Jasper Republican, Volume 2, Number 8, Rensselaer, Jasper County, 5 November 1875 — Constant Electric Lamp. [ARTICLE]

Constant Electric Lamp.

It is well known that, under the influence of a strong electric current, a body which is a good conductor, when connecting the two poles of the current, may be ■ heated to such a point as to become luminous. This phenomenon la turned to account by Mr. Lodygin, of St. Petersburg, for obtaining a constant light, which is both reasonable in cost and also capable of being used under all circumstances. Instead of producing the electric light by means ofthe wearing away of the electrodes, as has hitherto been the practice, that is to say, by the ignition of the particles of charcoal which are transported from one pole to the other in a body of air heated to a high degree between the electrodes, Mr. Lodygin employs a short stick of charcoal, in a single piece, and reduces the area of its section between the two electrodes in such a manner that it offers considerable resistance to the current; so that the portion between the two poles, being heated to a high degree, becomes luminotis, jußt as a metallic Wire would do. The lamp consists of a cylindrical o glass vessel, closed with metal covers'so as to be air-tight both at top and bottom. Occupying the center of this cylinder is the stick of charcoal held in its place by two pieces of metal communicating, through the covers, with the two electrodes of the battery. In order to render the light more intense several sticks of charcoal may be placed in the same lampThe conducting wire which leads the electricity from tiie battery communicates with an insulated rod connected with the cover and in contact with the first piece of charcoal; the electric current then pasdes into the second piece of charcoal through the lower cover, and from thence to the next lamp or to the battery. On account of the heating of that part of the charcoal which is reduced in thickness the surface rapidly becomes oxidized when in contact with the oxygen of the air, and the charcoal is consequently worn away, a circumstance which would tend to considerably limit the duration of the lamp. To avoid this drawback, however, the lamp is filled with nitrogen, which is prevented from escaping by the two air-tight covers; in this manner oxidation cannot take place, and the pieces of charcoal preserve their original dimensions. The experiments have given such good results that the inventor has been awarded the Loraonossov prize by the St. Petersburg Ac*4e©y of Science.—if. T Qrafhii.