US877408A - Manufacture of electric incandescent lamps. - Google Patents

Description

PATENTED JANr2 1, 1908 F. M. PB GAZIN. MANUFACTURE OF ELECTRIC INUANDESOENT LAMPS.

APPLICATION FILED MAR.17. 1904.

WIT/1158858.- H441 7 65% ATTOHNEVJ following is a specification No. 786,727-March 3,

UNITED STATES FRANCIS Mi F. CAZIN, OF

HoBoKEN, NEW JERSEY.

MANUFACTURE OF ELECTRIC INGANDESGENT LAMPS.

To all whom it may concern:

Be it known that I, FRANCIS M. F. CAZIN, a citizen of the United States,residing'at 1108 Bloomfield street, in the city of Hoboken, Hudson county, State of' New Jersey, have invented new and useful Improvements in the Manufacture of Electric Incandescent Lamps, Method and Product, of which the The invention relates to the class of electric incandescent lamps disclosed in my prior applications, to wit: December 7, 1892:

er. No. 454,412: Patent No. 523,460July 24, 1893:Ser. No. 481,332: Patent No. 523,461July 24,1893: Ser. No. 481,321: Patent No. 566,285-September 11, 1895: Ser. ,No. 562,189: Patent No. 620,640- October 29, 1895: Ser. No. 567,332: Patent No. 021,291-OQtober 15', 1897: Ser. No. 655,312: Patent No. 621,292-February 2, 1899: Ser.No. 704,218: March 21, 1899: Ser;

No. 709,902: Patent No.-640,366July 27,

1899: Ser. No. 725,288: October 31, 1899: Ser. No. 735,439: January 27, 1900: Ser. No. 3,061: January 7, 1903: Ser. No. 138,084: February 2, 1903: Ser. No. 141,501: Patent 1903: Ser. No. 145,871: August 27, 1903: Ser. No. 170,940: September 1, 1903: Ser. No. 171,515: Patent No. 760,849-November 30, 1903: Ser. No. 183,270.

The invention has, the same as those disclosed in the above-cited applications, the object, to providelor an improved lamp of the designated kind and of a simple, eflicient and efi'ective construction, which will readily serve its intended purpose,and the aforesaid applications are referred to for the purpose of avoiding a repetition of the qualifications of arts and a specification of their functional requirements, so far as not now newly disclosed. 2

The invention which I desire to secure patent for by this present ap )lication, is in further development of detail s in the lightproducing part, viz., in the illuminant of the electric incandescent lamps described by me in my previous applications for patents on such improved'lamps, on which so far seven patents have been issued to me, and I refer to the contents of the records in these said cases, and to the said patents, for all informationthat ma be required for rendering illllls present app 'cation more intelligent-and c ear.- I I In special do I desire to protect this inven- Bpecifiea-tion of Letters Patent.

Application filed March 17 1 Patented Jan. 21, 1908.

1904. Serial 110.198.56 4.

tion in its broader character as an integral luminant structure of a metallic conductive element and a body of rare metal oxids.

My present improvement has mainly the object of substituting in electric incandescent lamps, in place of the present illuminants,

improved light producing parts, such as herebelow disclosed, the general purpose of the improvement herein disclosed being preoisely the same as that of my preceding applications, and especially as that of my prior application No. 735,439, namely the production, at a stated electric current expenditure, of a comparatively and proportionately greater amount of light as against-the lamps of resent trade, and of such light in color anr power as is best adapted to common use, and in lamps lit for being operated for -a longer life time, and to efi'ect such production mainly by the utilization of new materials and hereinafter described in the luminant part or structure of myimproved lamps,

which materials were not before so utilized in the art of electric light making. And as materials utilized by 1118 to the said ell'ect, I mention a certain class of rare metal oxids and a certain class of metals of the osmiumruthenium Find, or class.

Such improvements, relating mainly to the luminantpart or parts or structure of the lamps, I intend as well for electric lamps with one or more protecting glass bulbs, as for such without such protection, as well as for such with such glass bulbs that are filled with air, gas or vapor, as for such that have one or more bulbs aire ;hausted, or have some so filled and another or others exhausted. (Compare my Patents No. 566,258 and No. 621,292).

The improvement or ImprovementsRvhich I desire to obtain patent for by this applica tion were alluded to by me in my applications No. 555,312, of Oct. 15th, 1897, and No. 735,439,011 Oct. 31st, 1899.

I desire it to 'be understood that I do not select carbon or any other material as the material exc'lusively to be used in the electrically heated part of my lamp, but on the contrary I propose to use any one single or mixed or compound material for such partas will adapt itself to the functional performance required in an electric incandescent lamp, such as I. have specified and described heretofore, as aforesaid, and as- I shall describe and specify hercbelow.

The selection of material will in each connatcd by any of the known processes of such ehmmation, for instance, running out by crate case be the'result of the requirements of such case. For instance, whenever I desire to eliminate core or fillet from the luminant or heated part, be it before or be it during the eration of the lamp, then and in that case select a material which can he elimimelting (tin, zinc, bees-wax,) or by the solu tion or wet-extraction process, (metals, etc., easily forming soluble salts with diluted 1 acid).

, When on the other hand I do not desire to eliminate the core or any other structural part of the heated part in my lamp, but do on the contrary desire to reserve the core or other part of such heated part of my lamp, as the means for sup orting the luminant part or structure, in tiat case I'preferably select and use material which, almost to the exclusion of all others for them ain functional performances of conducting and producing gm, I have been using in the heated part or parts or structure of m y lamps, namely, metals and metaloxids, and of the latters preferably certain one or more specified oxids of rare .metals. (Compare my Patents N 0. 621,291, page 1, 88th line, and No.;620,640, page 2, lines 70, etc., and other parts of these patents.)

In the specification to my Patent No. 621,291, issued on my application of October 895, the following definition of these .rild l s given on page 3, lines 95, etc.,

nafi'iely: In using the designation rare metal oxids I intend to designate all those earths or oxids which combine with a high point of fusion, the peculiar qualities of more readily becoming incandescent or'luminous under the influenceof heat than other matter, and without confining myself to the use of single earths or of definite mixtures thereof. Since then the fact has been experimentally established that lime, magnesia and zirconia, though fusing at high'temperature only, do not possess the peculiar qualities which would placethem 1n the class of rare metal oxids, a fact which, though ignored at an earlier period, is at present accepted and corroborated by'all competent experimenters in regard thereto. This has resulted in the acceptance of a class-distinction between earthy oxids, (such as lime, alumina, magnesia and zirconia), and rare metal oxids, (such as the oxygen-compounds in the solid state of beryllium, caesium, cerium, chromium, didymium, erbium, er manium, gallium, indium, iridium, lant anum, lithium, molybdenum, niobium, palladium, rhodium,-ruthenium, rubidium, selenium, scandium, /samarium, tantalum, thalium, telluriurn,-tl1orium, titanium, tungsten,- uranium, vanadium, Wolfram, .and. ytterbium, and others of same functional qualiing a heated art of the conductive element of the lamp y the function of conducting and of resisting to electric current, to the effect of producing heat primarily and not by 'an specifically preferred or selected material,

do use in or for such-part-any material functionally fit, singly or in conjunction with other material to be used in or for such part, be the material carbon or metal or metal oxid, or any mixture thereof, as lon as they or their mixture perform the stated unction, and in regard-to using any class of metal in conjunction with rare metal oxids I refer to my application of Feb. 2,1899, patented on November 13, 1906 to which s ccific reference is hereby made, and whic 'is made a part hereof.

Whenever an attempt was made of utilizing a body of earthy oxids in the luminant of an electric lamp, neither .an increased light efliciency nor a prolongation of life was the effect of such utilization on the lamp, but when I, as disclosed in my application of October 29, .1895, utilized erbia and I 1ndicated,among others, in my amendment of February 10th, 1896, to my application of--October 29, 1895, namely of cylinders or tubes, and, jointlytherewith, of either an electrolytic deposit or of a pseudo fiber or fabric. (Compare my Patent No. 621,291, page 96, etc., and other previous disclosures.) And I may use or not use admixtures with the oxids such as fluor spar, (compare my application No. 704,218yand preceding 'ones,) and may mix in solution or suspension, (compare my Patent No. 621,291, page 1, lines 89 and 90,) the'metallic oxids and their salts. And I do not-exclude from the said oxids even those of the metals; such as herein further specified and-preferably intended for the main conductive element in the form of an electrolytic deposit, which metals, when resent in their metallic form within the body of oxids, assume in part-or in an accessory manner, or even mainly, a

conductive function in connection with such oxid-body or core, as hereinb'elow further ex lained.

nstead of coverin the core, fillet or fila. ment with an oxidfI noW propose to cover the same by someof the metals which will, .nder the mfiuence of the electric current,

the ruthenium osmium class, because their temperature of fusion is so high, that at incandescing white heat they do not melt,

as for instance latinum does, and of other metals I do on y use those which Will not melt at the temperature of white incandeseence, but I may use any other metal or alloyof approximately as high a temperature of fusion,whenever I can, as in the case often alluded to, of iron and carbon, in-

crease their practical infusibility by impregnating them, or mixing with them carbon or some other material, that will have that effect; But even though .and in case I-do .eover, as often described and as hereabove mentioned again, the core, fillet filament or materially heated part of the conductive element, primarily though not ultimatelyconsisting of carbon, with oxid'of any one or of several of the rare metals, as s )ecified -in the 11th paragraph of this speci ication, then the re-action occurs such as by; me

described in myjlatent No. 620,640, on page 2, in lines 99 to 112, as follows:

' \Nhenthe carbon filament is coated very thinly with oxids of'the stated nature and is subjected in vacuo to an electric current, a

- very slight re-action takes place, the simultaneous-result of which is the formation of carbon .oxid and'the deposition on the fila- -o eration is continued until the metallic s '11 is, minutely thin as it may be, homogeneous, the re-action will cease.

And in so far as most of these rare metals also partake in the characteristics of high temperature of fusion and great allinity to oxyen, by which they class physically and chemreally with those of the ruthenium osmium class, they are also subject to the hereabove specified entering into a compound or into a mutual impregnation with the material of the core, or a remainder thereof, forming a compound or mutual impregnation, analogcus to steel, with the metal reduced as aforesaid from its 'oxids as present originally, to

its metallic form as hcrcabove also specified, be it in part or entirely. ()n account'of the metals of the ruthenium osmium class singly being non-ductile and on account of an electrolytic deposit of any single such metal being crystalline, while my invention also contern plates the use of such singlemetal, though it be brittle and not preferable for the stated purpose, I prefer to mix more than one 'of these metals in solution in the electrolyte, by doing which I produce electrolytically an amorphous, tenacious, ductile coating, referably mixing osmiate of potash and c orid of iridium.

As indicated I preferably employelectrolytic deposition of such metals as I intend to ap ly to a prime Y core. I

from all that W ich in the preceding paragraph has been stated in the qualification of the metals, entering into the by me invented alloy-filament, which as disclosed in my application No. 725,283-of July 27, 1899 it is evident beyond a possible doubt, that'thev metal platinum does not thereto belong,'su ch having been long known to the art as absolutelyunfit for the function as filament in any incandescent lamp, an unfitness which it im parts in a more or less high degree to all of its alloys, even with the by me selected metals of the ruthenium osmium class, to

which platinum does not belong,- althou h chemically it ranges in their proximity. ts physical qualities, which alone determine its fitness or unfitn'ess, are much Inferior to those of the metals of the ruthenium osmium' class, when the requirements in a filament are considered. As well and generally known, platinum melts before it is made to fully inincandesee under electric current. On the other hand itsaflinity to oxygen is much less ,active. or practically inactive, while in its pure state it is highly ductile and not brittle, or powderable, as the metals of the ruthenium osmium class in their native state c'x-.

elusively are. (Compare my Patent No. 523,400, page 3, line 121..) Notwithstanding these good qualities, the fact that it melts before attaining the temperature of white ineaiuleseemze, renders platinum, as stated, unfit for the function assigned to the coatings or cores in the. luminant, as herein disclosed by this applicant. v

Before immersing the filament-core in the electrolyte l may prepare its surface for the deposit of osmium-iridium, etc, by a primary deposit. of zinc and by bringing the zinccovcr into contact with mercury, respcctively amalgainate the same, or I may primarily clectrolytically deposit any other metal, and i may amalgamate such other metal such as copper, or I may expose. it directly to further electrolytic deposition.

It is by this process of intermediate coating that I succeed in producing a uniform cover of osmium-iridium, or of other metals of the same or equivalent class.

It goes without saying that zinc, mercury or any other metal, in tern'iediately used, disment into an exhausted bulb, or'into a functional equivalent thereof, and have the current turned on, at the proper moment, even while completing the exhaustion, or when avirtual vacuum has been effected, and when there is' carbon present, aside from eventual evaporation of such-carbon, a carburiz ion of metal'takes lace, and it depends o the proportionate t ickness of metal and of caron, Whether the carburization takes in the entire carbon part, or all of the metal-cover, or leaves some carbon, orsome metal, yet intact, In both cases I have product-e afilament for electric vacuum lamps of highly im roved character, as hereabovc specified. ncrease of tensionin the current to a certain voltage destroys the purely carbon filament. The same tension produces in the metal (osmium-iridium,- etc.,) covered filamerit eventual c'arburization only, the filament continuing under all normal tension to maintain its shapeand to emanate light.-

But even the thus "obtained and improved filament 'is by mefurther improved in the method already disclosed as heretofore stated in' my application No. 655,312.

If I desire to so further improve the filament in my lam 1 cause a further electrolytic deposit on t e osmium-iridium cover, and for such deposit I select a metal or metals of the rare-metal class. the oxids of .which have hereabove been mainly cited, and mixtures of these oxids; and as heretofore stated in I my application No. 655,312, I enter the com pound filament, as described, into the artially 'air-exhaustedbulb, or its equiva ent, such as the bell jar of an air exhausting a paratus. Unless the filament was previous y oxidized on its surface, l'then and there subject the same to electric current and ermit artial or entire oxidation of the-meta coat, liefore, in case a bulb has been used, sealing the same. a

The electrolytic deposition of rare metals, such as specified, is conditioned on the absen cc of water in the electrolyte because with water present some of the stated rare metals, in the nascent state oxidize in decomposing water, 1 therefore in the first instance may select a primary deposition in a nonaqueous electrolyte and subsequent addition of water thereto. instead of oxidizing in air or oxygen a primary metal-deposit. By such oxidation the surface of the filament, then covered with adhesiv'e rare-metal oxid, possesses the quality of reducing the da1'k-heat-raysin I proportion to increasing the emanated light,

the entire filament performing the functions of conducting the current and of producing heatand light.

When producing: by my new process the stated metaland oxid-lihnnent, such as described hereabove in particular, I. found that I obtained a filament of less brittleness, of

greater co-hesiveness and of increased torsional strength, because, 1st. I avoid using the metals in either gaseous or molten form. 2nd. I prepared an electrolyte in liquid form at normal templrature. 3d. I introduced and used more tnan one of these metals in the liquid electrotype. 4th, I so adapted to' the purpose the mixture of solutions and the dimensions of the electric current applied to the electrolytic action, and the direction of current, that a metal deposit was formed, containing more than one of the stated metals and each in proper proportion.

It is absolutely immaterial, as far as the solution is concerned, whether the deposit be used later as conductor at normal tempera ture or at suitably increased temperature, and whether incandescence be the direct consequence of heat, or whether heat roduce intermediately conductivity and t en incandescence, the observable and useful eflect being entirely and absolutely the same, whichever the scientific explanation be,

" given for the phenomenon of incandescence produced in normally non-conductive matter under current. But a plicant states, that he; in harmony with al scientifieauthorities on such matter, rejects the explanation, that oxids, when they have been made to incandesce under electric current,assume the function, such as in science is understood to be that of an electrolyte, and that the oxide then constitute: a solid electrolyte, or an electrolytic conductor, though in absolute absence of electrodes.

By all scientific and technical terminology,

lege,and to attribute that,whieh is known j to be, and by all scientists of repute accepted to be: chemical reaction under electric current and by the heat thereby set free,

a (a reaction, which is successfully prevented under these conditions by chemical insulation)to an electrolytic wandering of material ions,'an efl'ect never proven'or corroborated by'any scientist, except the pseudoscientist, who originated-the false teaching. (Compare in The XX th Century Electric Light, pages 4.5, 46 and 56 and applicants Patent 620,640.) I

It is equally immateriah whether the electrode used in the deposition ,of metal receive the deposit on its faces exclusively or in its pores also.

I consider the product obtained- (preferably carbureted osmium with'a minoradmixture ol iridiuml as analogous to steel when compared with iron, where a'yery small presence of carbon changes the physical qualities of the iron, or as analogous to the various rare-metaL-oxids, where the presence of one such-as ceria, as a small fraction of the Whole, such as thor ia .'changes entirely the light-producing quality of the whole, the effect not being dependent on the presence of carbon. Morever I am fully aware of the general faculty, as stated, of carbon, of increasing the resistance to fusion of the so carbureted metals, such as the cited steel and carbureted osmium-iridium,

and therefore I include these carbon-metalcompounds as the material used in building up singly or in combination with other ma terial the luminant of my improved electric incandescent lamps.

The electrical current-expenditure in the lamp with the newly discovered improved filament, is reduced to. 1:5 to 2 Watts p candle ower, the former being the main result, w en such a filament is further embedded in a thin coat of rare metal oxid,

and the current applied may be of higher tension, than applicable with an exclusively carbonor exclusively metal-filament. And I found thefunctional qualities of a filament having a surface of metal of the ruthenium osmium class,materiall'yenhanced by coating the same with another metal of less affinity to oxygen but of a similar resistanceto fusion and evaporation, while in the metallic state, it becoming possible by such coating to use the coated nlament either in an airfilled bulb or housing or even under free access of the atmosphere.

The by me improved electrolytic process of manufacturing the luminant in my improved lamps, such as preferably applied by me, is

in its general character the same, as indicated by the adjoined drawing (Fig. 1) which originally formed part of my a plication No. 655312, but was withdrawn therefrom previous to issue of patent No. 621292. It shows that the twoends of the filament-core,

as-one electrode, are attached to the same pole. The other electrode may be dispensed with in its complicated form, as long as this second pole is immersed into the electrolyte. I preferably prepare the liquid electro yte by dissolving osmiate of potash mainly with a small admixture of chlorid of iridium. And I assume that the deposition of the two metals is brought about in a secondary reaction, hydrogen being set free and reabsorbedin a double reaction. not only but the product also thereof may be further described as follows In the first instance, I do not necessarily use the core in the electrolyte in its final form (horse shoe or other) but my product being ductile, I have the facility for bending the filament as by me produced, when it is set up on the glass-base.

In the second instance, when using a metallic core, I do not select platinum as such but I do select a metal as core which (such as tin or zinc) I can and do discard by melting or by evaporation or solution, leaving the two or more composite metals of the This process ruthenium osmium class in tubular form mainly, thereby imparting to the filament made thereof a greater tensile strength. 31*

In the third instance, I. do not use any of the stated class of metals in molten or vapor form, but do use them exclusively in liquid solution thereby avoiding the poisonous effect of these metals in such form, and from such solution I preferably deposit, not one metal at a time, but I deposit more than one of these metals simultaneously.

In the fourth instance, I preferably coat the fi ament made of these stated metals with a coat-of fine metal viz. metal, which, when heated in air, will not oxidize and which protects them against ox genation and other deterioration, such a fine metal being selected in i'iorsi i'eration also of its temperature of fusion and evaporation.

In the fifth instance, when one metal exclusively is deposited it a pears in crystalline structure of very small extremely brittle and non-ductile, and 'without the homogeneity, which is absolutelyindispensable for the performance of its intended function, while on the other hand the two metals deposited in mixture or as alloy b the electrolytic process now by me discloset have an amorphous. homogeneous inner structi'ire of great cohesiveness which befits them forthe intended'function as a stable protection and sup ort of a conductive fillet or nsa stable com uctive element in themselves In the sixth instance, whenever the fillet or core is of carbon, then a reaction takes place as already stated hcreabove, which in order to produce a practicable filament, must both be known a nd be met in the making of a filament. Un specially rovidcd for or met by the pro er remedy, t is reaction leaves no luminant, such consisting of carbon and a stated metal, but it leaves a lumiuant of one sole material only, namely, of a carbon compmmd of the stated metal.

cohesiveness and And the dual nature or material in the prod not can be preserved only, by proportioning the carbon and metal to the effect of such reaction leaving unabsorbed a remainder of either or of both, because they are protected mutually by the intermediate compound of both resulting from the reaction. Then the luminant becomes a three-part luminant, consisting of a conductive core, of a chemical insulation thereof and of a metallic alloy, which may serve as such as a luminant or may further be iin roved by a cover of raremetal-oxids. In t e latter case the carboncompound and the metal jointly constitute the chemical insulation between carbon and ox'ids.

The cause, wh at no time the one-metal carbon filament ias made its appearance in trade, must be found in the nature of the described, which renders the luminant thus made essentially non-feasible, non-usable or filed Wltltlll original'application No. 655,--

unfit for its purpose; on account mainly of brittleness and excessive conductivity. On the other hand the by me disclosed rocess produces a practicable and improve luminant, fit for its intended function and in fact a new and improved luminant of superior -:fitness and light-elfect, and according to the highest authorities the discovery of analloy,

which, as a substitute for a singlemetalf.

.1 possesses greaterfitness for a technical purpose and produces an improved result and product, constitutes an invention. In describing'the apparatus, represented in Fig. 1, which Fig. 1 is a copy of a figure 3,

312- on Octo er 1 5, 1897,I repeat verbally my statement, as containedon the last page of said application, preceding the formulated claims, of which 11 and 1.2 read as follows: 11. An electrolytic apparatus, in which the carbon-filament of anincandescent lamp is attached with its two ends to the negative pole and is surr'o'u'nded in the bath by a metal-anode the form of which is adapted to the loop-form of the filament. 12. The

method of electrolytically precipitating a solid coat on a carbon filament, by attachingboth ends of the filament to the negative pole of the electrolytic apparatus, immersi the.

filament-loop into theelectrolyte name y;

I'consider as my invention t e arrangement of a-carbon filament to form the negative pole in an electrolytic bath in a loopshape, similar to the sha e, in which it is to be used in the lam wit out direct connection with the positive pole, "such as used in the common flashing process. I attach importance to the form of the metal, used as the positive pole in the bath, by which form the carbon-loop B is in close opposition or proximity and at mainly uniformdistance to and from the plate of metal g, that acts as the positive electrode or anode, and which plate 9 is continuous in itself and to the positive ole And e marks the connecting wires lietwcen the negative pole N and the carboncore B, B. while B marks the part of the electrolytic deposit, which faces the plate B directly, the extreme )arts of lighter deosits not beinglmarkeil specially, but being limited only by the line of immersion e".. C isthe connecting lug and P is the metallic receiver for the wires e and the plu C It is obvious, that the entire process oes' not depend on the precise form of the positive pole as-indicated, and that any other form or shape of the positive electrode, as a whole or spread or divided into branches may be used for obtaining essentially the. same effect, it being evidently and obviously sufficient that the ositive pole or electrode be submerged as the negative electrode is, as shown in Fig. 1, the negative-one to the full extent and including the terminals, that it is intended to plate the conductive element or filament,-an d that the positive electrode have on or in or about it a sufficient uantity of the material to be taken up by t e electrolyte and to be deposited on the negative electrode. And in Whichever cup or vessel or trough, dish or indenture the positive electrode ends, I fill it with the osmiate of potash. and chlorid of iridium, or withsuch other compounds as will contain two or. more metals of the stated class, which I desire to' simultaneously deposit on the filament, be it carbon or metal. And with the required modifications I make use of the same arrangement that it was originally intended for, namely for a deposition of a metal of the rare metal class, intended thereafter to be oxidized in part or entirely, etc.

The exact proportion of the different metals to be deposited jointly and in the same 'eleetroly tic manipulation is a matterof adaptation to such requirements or to.func.

tional conditions. Moreover it should be understood, that my fundamental idea of utilizing dark heat-rays for the increase of light, and producing the necessity of pres;

serving as much heat as practicable in the lamp, and carried out by the introduction of an extra bulb, with or'without provision for differential cooling of the inner bulb for purposes-clearly set-forth in my patent No. 621292, is also applicable to the luminant part of the specific constitut-ion, as herein set forth. And I should further say as to the form of such illuminant part, though such form in its main total will preferably be cylindrical, and concentrical I may make use of bends and windings of the entire luminant part, and I may make use of bends and windings of a core part within a coating part, for the purpose of regulating their pro-- portionate conductivitywhile theirrelations as core and cover be maintained. Such variations of form are incidental only, and

a mere matter of proper adaptation to required functions.

Speaking generally it is immaterial what proportions of osmium and iridium be used, as the beneficial results of their combination are obtained when the two metals are used in widely different ratios, and therefore-for the purpose of economy and conven'ience, and in order to avoid the necessity of the isolation of those metals, which is expensive, I may use a olution obtained by dissolving the'nuggets known to metallur- (Comgists as iridosmine or -osmirid. pare bulletin of U. S. Geological Survey, No. 193)..

Having thus ilu-Qbl'lbfid my invention what I claimand desire to secure by Letters'Pat-' cut, is:-

1. A luminant for electric incandescent.

lamps, consisting of. a carbon filet, asurrounding layer of a mixture of carbon and metals, and a layer of the ruthenium-smium metals surrounding the same.

' 2. A filament or luminant for electric incandescent lamps, composed primarily of a core carbon, surrounded by an electrolytic coating of metal, the several materials of which the filament is composed, being so proportioned, that after the filament has been subjected to heat it will consist partly of carbon partly of the product of the reaction between carbon and metal and partly of metal.

3. A filament or luininant for electric incand escent lamps, composed primarily of a :carbon core, a thereon electrolytically plated coat ofmetals, of which the surface concentrical layer is oxidized on its surface-- ically a carbon-fillet-electrode, including its terminals or joints to the current-leading wires, with metal.

5. The method of manufacturing luminants or filaments for electric incandescent lamps, Which consists in electrolytically plating a carbon-fillet-elcctrode, including its terminals or joints to the current-leading, Wires, with metal of the ruthenium-osmium group of metals and oxidizing the same on their exposed surface.

' 6. The method of manufacturing lurninants or filaments for electric incandescent lamps, which consists in electrolytically plating a carbon-fillet-electrode with metal of the ruthenium osmium group of metals, and by subjecting such plated luminant to a slowly increasing electric current, whereby I is produced such moderate reaction between carbon and metal, as will not disintegrate the luininant but will prevent subsequent further reaction between component materials.

7. The method of manufacturing filaments for electricincandescent lamps,which method consists" in electrolytically plating a carbon-filament in its intended final bending and servin as anode, with sundry metals and in finishing ofi" such filament by subjecting the same-to an electric current of slowly increasing tension.

FRANCIS M. r.- CAZIN VVitnessesi I R. B, IIOOVER, C. F. HEssER.

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