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Patents: 218 of 530	UNITED STATES PATENT OFFICE FRANK MOORE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO GEORGE WESTINGHOUSE, JR., OF SAME PLACE. INCANDESCENT ELECTRIC LAMP.
SPECIFICATION forming part of Letters Patent No. 389,526, dated September 11, 1888. Application filed March 21, 1887. Serial No. 231,696. (No model.)

To all whom it may concern:     Be it known that I, FRANK MOORE, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered a certain new and useful Improvement in Incandescent Electric Lamps, of which improvement the following is a specification.     The object of my invention is to provide an incandescent electric lamp in the illuminating action of which the rays of light evolved from its incandescing carbon shall be thoroughly and effectively moderated and diffused; to which end my improvement consists in an incandescent electric lamp having a facing of fragments of transparent or translucent material secured by soluble glass to its bulb.     The improvement claimed is hereinafter set forth.     In the manufacture of incandescent electric lamps as heretofore practiced it has been sometimes proposed to reduce and diffuse to some degree the light evolved from the incandescing carbon by rendering the bulb of the lamp partially opaque by grinding or corresponding abrasion by a sand blast or by covering the bulb by a separate inclosing-casing, the surface of which is formed of a series of light-diffusing faces or projections.     My improvement is designed to attain the same result in a more thorough and economical manner, and presents the further advantage of enabling the bulbs to serve as shades in addition to their ordinary function of envelopes for the incandescing carbon filaments, thereby diffusing the light and increasing its useful effect, while moderating its intensity and dazzling action.     In the accompanying drawings, Figure 1 is a view in elevation of an incandescent electric lamp in which my invention is applied; and Fig. 2, a partial section, on an enlarged scale, through the same.     In the practice of my invention the carbon filament 2 is inserted in the bulb 1, which is exhausted and sealed in the ordinary manner. The outer surface of the bulb is then coated with a wash or film of solution of silicate of soda or soluble glass, forming a transparent and adhesive base for the connection of the light-diffusing medium. A facing, 3,

composed of small angular fragments of transparent or translucent material-- as crushed glass, porcelain, or the like-- is then applied to and spread over the coating of soluble glass while the same is yet liquid, and upon the setting or hardening of the coating will be securely fixed thereby to the bulb 1. The facing 3 completely surrounds the incandescing carbon 2 and acts as a series of facets or prisms to refract and diffuse the rays of light evolved therefrom, as indicated in the enlarged section, Fig. 2.     The salient feature of my invention consists in the employment of a base or attaching medium for the light-diffusing material which shall not only possess the qualities of transparency and adhesiveness when first applied, but shall also he infusible under any degree of heat to which an incandescent electric lamp is subjected in normal service and insoluble in water, so as to he unaffected by the contact thereof or by atmospheric moisture. I attain by the adoption of soluble glass, which satisfactorily complies with the requirements above stated, a result which would be wholly impracticable with the use of varnish, gum, or other analogous adhesive substances, which have been heretofore proposed as cements in decorating the rear or inner surfaces of articles of glass by attaching thereto a hacking of fragmentary mineral substances.     The manufacture of incandescent electric lamps under my invention involves only an inconsiderable increase of cost over that of lamps of the ordinary construction, and the character of the operation is such that no risk of injury or breakage of the bulbs is sustained. It affords, in addition to its action in moderating and diffusing the light, a novel and tasteful ornamentation for the bulb, and will be found particularly advantageous by reason of the fact that the comparatively intense light of the carbons renders a shade of some description materially desirable, while the short life of the bulb does not justify any substantial expense in that regard.     I am aware that it has heretofore been proposed to ornament glass shades, globes, &c., in the process of manufacturing the same by attaching particles of broken glass thereto by fusion, then crackling the glass by immersion