US325958A - moses - Google Patents

Description

2 sheen-sheet 1.

\ (No Model.)

o. A. M0858. INGANDESCENT ELECTRIC LAMP.

N5. 825,958. Patented sept. .8, 1885.

4 .5 m mw Ff .5

S14/uente@ N. I'EYERS. Phuwumngnphor. Vlamingen. 0,6.

2 ShBtS--Shegt' 2;

(No Model.)

o. An/10888 INGANDESGENT? BLBGTRIQLAMP.

Patented 881188,*1885;

qUNiTnD STATES y PATENT Ormea@ OTTO A. MOSES, OF NEW YORK, N. Y.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming .part of Letters Ptent No. 325,958, dated September 8,1885. v

1 Applicationled July 30, 1884. (No model.) i

To @ZZ whom it may concern.-

Be it known that I, OTTO A. Mosus, a citizen of the United States, residing in the city, county, and State of New York,have invented certain new and useful Improvements in Incandescent Electric Lamps, of which the following is a specification.

This invention relates to the class of electric lamps in which the conductingstrip, wire, or filament of carbon, hydrocarbon, or other suitable refractory substance is inclosed within a transparent airtight globe or chamber from which the air is exhausted and which may or may not be filled with a non-oxidizing gas or vapor.

The invention claimed in this application relates particularly to the form and construction of the filaments and tothe method of inserting the same within the inclosing chamber; but a complete description will be given of the entire lamp and ofthe process of manufacturing the saine, for the purpose of more fully setting forth the invention and its applica tion.

In the construction of inclosiiig globes or chambers forincandescentlights it is desirable that the globe itself should be so formed that it will not be liable to crack or break when unevenly heated by the current employed for rendering the filament incandescent; that it shall be of uniform thickness and offer aslittl'e opportunity as possible for the ,formation ot' rings or shadows by refraction, and that the entire process of shaping, exhausting, and sealing the globe or vacuunrchamber should be simple and effective.v For this purpose it is desirable that the several elementsV comprised in the lamp-namely, the globe, thel incandescing filament, its supporting-conductors, and the supporting-cup-in connection with which the completed lamp is to be employed should be each adapted in form and construction to the other parts. In setting forth this invention, therefore7 a complete description will be given of the process of forining and manufacturing all these several parts of the lamp, together with the description of the formation of the globe and process of exhausting and closing the same.

The globe is constructed of a single piece of glass, which is preferably blown into a mold,

whereby all the lamps are rendered uniform the air after the conductors have been secured in place. This is rendered unnecessary for the reason that by this invention the globe is exhausted and closed at the end at or near which the conductors enter. The neck of the globe is afterward narrowed or diminished in size, and it is cut or broken off by a suitable tool near the bulb or globe. The conductingfilament,which will be hereinafter described, is then inserted within the globe, and the conducting-wires leading to the saine are suspended across the edge of the neck of the globe. B means of a blowpipe the glass is then heated 4about the conducting-Wires, which are preferably of platinum. The wires, by reason of their own weight, sink into the glass as it becomes softened, and the glass closes above them. If, however, this action should not take place quick ly enough, a little particle ofglass is fused upon the exposed platinum wire restingon the globe for the purpose ofholding the conductors and the filament firmly during the subsequent manipulations. The portion of the neck which was at rst cut off is then placed against the neck from which it was removed, and the two are welded together by means of a blow-pipe, the two parts occupying thesame relative positions as those they originally held. A platinum or other suitable metallic stopper is then inserted Within the neck formed of the two sections which have been thus welded together into a Whole tube, and the tube is then preferably drawn to a diameter that will prevent the stopper from falling out, or it may be curved to an angle for the same purpose. The air is then exhausted from the globe and the glass is softened around the stopper at the lowest possible temperature and caused to be compressed against the same. rounding atmosphere is compressing the softened glass around the pin or stopper the glass neck is elongated to still further insure the close tting of the pin to the neck of the tube Which'joins the lamp to the air-pump. In the vsides of the neck there are preferably formed. slight depressions,which afford points for the While the sur- IOO holder to grasp the lainp and retain it in its proper position. The neck of the globe or chamber is, however, preferably otherwise straight.

rlhe form of carbon which it is preferable to employ in this globe consists of a carbonized filament formed in the shape of two incomplete circles having preferably slightly different diameters and united with each other by a curved continuation of the filament. The circles of different diameters serve a special purpose in preventing a continued movement of the filament, when the lamp is jarred, by breaking up the vibrations into ones of smaller amplitude. The form of the filament is also of especial advantage for producing and radiating as equal an amount of light as possible from a given length of conductor,and that, too, within as small an area of containing-globe as possible. It has heretofore been proposed to bend a filament upon itself at a sharp angle and to separate the sides or hold them apart by a block or wedge of insulating material. rllhe bent or angled portion is turned or curved forward so that the sides form parallel curves. A filament so shaped, however, is very liable to break at the sharp angle through which the two sides unite with each other, and it is at the same time difficult to construct. By curving the portion uniting the two sides a much stronger and more desirable form is secured. Again, the sides of the loops being parallel with each other and of the same curvature, the light from the inner surface of the one is more or less cut off by the other side of the filament. By having the curves of different radii a broader unobst ructed area or radiating-surface is presented.

lhe supporting conducting-wires for the filament are united thereto by means of a peculiar form of clamp, which is formed at the end of each wire. This clamp is made by forming an enlargement at one end and then causing the enlargement to be flattened into a disk. The disks are doubled, preferably, in the axis of the wire, so that two lips are formed, which are intended to receive the filament between them. The lips are then together bent out laterally, so that they project from `the Ywire at right angles. vOne ofA these conducting-wires is applied to cach extremity of the filament, and they are preferably so ai'- ranged that the lips of the clamps are turned in toward eachother, so as to make use of the resilience ot' the carbon loopl in case of a defective clamping.

Y For the purpose of handling the delicate filaments with facility in introducing the ends into the clamps and for rendering the connection between the ends of' the filament and supporting-conductors as perfect as possible, the ends of' the filament are preferably coated with metal by electrolysis before they are applied to the clamps. The metallic coatings may then be forcibly brought into intimate contact with the clamps by crushing the ends of the filament contained therein. They may afterward be soldered to the clamps, if it is desired.

A suitable bridge-piece of glasspreferably unites the supporting-conductors with each other, for the purpose of stiffening the same and preventing the filament from being displaced.

The operation of coating the ends of the filament with copper or other metal, as well as the details of the construction of the lamp and holder, will be described in connection with the accompanying drawings, in whichd Figure 1 illustrates a complete lamp, together with its holder. Fig. 2 is a side view of the incandescing filament. Figs. 3, 4, and 5 illustrate the mold employed for carbonizing the filament and the method of removing the filaments therefrom. Figs. 6 and 7 illustrate the apparatus employed for coating the ends of the filament. Figs. 8, 9, 10, and 1l illustrate the construction of and the method of manufacturing the supporting-conductors. Fig. 12 illustratesthe form of the globe before the filament has been inserted; and Fig. 13 illustrates the method of inserting the conducting-wires after the section ofthe neck of the globe has been removed. Figs. 14 and 15 illustrate the process of closing the globe. Figs. 16 and 17 illustrate certain detailsin the form and construction of the holder.

Referring to Figs. 1, 2, 3, and 4, a description will first be given of the incandescing filament and the process of forming and manufacturing the saine.

rllhe filament H is constructed from a single piece of cane, bamboo, parchmentized paper, thread, woody ber, or other suitable carbonaceous material, by being subjectedV in a suitable mold to a very high temperature. The form of the filament which is preferred may be described as a loop bent upon itself so as to form two incomplete circles, the one of wliich,h,is preferably of greater diameter than the other,h2. The curved end, 71,3, of the loop unites the two incomplete circles with each other and is at rightangles to them. It may here be observed that an especial advantage is derived from having the two circles of' the loopof different diameters-namely, that is, neither circle intercepts the path of the other when the lamp is viewed from one side,

vbutthe light emitted from each circle is radiated independently of the other. Such a filament is preferably formed by means of a mold of the character illustrated in Figs. 3 and 4. rlhis inold,which is preferably formed of nickel or some form of iron, steel, or carbon, or hydrocarbon,consists of an outer case,H,and an` inner section, H2. The case H has a central bore, li*,of greater diameter at one eXtremityJL, than at the otlieigh. Vithin the bore h4 it is designed that the section H2,constituting a stopper or a plug, shall be inserted. The section H2 of themold tapers at the same angle as the bore l1.4 of the portion H. The two conical contactsurfaces of the sections H. and H2 are ground smooth for the purpose of making ICO IIO

the joint as perfect as possible. surface of the ,section H spiral grooves, k and k2, joined at their inner ends, as shown at k3, by a curved continuation of the grooves. The portion k3 of the mold is preferably cut under slightly for the purpose of preventing the filament from slipping out of lthe groove. The spiral grooves, starting from the portion k3, pass outward toward the respective ends of the section H2 of the molds. It is not essential, however, that the grooves should in all instances be spiral, Vas they may be made parallel. It is designed that the lilament to be carbonized shall be laid in this groove, being wound about the plug H2. The plug or section H2 is then inserted within the section H and driven tightlyinto place. .The mold is then placed in asuitable kiln,with the smaller. endof the tapered lbore downward, and while in the kiln it is subjected to a sufiicient heat to et't'ect the carbonization ot' the iilament.

It is essential that the mold should be perfectly tight during the process of carbonization, and this is one of the objects of tapering the bore h4. lt is evident that during the process of heating the mold the outer section H will expand, causing the diameter of the bore to increase. The section H2, however, may thereupon drop farther into the section H and continue to keep thejoint between the two tight. The section H2 afterward,as it becomes thoroughly heated, expands still more and binds tightly against the inner surface of the bore. The plug H2 is made hollow,so that the heat of the kiln may enter the same and more quickly penetrate the filament which is being carbonized.

The filament, after it has vbeen placed in the groove of the mold, may with advantage be covered and held in position by means of a thread wound about the same and covering it more or less. Such a thread not only serves to hold the lament in position, but also serves Upon the to prevent the filament from being converted4 into carbonio oxide or carboniclacid gas in the event that any oxygen should be present. In Fig. 5 there is'illustrated a mold especially adapted to permit such a thread to be lapplied. In this mold grooves are made for two n'laments, and instead of being spiral in form they are made in the form of complete circles, the grooves la* and k being, respectively, intended to receive the two limbs of the iila ment, while the .portion k serves yto connect thesame. Atpointskland kslightdepressions are made for the purpose of permitting the thread to pass across the filament.

It is well known that during the process of carbonizing the filaments shrink a considerable portion of their length. It is desirable that they should be maintained under tension throughout their lengths during the time such shrinkage takes place. The pressure of the lament against the sides of thel groove in which it is placed secures precisely this result, andan even tension is placed upon the same there are cut two.

throughout its length', although a similar re` sult could be obtained by fastening the end or ends ot' the filament before and during carbonization.

It may be found desirable in some instances to cover the filament after it has been placed in the mold with carbonaceous material for the purpose of more thoroughlyl protecting it from any oxygen which may gain access thereto. This may be accomplished by covering the filament, as already stated," with a thread wrapped about in the groove or coating it with some substance easily applied and melted or distilledaway, like waxor parafine. 'Y

ln practice it is found that when the molds are of iron more or less of the carbon of the iilament will enter into the iron,forming steel throughout the immediate `surfaces of the grooves. For thepurpose of avoidingsuch destruction of the laments, the moldsmay be made of carbon or of some other metal than iron or nickel; but it is preferred to make them of iron and to electroplate thesurfaces of the grooves with nickel. This may be readily accomplished by any of the well-known methods of electroplating. i i

It is necessary to provide some means for removing the filament from the mold after-it has been completely carbonized without do ing injury to it. .When it is desired to remove the filament after carbonizing, the moldV is dropped over a rod, m, (showninFig. 4,) which is approximately the size of the` interior bore ofthe plug H. The rod is cool, and has, therefore, the effect of cooling the interior of the mold more rapidly than the exterior, and thus to produce a consequent contraction of the interior section H2. The rod m extends from a base, m', and is constructed with a screw-thread, m2, upon Vthe rod, designed to receive a suitable nut, m3. This nut is employed to press against a anged washer, m4, which is placedupon the rod after the mold has been placed in position. The flange m5 of the washer rests against the upper end of the mold-section H. By turning the nut m3 downward the washer presses the outer section, H', of the mold downward, causing IOO IKO

it to slip 'by the section H2, the lower end ot' I which is engaged' by an annular shoulder, m, formed at the base of the rod m. A slight movement of the outer section, H', at once separates the two sections of the mold, and the section H2, containing the carbonized filament, may then be readily removed from the outersection without bringing the lament into contact therewith, being guided by the rod m. The filament is then removed from the mold, it being suihoiently exibleto allow of its being bent or sprung outward.

It is desirable that the` filament should be subjected to as high a temperature as possible before it is finally placed in the lamp, for the higher the temperature to which it is exposed the more hard, tough, and iirm will it become. The temperature to which the lamenis may be exposed in the molds is limited to the capacity of the molds to resist the heat and not themselves become melted. When, therefore, the filaments are removed from the molds, it is preferable to pack them in loose carbon powder, and while thus packed they may be subjected to as high temperatures as may be desired. rlhe carbon powder may for convenience be contained in boxes or crucibles made of carbon, clay, or other refractory material, and'a large number may be treated in the same bath. rlhey will be found to retain their shapes during this treatment, and when removed from the carbon powder will be found to be exceedingly hard and tough. The surrounding carbon powder prevents also the access of air to the iilaments both during the process of heating and during the time the filaments are being cooled.

The next step in the process of manufacture is that of electroplating the ends of the lament. The metal which it is usually preferable to employ for this purpose is copper,but other metals may be employed. For this purn pose an apparatus of the character illustrated in Figs. 6 and 7 is employed. This apparatus consists of a clamp, N, having its ends split or cut apart, as shown at n and a2, and provided with set-screws n3 n3. The ends of the iilament are respectively placed in the ends a and n2 of the clamp, and securely held in position by means of the clamping or set screws n3. The entire clamp is thus suspended in any suitable manner with the ends in an electroplating bath, as shown at O, the curved or bent portion of the filament 'extending outside of the bath, as shown in the drawings. Any suitable process of electroplating may then be employed. In the drawings I have shown a battery having one pole connected with the clamp N by a wire or supporting-rod and the other with a copper electrode, 0. tact which exists between the metallic suspending-clamp N and theends of the ilament only a short time is required to completely coat the ends of the filament with copper. After this is accomplished the lament may be removed from the bath, and may be very conveniently handled by taking hold of the copper-plated ends. The ends will bear avery considerablepressure whenthus coated, whereas they are very easily fractured when not so coated. The portions of the filament which were held by the clamps may, if it is so desired, be cut orf, the filament having in the rst place been made of such length as to allow of such portions being removed. By so cutting off the ends of the filament the extremities are left bare-that is to say, not covered by the metal'. This is of especial advantage, because during the process of curing the lilament the fluids contained therein tend to be driven and to collect at the cooler portionsthat is to say, near the ends which are in contact with the support. Now, if the ends were completely covered, the iiuids would be con- Owing to the form ofthe conlined in the carbon surrounded by the metal, but the extremities being open they readily escape therethrough.

The next step in the process of manufacturing the lamp consists in clamping the ends of the electrodes into the supportingcondnctors for the same. Each of these conductors is made in a manner which will be described in connection with Figs. 8, 9, 10, and 1l. At the end of a piece of platinum wire, F, there is fused a globule or ball, f. This ball is either hammered or compressed into a flat disk. The two halves of the disk are bent toward each other, in the manner shown in Fig. 10, along the line of the wire F, and they are then bent` over, as shown in Fig. ll. The two semicircular sections or lips are then clasped upon the metal-coated end of the filament to which it is applied, and, if it is so desired, they may be soldered thereto in any convenient manner.

The two conducting-wires are secured to each other by means of a bridge, f2, of glass. This bridge consists merely of a small section of glass tube having the conducting-wires inserted through it and let into its respective sides by softening the glass or by molding the glass about the wires. The bridge-piece may be applied either before or after the lament has been clamped to the wires.

The filament and the conducti1ig-wires having been prepared in this manner, they are placed within the globe. The diameter, however, of the curve of the filament is preferably made somewhat greater than the diameter of the opening into the globe. for the purpose of giving to the lamp a capacity for giving light as great as possible and for rendering the size of the globe as small as possible relatively to the length of the filament. It is therefore necessary to first insert the loop h3 of the filament into the globe and to spring the entire lament in by slightly bending the double loop during the process. When, however, the loop is once within the globe, it resumes its normal shape and form.

Referring. now to the form and method of constructing the vacuum-chamber and of closing the same, A represents a cylindrical glass tube, at the end of which is a bulb, B, which is preferably formed by blowing into a suitable mold. The bulb B is made of the size which it is desired that the lamp shall have. Instead of blowing'it in a mold, however, it may be blown directly on thepunty from the metal in the glass-makers Crucible, or from a tube of any diameter. The globe, it will be particularly noticed, is thus formed without any projection at the side opposite the tube A, but with an entirely smooth surface. The tube or neck is then narrowed toward the contraction,where it is to be finally closed. The globe is placed in a lathe, and a portion of the neck or tube A is cut off at a point on the curved part which is of less diameter than the neck, as indicated, along the line x x in Fig. 12, leaving a short neck, about one-half IOO l sitions which the two pieces of an inch in' length. Before the section of the neck is cut off, however, a mark is preferably put upon the same to indicate the pooriginally occupied, so that the portion a of the neck or tube can be reapplied to the portion a after the filament and conductors have been inserted in the globe B. The carbon filament, the form and manufacture of which has already been described, is then inserted within the bulb or globe B, the portion h3 being first inserted through the neck a, and the filament being then bent in such a manner as to allow its entire length to be pushed forwardV into the interior of the globe. The flexibility of the filament will permit this to be accomplished, although it would not be possible to bend the two sides of the curved filament toward each other sufficiently to permit the filament to be inserted in a iiattened form. This method of insertion is also applicable to other forms of filaments. After the lament is within the globe it will immediately resume its previous form. After the filament H is placed within the globe the conducting-wires F F, which sustain the-same, are caused to rest across the edge b of the neck a of the globe B in the manner indicated in Fig. 9, and the latter is, by means of a blow-pipe or in any other suitable manner, heated sufficiently to soften the glass around the conducting-wires and to allow themto sink by their own weight into the edge' of the neck, forming slight depressions. The glass,however, will close over the conductors, thus completely embedding them in the neck of the globe and securing a tight joint, or a small piece of glass may be added to each conductor for that purpose, if necessary.

The next step in the process consists in replacing the section a of the tube A upon the neck a of the globe. The marks which were applied before the section was eut off or removed serve to guide the workman in replacing the latter in the precise position which it at first occupied. By means of a blow-pipe or in any other suitable manner the two portions of the glass are then welded together along the line x1 x', as shown in Fig. 10, and the lamp resumes its former shape, the filament H and the conductors F having been inserted. It will be understood, moreover, that the two portions vof the globe are entirely homogeneous and that the disadvantage of having glass of different thicknesses or different qualities in the lamp is entirely avoided. A platinum stopper, d, having at one end a loop or head, e, is then insertedwithin the narrowed opening of the globe or neck, and the tube is narrowed sufflciently to prevent this stopper from falling out. IThe lamp is then applied to an airpump, by means of which the air is exhausted from the chamber. When the vacuum has been formed in the chamber B, the neck of the globe is closed about the platinum stopper d, thus forming a tight joint. It is not found y below the point necessary in so closing the globe to form a temporary sealing at some distance below the point where the globe is permanently closed, as is usually customary inA other forms' of lamp, but the lamp may be closed once for all while still upon the air-pump; and it may be further observed that since the point of closing is at the end of the globe which enters the holder it may be made at such a distance from the globe as may be desired, whereas, in a lamp which is sealed at the other extremity of the globe, it is necessary to form the final"\..`

ing to be done at the glass-blowers table`instead of on the been closed the pump. After the lamp Vhas neck formed or extending of closure may be readily broken off or removed. The unnecessary portion of the platinum stopper may, H by means of any suitable tools, and ground down even with the glass tube, or the neck may be drawn downto a break, and then only the stopper is required to be cut off. p

Itiswell known that platinum when cooled sends out gases which are occluded in the 'metal while it is heated, and for the purpose of preventing such gases from escaping from the stopper into the glass or the tubeit is advisable to conduct the process of closing the glass around the stopper at as low a temperature as possible, or it may sometimes be preferred to coat the latter 'with a thin lm of glass preparatory to inserting it within the globe. By reason of this film of glass gases would not be given off which were occluded before the closing of the globe. The glass, as it is closed about the stopper, enters the pores at the surface of the platinum stopper and forms atghtjoint without forming anychemical union therewith. Such a iilm of glass is preferably applied by first inserting the platinum wire into a tightly-fitting glass tube, then placing the same in a suitable chamber and exhausting the air therefrom. Vhile thus in a vacuum the platinum wire is heated to iucandescence. The gases are thus driven then be cut of IOO IIO

out from the platinum, and the glass then enters the pores of the platinum by reason of the capillary attraction, and in this manner a very close mechanical contact is formed between the two materials. The vacuumchamber may, if it is so desired, be allowed to suddenly fill with air while the platinum is still heated, and the glass will then be brought under a pressure which insures that it will penetrate the pores of i the platinum. Not only may the platinum stopper be thus treated, but the conductors leading to the filament may also be treated in the same manner.V

The platinum-stopper may, instead of being cut off at the end of the beak, be allowed to protrude, and then it may be bent into a loop, as shown in Fig. 10, for the purpose of affording a convenient means of hanging the lamp.

It is desired also to call attention to the fact that the stopper may be placed at the end of the lamp opposite the neck, the usual projection being formed at that end for the purpose.

It remains now to describe the holder which it is preferable to employ for sustaining the lamp in position. Such holder is illustrated in Figs. 1l and l2. Referring to these igures, It represents a suitable calyx of the proper size for receiving the neck B of the lamp.. In this calyx the neck is designed to fit and to be held securely by means of suitable lugs, r', which are Ydesigned to enter depressions r2 formed in the sides of the neck of the lamp. These depressions are formed While the shank about the lamp is still softened by heat.

Soldered to the ends of the supporting couductors F are suitable conductin g-wi res, s and s2, which extend to the lower end of the supporting-calyx It, and through these condul tors it is designed that the connections of the lamp shall be completed. For this purpose a plug or nut, S', is inserted at the lower extremity of the ealyx R, and either screwed into the same Yor tightly fastened in any suitable manner. In the lower ends of the nut or plug there is set a ring, t, of conducting material, surrounding a disk, t2, of like material. The disk and ring are insulated from each other, the nut itself being of insulating material. The conductor s is soldered to the ring t', while the conductor s2 is united with the disk t2. The ring and the disk both preferably project a slight distance beyond the face of the nut.

Asecond'nut, S', is designedto be applied to the extremity of the calyx R, and this nut is providedwith a ring, t3, and disk t, similar to the parts t and The second nut, S2, by being screwed into the case or calyx R, brings the two rings against each other, and likewise the two disks, thus making two perfect electrical connections The ring t3 and the disk t are respectively provided with conductors s3 and s4, which are connected with the connectingwires of the system in which the lamp is to be employed, so that either by screwing the calyx upon the neck or the latter into the calyx thelamp will be placed in circuit.

Ylt is understood that suitable circuit-interrupting devices may be applied to the supporting-calyx, as desired. Instead of two of the depressions and lugs formed in the neck of the lamp for securing the calyx, any number may be employed, and they may be extended throughout the length of the neck, if so desired, for the purpose of preventing the lamp from being turned when in position; or the side of the neck may be flattened, if it is found desirable.

I claim as my inventionl. A filament for incandescent electriclamps, formed in the shape of two incomplete circles united with each other by a curved continuation, substantially as described.

2. A filament forincandescent electriclamps, formed in the shape of two incomplete circles having different radii and united with each other by a curved continuation, substantially as described.

3. A filament for incandescent electric lights, consisting of a conductor formed in an arched loop the sides of which are united by a curved continuation, are approximately parallel, and are bent to form curves, the free ends of which loop are supported, substantially as described.

4. Aiilament for incandescent electriclamps, consisting of a loop of incandescent material, the sides of which are bent so as to form two incomplete circles, and are united with each other by a curved continuation, substantially as described.

5f A carbon lament for incandescent electric lamps, having its respective extremities electroplated with metal before being attached to the conductors, and having its ends bare, substantially as described, in combination with supporting-conductors, to which it is secured by mechanical compression.

6. A carboniilament for incandescent electrie lamps, having its outer extremities covered with a metal which has been applied by electro-deposition, and its ends bare, substantiully as described.

7. A carbon filament for incandescent lamps, having its extremities first coated with a metal by electro deposition, in combination with supporting-conductors, to which it is united by mechanical compression and with which it is afterward soldered, substantially as de scribed.

8. A carbon lament for incandescent electric lamps, having its ends first coated by electro-deposition, in combination with metallic supporting-conductors,to which the respective ends so coated are secured by mechanical compression, substantially as described.

9. An incandescent electric lamp having a carbon lament formed in a curve of greater diameter than the diameter of the opening through. which it was inserted. 10. In combination with the inclosingcham ber of an incandescent electric light, a carbonized filament formed intoaloop havinga curved bight,which loop is constructed in a curve the radius of which is greater than that of the opening through which it isninserted into the chamber.

In testimony whereof I have hereunto subscribed my name this 26th day of July, A. D. 1884:.

OTTO A. MOSES.

W'itnesses:

CARRIE E. DAvIDsoN, GHARLRs A. TERRY.

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