances in the telephone R, the counter electromotive force should be slightly greater than the original drop, or say somewhere a'bout 75/100 volt, Where the drop was found to be 7/10 volt. By still further experimental refinement of adjustment of this counter electromotive force, the voltage, drop at the auxiliary electrode may be reduced practically to a zero, so that half Waves or impulses of the smallest fraction of a volt, say, for instance, 1/10 volt to 1/100 volt, or less, will pass freely and practically unimpeded into the vapor, whereas the half waves or impulses tending to run in the opposite direction will be blocked and prevented from passing from the .gas into the electrode 13, so that the effects of the variations are observable in a direct current instrument. The adjustable potentiometer thus arranged, is an accurate means for attaining at the electrode 13, the

conditions which will best serve the purpose of detecting alternating currents by a direct current instrument and yet not give rise to undue internally originated disturbances which miglilt tend to mask the effects in the indicator While I have last above described an arrangement of my device which is particularly efiicient for rectifying, it will be understood that the device is so remarkably sensitive in such a variety of ways that, it will act as a very good detector of feeble variations such as are characteristic'of'the receiving wires of ordinary commercial Wireless telegraph systems, even when the ad j ustments are such that the asymmetric action is at a minimum. 7

With reference to magnets, it will be understood that the position and number of the magnetic lines and their action with respect to the negative electrode flame and other phenomena, may be varied as desired,

to suit the conditions.

I claim:

1. An apparatus for translating electrical variations comprising a translating device and a connection therefrom through an electrode to a body of conducting gas or vapor, adapted to be maintained in a low resistance conducting condition in combination with means for continuously maintain:

a ing current in said vapor independently of said electrode, and a conducting band for electrostatically applying variations to said apparatus, substantially as described. I

2. An apparatus for translating electrical variations comprising a translating device and a connection therefrom through a true conductor of the first class to. a conducting gas or vapor maintained in-the low resistance conducting condition in combination with means for continuouslymaintaining current'in the gasor vapor independentlyof Said connection through said true conductor, and a conducting band for electrostatically applying variations to said apparatus, substantially as described.

normal current flow therein, the positive electrode extending into the dark space adjacent to the negative electrode, together with an encircling band variably charged through said variation connection.

5. An apparatus for translating electrical variations. comprising indicator, variation and main current supply connections, in combination with a gas or vapor: tube provided with electrodes for maintaining normal current flow therein, the positive electrode extending into the dark space adjacent to the negative electrode, and one of them being of vaporizable material, together with an encircling band variably charged through said variation connection.

6. An apparatus for translating electrical variations comprising indicator, variation and main current supply connections, in combination with a gas or vapor tube, provided with electrodes for maintaining normal current flow therein, the positive electrode extending into the dark space adja cent to the negative electrode, the negative electrode being of vaporizable material and encircling band variably charged through said variation {connection 7. An apparatus for translating electrical variations, comprising an evacuated container, cooperatingelectrodes, circuit connections therefor, and an indicator, operatively associated therewith, in combination with a capacity area consisting of an encircling band in inductive relation to said container, and a source of electrical variations connected to said capacity area, for the purpose described.

8. An apparatus for detecting feeble electrical variations comprising a hermetically sealed container having a high vacuum when cold and. provided with main elec trodes, an auxiliary terminal, and a circuit therefrom through an indicator, in combinasealed container having a high vacuum when sisting of an encircling band in inductive relation to said container, and a main circuit for maintaining current flow through said main electrodes of suflicient quantity to maintain the main negative electrode in the broken down state, substantially as described.

10. An apparatus for detecting feeble electrical variations comprising a hermetically cold and provided With main electrodes, an auxiliary terminal, and a circuit therefrom through an indicator, in combination With a capacity area consisting of a band mounted upon said container, adjacent said auxiliary electrode, and a main circuit for maintaining current flow through said main eleotrodes independently of said auxiliary terminal.

11. The method of utilizing the reactions at an electrode in a gas or vapor device supplied with currents independently of said electrode, which method consists in correlating the location of the exposed surface of the electrode and the distribution of the independently supplied current so as to present an approximately prohibitive negative electrode resistance to passage of current from the vapor into said third elecmeaaei s. tr de and an approximately minimum re- 51 tfance to passage of currents 1n the op- ,gposlte direction, and applying electrical vapassage of current from the vapor into said third electrode andan approximately minimum resistance to passage of currents in the opposite direction, and applying electrical variations by electrostatic induction in the region of said electrode and the adjacent vapor, substantially as described.

13. The method of utilizing the reactions at an electrode in a vacuum device containing a monatomic gas or vapor suppliedwith currents independently of said electrode, which method consists in correlating the location of the exposed surface of the electrode and the distribution of the independently supplied current so as to have its re-. actions at or near the point Where its opposition to the passage of negative current approaches a maximum, and applying electrical variations by electrostatic induction in the region of said electrode and the ad jacent vapor, substantially as described.

Signed at New York city, in the county of New York and State of New York, this 14th day of May, 1915.

PETER COOPER HEWITT. Witnesses:

' WALTER E. F. BRADLEY, RAYNER M. BEDELL.

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