US586193A

US586193A - transmitting electrical signals

Info

Publication number: US586193A
Authority: US
Publication date: 1897-07-13
Anticipated expiration: 1914-07-13

Description

3 sheetsshea 2.

(No Model.)

G. MARCONI.' TRANSMITTING ELECTRICAL SIGNALS.

No. 586,193. Patented July 13, 1897.'

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Zik/ama (No Model.) 3 Sheets- Sheet 8.

Gr. M A R C 0 NI.

TBANSMITTING ELECTRICAL SIGNALS. 110.586,19). Patented July 13, 1897.

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. lS-l Wsses Invenr UNITEDv STATES PATENT OFFICE.

GUGLIELMO MARCONI, or I. ONDON, NGLAND. f

TRANSMITTING ELECTRICAL SIGNALS.l 'v

SPECIFICATION forming* part of Letters Patent No. 586,193, dated July 13, 1897.

Application filed December 7, 1896. Serial No. 614.838. (No model.)

Zi) (all whom it may concern:

Bc it known that I, GUoLIELMo MARCONI, student, a subject of the King of Italy, residing at 2l Burlington Road, London, in the county ot' Middlesex, England, have invented certain new and useful Improvements in 'lransmitting Electrical lmpulsesian d Signals and in Apparatus Therefor, of which the` following is a specification.

According to this invention electrical signals, actions, or manifestations are transmitted through theair, earth, or water by means 'pensed with.

of oscillations of high frequency, such as have been called the llertz rays7 or Hertz .oscillations. Usually all line-wires are dis- At the transmitting-station I employ a Ruhmkorif coil, having in its primary circuit a Morse key Or other signaling instrument andiat its poles appliances for producing the desired oscillations. f The Ruhm-l kor coil may, however, be replaced by any other source of high tension electricity. wWhen Working with large amounts of energy, it is, however, better to keep the coil or transformer constantly Working for the time .during which one is transmitting, and instead of interrupting the current of the primary interrupting the discharge of the secondary. Inthis case the contacts of the key should be immersed in'oil, as otherwise, owing to the length of the spark, the current Willcoutinue to pass after the 'contacts have been separated. At the receiving-'station lthere isI a local-battery circuit, containing any ordinary receiving instrument and an appliance for closing the circuit, the latter being actuated by the oscillations from the transmitting-station.` When transmitting throughA the air and it is desired that the signal should only be sent in one direction, I place the oscillation-producer at the transmitting-station in thc focus or focal line of a reiiector directed to the receiving-station, and I place thecircuit-closer at the receiving-station in a simi-` lav.` reflector directed toward the transmittingstation. f When transmitting signals through the earth, I connect one end of they oscillation-producer and one end ofv the circuit-k closer to earth and theaother ends to similar plates, preferably elcctrically'tuned with each other inthe air and insulated from earth.

Figure 1 is a diagrammatic front elevation of the instruments at the transmitting-station when signaling through the air, Aand Fig. 2 is a vertical section of the transmitter. Fig. 2 is a longitudinal section of the oscillator to a larger scale. Fig. 3 shows a 'detail on a larger scale. Fig. 4 is a diagrammatic `front elevation of the instruments at the receivingstation. Fig. 5 is a full-sized view of the receiver. Fig. 6 shows a modification of the tubej. Fig. 7 shows the detector. a full-sized View of the liquid-resistance. Figs. 9 and lO show modifications of the arrangements at the transmitting-station. Fig. lIl shows a modification of the arrangements at the receiving-station.

Referring now to Fig. l, ois a battery, and b an ordinary Morse key closing the circuit through the primary of a ltuhmkorll' coil c. The terminals c of the secondary circuit of the coil are connected to two metallic balls d d, fixed by heat or Otherwise at the ends of tubes (ZV, d', Fig. 2, of insulating material, such as ebonite or vulcanite. c e are similar balls fixed in'the other ends of the tubes d. The tubes d iit tightly in a similar tube d2, having covers d3, through which pass rods di, connecting the balls d to the conductors. One (or both) of the vrods d4 is connected to the ball d by a ball-and-socket joint and has a screw-thread upon it working in a nut iu the cover d3. By turning the rod therefore the distance of the balls c apart can be adjusted. d5 are holes in the tube (Z2, through Which vascline,'oil, or like material is introduced into the space between the balls e rig. c is The balls d and c are preferably of solid l brass or copper, and the distance they should be apart depends on the quantity and electromotive force of the electricity employed, the effect increasing With the distance so long as the discharge passes freely. With a coil giving an ordinary eight-inch spark the distance between c and c should be from one twenty-fifth to One-thirtieth of an inch and the distance between d and e about one and a half inches. fis a cylindrical parabolic reflector vmade by bending a metallic sheet,

`preferably ofV brass or copper, to form and ixing it to metallic or wooden ribs f. Other conditions being equal the larger the balls the greateris the distance at W'hich it is possible to communicate. rI have generally used s scales I balls of solid brass of four inches diameter, giving oscillations of ten inches length of wave. y

The reflectors applied to the receiver and transmitter ought to be preferably in length and opening the double at least of the length of wave emitted from the oscillator. o.

If a very powerful source of electricity giving a very long spark be employed, it is preferable to divide thespark gap between the central balls of the oscillator into several smaller gaps in series. This may be done by introducing between the big balls smaller ones, (of about half an inch diameter,) hel in position by ebonite frames.

I find that the regularity and power of the discharge of an ordinary Ruhmkori coil with a trembler-break on itsprimary. is greatly improved by causing one of the contacts of the vibrating break to revolve rapidly. I do this by having a revolnble central' core 02, Fig. 3, in the ordinary screw c?, which is in communication with the platinum contacts. I cause the said central core with one of the platinum contacts attached toit to revolve by connecting itV to a small electric motor c4. This motor can be worked by the same circuit that worksthe coil, or,` if necessary, by a separate circuit. The connectionsare not shown in the drawings. By this means the platinums are kept smooth and any tendency to stick is removed. They last also much longer. At the receiving-station is a battery whose circuit includes an ordinary telegraphic instrument (or it may be a relay or other apparatus which it is desired to work from a distance) and a circuit-closer.

In Fig. 4, g'is the battery, and h a telegraphicinstrument on the derived circuit of' a relay n. i

The appliance I employ as a circuit-closer is shown full size at Fig. 5 and consist-sof a glass tube g', containing metallic powder or grains of metal j', each end of the column of powder being connected to a metallic plate k of suitable length to cause the system to reso,- nate electrically in unison with the electrical oscillations transmitted. The glass tube may be replaced in some cases by'one of guttapercha or like material. Two shortpieces of thick silver wirej2 of the same diameter as the internal diameter of the Itubej, so `as to .fit tightly in it, are joined to two pieces of platinum wire ja.' The `tube is closed `and sealedonto the platinum wiresjs at both ends.

Many metals can be employed for producing the powder or filings j; but I pre'fer to use a mixture of two or-'more diierent metals.

I find hard nickel tobe ,the best metal, and I pre-fer to add to the nickel filings about t-en per cent. of hard-silver lin gs, which Aincrease greatly the sensitiveness of the tube to electricoscillations. By increasing the proport-1on of silver powder or grains the sensitiveness of the tube also increases; but it is bet ter for ordinary work not to have a tube of too great sensit-iveness, as it might be indu-- 'tity as to clot or cake the lings.

the filings and mixing up untiltheme'rcury is absorbed.

The mercury must not be in such la'quan- An almost imperceptible globule is suiicient for a tube. Instead of mixing the mercury withthe powder one can obtain the same effects by slightly yamalgamating the inner surfaces of the plugs which are to be in contact with the filings. Yery little mercury must be used, just sutilcient to brighten the surface of the metallic plugs without showing anyffree globules. The

size of the tube and the distance between the two metallic stops may-vary under certain following size: The tube 7' is one and one-half inches long and one-tenth or one-twelfth oi' an inch internal diameter. The length of the stops b7'2 is about one-fifth of an inch, and the distance between the stops is about one-thirtieth of an inch. I nd that the smaller the space between the stops in the tube the more sensitive it proves, but the space cannot under ordinary circumstances be excessively shortened withoutinjuringthe vfidelity of the transmission.

The metallic powders ought not to be fine, but rather as coarse as can be produced by a large and rough file.

All the very ne powder ought to be removedl by blowing r sifting.

The powder ought not to be compressed be-` tween the stops, but rather loose and in such a condition that when the tube is tapped the powder may be seen to move;

The tube must be sealed, but a vacuum inside it is not essential, except the slight vacuum which results from having heated it while sealingit. Care must alsobe taken not to heat the tube too much inthe center when sealing it, as it would oxidize the surfaces of the silf ver stops and also the powder, which would diminish its sensitiveness. I usev in sealing the tubes a hydrogen and air flame. A vacn'nm is, however, desirable, and I have .used one of about one-one-thousandth of an atmosphere, obtained bya mercury-pump. It is also IOS necessary for the powder or-grains to be dry and free from grease or dirt, and the files used in producing the same ought to be frequently I washed and dried and used when warm.

If the tube has been well made, it should be sensitive to the induction of an ordinary elecmilliampere to flow through itwhen active.

If a stronger'current is necessary, several tubes maybe put in derivation between the c quite as satisfactory as the single tube.

tuned plates, but this arrangement is not It is necessary when using tubes ofthe type I have described not to insert in the circuit more than one cell of theLeclanch type, as a higher electromotive force than 1.5 volts is apt to pass `a current through the tube even when no oscillations are transmitted. I can, however, construct tubes capable of working with y there are several spaces-separated by sections of ti gilt-fitting silver wire. A tube thus constructed, observingclalso the rulesof construc-v tion of my tubes in general, willwork satisfactorily if the electromotiveforce of the battery in circuit with the tube is equal to 1.2

' yolts in nltiplied by the number of gaps. With this tube also it is well not to allow a current of more than one milliampere to pass.

' The tube j may be replaced by other forms of imperfect electrical contacts,'but this is not desirable. i

rllhe plates'c are of copper or aluminium or other metal, about half an inch or more' broad,

. about one-iiftieth of an inch thick, and preferably of such a length as to be electrically tuned with the electricoscillat-ions transmitted. The meansl I adopt for fixing the length of the plates is as follows: I stick a rectangular strip of tinsfoil m (see Fig. 7) about twenty inches long (the length depends on` the supposed length of'wave that one is measuring) bymeans of a weak solution of gum ontof a glass plate m. Then by means of avery sharp lpenknife or point I cut across the middle of the tin-foil, leaving a mark of division If this detector is heldin the proximity (four or live yards) and parallelwith the axis of the oscillator in action, it will show little sparks at m2. It' the length of the pieces of tin-foil approximatesto the length of wave emitted from the oscillator, the spark will take place rbetween them at a certain distance from the transmitter, which is a maximum when they are of suitable length. By shortening or lengthening the strips, therefore, it is easy to find the length most appropriate to the length of wave emitted by the oscillator. It is desirable to try this detector in the focus or focal line of the reflector. The length so found is the proper length for'the plates k, or rather these should be about half an inch shorter'on account of the .length oi' the sensitive tube .7',

' connected between them.

Z is a cylindrical parabolic reflector similar to that used at the transmitting-station.

'lhe plates la may be in the form of tubes or even wires. y

It is slightly advantageous for the focal distance of the reflector to' be equal to one-fourth .or--threefourths of the wave length of the 0s- :transmitting-station, the 'tube j does not conduct the currentfand the local-battery circuit p is broken, but when the powder or tube is influenced by the electrical oscillations from the transmitter it conducts and closes the circuit. I ind, however, that when once lstarted the powder in the tube continues to conduct even when the oscillations from the transmitter have ceased, but if it be shaken ;or tapped the circuit is broken. A tube well prepared will instantly interrupt the current passing through it at the slightest tap, provided it is inserted in a circuit in which there is little self-induction and small electrombtiv'e force, such as a single cell, and where `the effects of self-induction have been removed by one of the methods which I will presently describe.

The two plates 7o communicate with the lo cal circuit through two very small coils k',

which I will call choking-coils, formed by winding a few inches 'ofvery thin and insulated copper wire around a bit of iron wire about an inch and a half long. The object of these chohin g-coi-ls is to prevent the high-frequency oscillation induced across these plates bythe transmitter from dissipating itself by running along the local battery wires which might weaken its effect on the sensitivetube j. These choking-coils may,however,be sometimes Areplaced. bysimple thin wires. They may also be connecteddirectly to the tube j. 'The local circuit in which the sensitive tube j is inserted contains a sensitive relay n, prefs erably wound to a resistance of about twelve hundred ohms. This resistance need not be necessarily that ofthe relaybut may be the sum of the resistance of the relay and another additional resistance. The relay ought to be one possessing small self-induction- The plates k, tube j, and coils lo are fastened by means of wire stitches o to a thin glass tube o, preferably not longer than twelve inches, firmly fixed at one end to a strong piece of timber o2. .This may be done by means of lwood or ebonite grasping-screws.

I do the tapping automaticallyby the current started by the tube, employing a trembler 10 on the circuit of the relay fn similar in construction to that of an electric bell, but havling a shorter arm. The Avibrator must be carefully adjusted. Preferably the blows shouldbe directed slightly upward to prevent In place of the filings from getting caked. tapping the tube the powder can be disturbed by slightly moving outward and inward one or bothY of the stops ,7"2, the trembler p being replaced by a-small electromagnet (or magnets) whose armature is connected to the stop.

I ordinarily work the telegraphic receiver h (or other instruments) by a derivation, as shown, from the circuit which works thc trembler p. Theyl can also, however, be worked in series with the trembler. "When working ordinary sounders or Morse apparatus, a special adjustment of thc same is sometimes needed to enable one to obtain dots and dashes. Sometimes it is necessary to work the telegraphic instruments or relays from the back-stops of the first relay, as is done in IIC;

' some systems of multiple telegraphy. ,Such

adjustments are known to telegraphic experts.

Bymeans of a tube with multiple gaps it is 'possible to work the trembler and also the` signaling or other apparatus direct onA the eircuit which contains the tube, but I prefer -when possible towork `with the single-gap tube and the relay, as shown. With a sensitive and well-constructed trembler it is also `'possible to work the trembler' with the singlegap tube in series with it without the relay. In derivation on the terminals of the relay 'n is placed an ordinary platinoid resistance double-wound' (or wound on the bight, as it is -.sometimes termed) coil q of aboutl four times'the resistance of the relay, which prevents the self-induction of the windingof the relay from aeetin g the sensitive tube.

The circuit actuated by the relay contains an ordinary "battery q" of 'about twelve cells ratus, if on a derivation, lshould have a resistanceequal to the resistance of the trem- .bler p. A platinoid resistance h of abeht ive times the resistance of the instrumet is inserted in .derivation across the terminals of the Ainstrument and connected as close to the same as possible. In derivation a ross .-,lthe

terminals of the trembler pis placed another.v

platinoid resistance also of about five times* the resista-nce of the trembler. 'A similar re- `sistanee p2 is inserted'in a circuit connecting -the vibrating contacts of., the trembler!y In derivation across the terminals of the relaycircuit it is well to have a liquid resist-ance s, which is constituted of a series of tubes, 'one of which is shown full size in Fig. 8, filled with Water acidulated with sulfuric acid. I /The l number othese tubes in series across lthe said terminals ought to be about ten for a circuit of fifteen volts, so as to prevent, in con-. sequence of their counter electromotive force,

= the current of the local battery fro'mpassing through them, but allowing the high-tension jerk of current generated at the opening of the circuit in the relay to pass smoothly across them without producing perturbing sparks at' the 'movable contact of the relay. It is also necessary to insert a platinoid resistance in derivation'on .any apparatus one may be working on the local circuits. These resistanes ought also to be insertedin derivation on the terminals of any resistance which may l be apt to give self-induction.

I have hitherto only mentioned the use of cylindrical reflectors, but it is also `possible ,to use ordinary concavereilectors, preferably parabolic, such as are used for projectors.-

It is not essential to have a reflector at the transmitters and receivers, but in their absence the distance at which one can communicate is much smaller. y 'I iind it convenient when transmitting across longdistances to make mitter shown in Fig. 9. Y X. t t are two poles connected by a rope t', to which are suspended by means of insulating Suspenders two-metallic plates i? t2, preferably in the form of cylinders closed at the top, connected to the spheres e (inoil'or other dielectric, as before) and to the other balls t3 in proximgity to the spheres c', in com mu nicationwith the coil or transformer c., The balls t3 are not 'absolutely necessary, as the plates t2 may be -made to communicate with the coil or transformer by means of thin insulated wires. The receiver I adopt with this transmit-ter is simiuse of the trans.l

lar Ato it, except that the spheres ev are replaced by the sensitive tube j and plates 7.', while the spheres t3 are replaced by the choking-coils k', in communieationwith the loc`al circuit. It may be observed that, other conditions being equal, the larger the plates at the transmitter and receiver and the higher 4 they are from earth and .to a ccrtainextent the farther 'apart they are the greater is the distance at which correspondence is possible.

When transmitting through the earth or water, I use a transmitter as shown in Fig. 10. lI connect one of the spheres d to earth E, preferably lby a thick Wire, and the other lOO to a plate oreonduotor u, suspended on a pole 4 o and insulated from' earth; or the spheres (l ,may b e omitted and one of the. spheres e be connected to earth and the other tothe plate or conductora. At the receiving-stationl1`ig. 1 l, I connect one terminal of the sensitive tube ,j to earth E, also bya thick wire, and the other to a plate or conductor w, preferably similar to u. rIhe plate w may be lsuspended on a pele a: and must be insulated from earth. The largerv the plates of the receiver and transmitter and the higher from the earth the plates are suspended the greater is the distance at which it is possible -to'communicate When' using, the last-described apparatus, it is not necessary to have the two instruments in view of each other, as it -is of no consequence if they are separated by mountains or other obstacles; At the receiver it is possible to pick up the oscillations vfrom. the earth or water without having the plate w. This may be done by connecting .the terminals of the sensitive'tube j to two earths, preferably at a certain distance from each, other and in a line with the direction'from which the oscillations .are coming. These connections must not be entirely conductive, but must contain a condenser of suitable capacity-say one square yardof,surface.` Balloons can also be used instead of plates on poles, provided they carry upa plate or are themselves made conductive by being coveredwith tin-foil. Asthe height to which they may be sent is great,l the distance at which communication is possible be- IIO lio

comes greatly multiplied. Kites may also be successfully employed if made conductive by means of tin-foil.

The apparatus above described is so sensitive that it is essential either that the transmitters and receivers at each station should be at a considerable distance from eachother or that they should be screened from each other by stout metal plates. It is sufficient to have all the' telegraphic apparatus in a metal box and any exposed part of the circuit of the receiver inclosed in metallic tubes which are in electricalA communication with the box. (Of course the part of the apparatus which has to receive the radiation from the distant station must not be inclosed, but possibly screened from the local transmitter by means `of metallic sheets.) Vhen working through the earth or water, the local receiver must be switched out of circuit when the transmitter is at work, and this may also be tact, choking-coils connected to the contact,`

a circuit through the coils, and contact and means actuated by the circuit for'shaking the contact.

4. In a receiver for electrical oscillations the combination of a tube containing metallic powder, a circuit through the powder and means actuated by the circuit for shaking the powder.

5. In a receiver for electrical oscillations the combination of a tube containing metallic owder, metallic plates connected to the powger, a circuit through the powder and means actuated .by the circuit for shaking the powder. c l

6. In a receiver for electrical oscillations the combination of a tube containing metallic powder, metallic plates connected to the powder, choking-coils connected to the powder, a circuit through the coils and powder and means actuated by the circuit for shaking the powder.

7.- lu a receiver for electrical oscillations the combination of a tube containing a mixture of metallic powders, a circuit through the powder, and means actuated by the circuit for shaking the powder.

S. In a receiver for electrical oscillations the combination of a tube containing a mixture of metallic powders, metallic plates connected to the powder, a circuit through the powder and means actuated by the circuit for shaking the powder. V

9. In a-reeeiver for electrical oscillations the combination of a tube containing a mixnectcd to thel powder, choking coils connected to the powder, a circuit through the coils, and powder and means actuated by the circuit'for shaking the powder.

l0. In a receiver for electrical oscillations the combination of a tube containing a mixture of metallic powder and mercury, a circuit through the powder and means actuated bythe circuit for shaking the powder.

11. In a receiver for electrical oscillations theV combination of a tube containing a mixtureof metallic powder and meren r f, metallic plates .connected to the. powder, a .circuit through the powder and means actuated by.

means actuated by thc circuit for shaking the powder.

14. In a receiver for electrical oscillations the combination of a tube, metallic plugs in 'the tube,'metallic powder between the plugs,

metallic plates connected to them, a circuit through the plugs and powder .and means actuated by the circuit for shaking the powder.

15. In a receiver for electrical oscillations the combination of a tube,metal'lic plugs in the tube, metallic powder between the plugs, metallic plates connected to the plugs, clickingcoils connected to they plu gs, a circuit through the coils and plugs and means actuated by the circuit'forgshaking the powder.

16. ,In a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture.ofjmetallic powders between the plugs, a-"circuit through the plugs and powder and mea cuit for shaking the powder.

17. In a receiver'fo'r-electrical oscillations the combination of a tube, metallic plugs inV ,s actuated by the cir`- `ture of metallic powders,`metallic plates con- IOO 18. In a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of .metallic powders between tlic plugs, metallic plates connected to the plugs, choking-coils connected to the plugs, a'circ'uit through the coils plugs and powder and means actuated by the circuit for shaking/the powder. l Y

19. In a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic powder and mercury between the plugs, a circuit through the plugs and powder and means actuated by the circuit for shaking the powder.

20. In a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic powder and mercury between the plugs, metallicv plates connected to the plugs, acircuit through the plugs and powder and means actuated by the circuit for shaking the powder.

2l. 4In a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic powder and mercury between the plugs, metallic plates connected to the plugs, choking-coils connected to the plugs, a circuit through the coils plugs and powder and means actuated bythe circuit for shaking the powdeny 22. In a receiver for electrical oscillations the combination of an imperfect velectrical contact, a circuit through thecontact, a relay actuated by lthe circuit and means actuated by the relay for shaking the contact,

f 23. In a receiver for electrical oscillations the combination of an imperfect electrical contact, metallic plates connected to it, a circuit through the contact, a relayactuated by the circuit and means actuated bythe relay for shaking the cont-act.

24. In a receiver for electrical oscillations the combination of an imperfect electrical,

contact, metallic plates connected to the contact, choking-coils connected to the contact, -a circuit through the coils and contact, a relay actuated by the circuit and means actuated bythe relay for shaking the contact.

- 25. In a'receiver for electrical oscillations the combination of a tube containing metallic powder, a circuit through the powder, a

relay actuated by the circuit and. means ac-4 tuated by the relay for shaking the powder. 26. In a receiver for electrical oscillations the combination of a tube containing metallic powder, metallic plates connected to thel powder, a circuit through the powder, a relay actuated bythe circui-tand means actuated by the relay for shaking .the powder. .i

27. In a receiver for electrical oscillations the combination of a tuber containing metallic powder, metallic plates connected to the powder, choking-coils connected to the powder a circuit through the coils and powder a relay actuated by the circuit and means actuated by the relay for shaking the powder.

28. In a receiver for electrical oscillations the combination of atube containing a mixture of metallic powders, a circuit through .the powder, a relay actuated by the circuit and means actuated by the relay for shaking 'the powder.

29. In a receiver for electricalfoscillations the combination of a tube containing a mixe ture of metallic powders, metallic plates connected to the powder, a circuit through the powder, a relay actuated by the circuit and means actuated by powder. y

30. Inra receiver for electrical oscillations the combination of a tube containing a mix ture ofmetallic powders, metallic plates connected to the'powder, choking-coilsconnected to the powder, a circuit through the coils and powder, a relay actuated by the circuit and means actuated by the relay for shaking the powder. p

3l. In a receiver for electrical oscillations the combination of a tube containing a mixthe relay for shaking the s ture of metallic powder and mercury, a circuit through the powder, a relay actuated by thefcircuit and means actuated by the relay for shaking the powder.

' 32. In a receiver for electrical oscillations the combination of al tube containing a mixture of metallic powder and mercury, metallic plates connected to thepowder, a circuit through the powder, a relay actuated by the circuit and means actuated bythe relay for shaking the powder.

y 33. In a receiver for electrical oscillations the combination of a tube containing a mixture of metallic powder and mercury, metallicV plates connected to the powder, choking-coils connected to the powder, a circuit through the coils vand powder, a relay actuated bythe circuit and means actuated by the relay for shaking the powder.

34. In a receiver for electrical oscillations the combination of a tube, metallic plugs-in the tube, metallic powder betweeny the plugs, a. circuit through-the plugs and powder, a re- `lay actuated .by the circuit and means actu- -ated yby the relay for shaking the powder.

85. In a receiver for electrical oscillations thecombination of a tube, metallic plugs in the tube, metallic powder between the plugs, metallic plates connected to the plugs, a circuit through the, plugs and powder, a relay actuated by the circuit and means actuated by the'relay for shaking the powder.

36. In a receiver for electrical oscillationsl the combination of a tube, metallic plugs in the tube, metalliclpowder between the plugs, metallic plates connected to the plugs, choking-coils connected to thel plugs, a 'circuit through the coils, plugs and powder, a relay actuated by the circuit, and means actuated by the relay for shaking the powder.

37. In a receiver for electrical oscillations the combination of a-tu'be, metallic plugs in the tube, a mixture of metallic powders between the plugs, a circuit through the plugs and powder, a relay actuated by the circuit, and means actuated by the relay for/shaking the powder.

38. In a receiver -for electrical oscillations.

tween the plugs, metallic plates connected to loo' ' the plugs,a circuit through the plugs and' powder, a vrelay actuated bythe circuit, and means actuated by the relay for shaking the powder.

39. In a `receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic `powders between the plugs, metallic plates connected to the plugs, choking coils connected to the plugs, a circuit through the coils, plugs vand powder, a relay actuated by the circuit and means actuated by the relay for shaking the powder.`

40. In a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic powder and mercury between the plugs, a circuit through the plugs and powder, a relay-'actuated by the circuit and means actuated by the relay for shaking the powder.

4l. ln a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic powder and mercury between the plugs, metallic plates connected to the plugs, a circuit through the plugs and powder, anelay actuated by the circuit and means actuated bythe relay for shaking the powder.

42. In a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic powder and mercury between the plugs, metallic plates connected to the plugs, choking-coils connected to the plugs, a circuit through the coils,

plugs and powder, a relay actuated by the circ uit and means actuated by the relay for shak.

ing the powder.

48. The combination ot a spark-producer at the transmitting-station, an earth connection to one end of the spark-producer, an insulated conductor connected to the other end, an imperfect electrical con'tact at the receiving-station, an earth connection to one end of the contact an insulated conductor connected to the other end and a circuit through the contact.

44C. The combination lof aspark-producer at the transmitting-station, an earth cunnection to one end of the spark-producer, an insulated conductor connected to the other end, an imperfect electrical contact at the receiv in g-station, an earth connection to one end of the contact an insulated conductor connected to the other end, a circuit through the contact and means actuated by the circuit for shaking the contact.

The combination of a spark-producer at the transmitting-station, an earth Iconnec tion to oneend of the sparkLproducer, an insulated conductor connected to the other end, an imperfect electrical'contact at the receiving-station, choking-coils connected to each end of the contact, an earth connection to one end of the imperfect contact an insulated conductor connected to the other end and a circuit throughthecoils and contact.

4G. The combination of a sparkeproducer at the transmitting-station, an earth connection to one end of the spark-producer, an insulated cond uctor connectedto the other end, an imperfect electrical contact at the receiving-station, choking-coils connected to each end of the contact, an earth connection to one sulated conductor connected to the other'end, a tube containing metallic powder at the receiving-station, an earth connection to one end of the powder, an insulated conductor connected to the other end and a circuit through the powder. i f

48. The combination of a spark-producer tion to one end of the spark-producer, an insulated conductor connected to the other end, a tube containing metallic powder at the receiving-station, an earth connection to one end of the powder anA insulated conductor connected to the other end, a circuitthrough the'powder and means actuated by the circuit for shaking the powder. 49.' The combination of a sparkproducer at the transmittingstation, an earthconnection toone end of the spark-producer, an insulated conductor connected to the other end, a tube containing metallic powder at the ,receiving-station, choking-coils connected to each end of the powder, an earth connection to one end of the powder, anv insulated con'- ,ductor connected to the other end and a circuit through the' coils and powder.

v 50. The combination of a spark-producer at the transmitting-station, an earth connec tion to one end of the spark-producer, an insulated conductor connected to the other end, a tube containing metallic powder at-the receiving-statio n, choking-coils connected to each end of the powder, an earth connection to onei end of the powder,'an insulated conductorconnected to the other end, a circuit through the coils and powder and means action to one end of the spark-producer, an inat the transmitting-station, an earth connec- IOO tuated by the circuit for shaking the powder.

5l. The combination of aspark-producer at the transmitting-station, an earth connec! `tion to one end of the spark-producer, an insulated conductor connected to theother end, a tube containingmetallic powder at the receiving-station, choking-coils and earth connection through condensers connected to each end of the powder, a circuit through the coils and powder and means actuated by the circuit for shaking the powder'.

52. ln a receiver for electrical oscillations,

contact, a circuit through the contact, an electric trembler shaking the contact, and means for preventing the self-induction of the trembler from aiecting the contact.

the combination of an imperfect electrical..

,2 5 be given out bythe receiver.

53. -A receiver for electrical oscillatorykimpulses having a medium whose electrical resistance'is altered by the received electrical oscillations, a trembler or` shaker for acting upon the'variable-resistance medium to re` store itt'to its normal condition of -electrical resistance,` and means fol-controlling such trembler to cause it to act upon the variable-i resistance medium to restoreit to its normal' condition aftereach reception of such oscillatory impulses. i y y 54. 5A' receiver for electrical oscillatory impulses having a'medium whose electrical resistance is altered by the/received electrical oscillations, a trembler or shaker for acting upon the variable-resistance medium toeren store it to 'its .normal condition of electrical resistance, means controlling such trembler tocanse it to act upon the variable-resistance 26* medium to restore it 'toits normal/condition after veach receptionof such oscillatory im-- pulses, and means for rendering manifest said electrical oscillatory impulses consecuf tively received,wliereby defined signals may 55; The combination ofa transmittercapaffv trie oscillatory limpulses or rays, and a receiver responsive thereto having a variableresistance medium whose resistance is altered by such received oscillatory impulses, means controlled by the receivedoscillations for restoring such medium toits normal condition aft-er each reception of such oscillations, and means forrenderin g manifest the received oscillations, whereby signals sent from the transmitter maybe received upon the receiver.

' 56. The combination of a transmitter capable ofproducin g electrical oscillations or rays at thedwill of the operator, and a receiver located at a distance and having va conductor tuned to respond to such oscillations, a variable-resistance#medium, in circuit with the conductor, whose resistance is altered by the received oscillations, means controlled by the received oscillations for restoring the resistance medium;J to its normal condition after each reception of 4such oscillations, and means for rendering the received oscillations manifest. i

GUGLIELMO MARCONL WILFRED CORPMAEL,

i ble' of. producing at will of the operator lelec,-

v FRED C. HARIES. A